START WORK FORM (CERN)
CURRENT MEASURES TAKEN
NO PROVISION AGAINST ACTS OF GOD (OR FUTURE GOD-PARTICLES)
Baguette Dropped By Bird Shuts Down The Large Hadron Collider (Really)
BY Stuart Fox / 11.05.2009
The Large Hadron Collider, the world’s most powerful particle accelerator, just cannot catch a break. First, a coolant leak destroyed some of the magnets that guide the energy beam. Then LHC officials postponed the restart of the machine to add additional safety features. Now, a bird dropping a piece of bread on a section of the accelerator has, according to the Register, shut down the whole operation. The bird dropped some bread on a section of outdoor machinery, eventually leading to significant over heating in parts of the accelerator. The LHC was not operational at the time of the incident, but the spike produced so much heat that had the beam been on, automatic failsafes would have shut down the machine. This incident won’t delay the reactivation of the facility later this month, but exposes yet another vulnerability of the what might be the most complex machine ever built. With freak accident after freak accident piling up over at CERN, the idea of time traveling particles returning from the future to prevent their own discovery is beginning to seem less and less far fetched.
EMERGENCY DUMP CORE
BY Lewis Page / 5th November 2009
A bird dropping a piece of bread onto outdoor machinery has been blamed for a technical fault at the Large Hadron Collider (LHC) this week which saw significant overheating in sections of the mighty particle-punisher’s subterranean 27-km supercooled magnetic doughnut. According to scientists at the project, had the LHC been operational – it is scheduled to recommence beaming later this month – the snag would have caused it to fail safe and shut down automatically. This would put the mighty machine out of action for a few days while it was restarted, but there would be no repeat of the catastrophic damage suffered last September. On that occasion, an electrical connection in the circuit itself failed violently, causing a massive liquid-helium leak and knock-on damage along hundreds of metres of magnets. Reg readers alerted us yesterday to the temperature rises in the LHC’s Sector 81, which began in the early hours of Tuesday morning: most of the collider’s operational data can be viewed on the web for all to see. Initial enquiries to CERN press staff led to assurances that the rises were the result of routine tests. However Dr Mike Lamont, who works at the CERN control centre and describes himself as “LHC Machine Coordinator and General Dogsbody” later confirmed that there had indeed been a problem. Lamont, briefing reporters at the control room yesterday, told the Reg that machinery on the surface – the LHC accelerator circuit itself is buried deep beneath the Franco-Swiss border outside Geneva – had suffered a fault caused by “a bit of baguette on the busbars”, thought perhaps to have been dropped by a bird. As a result, temperatures in part of the LHC’s circuit climbed to almost 8 Kelvin – significantly higher than the normal operating temperature of 1.9, and close to the temperature at which the LHC’s niobium-titanium magnets are likely to “quench”, or cease superconducting and become ordinary “warm” magnets – by no means up to the task imposed on them. Dr Tadeusz Kurtyka, a CERN engineer, told the Reg that this can happen unpredictably at temperatures above 9.6 K. An uncontrolled quench would be bad news with the LHC in operation, possibly leading to serious damage of the sort which crippled the machine last September. At the moment there are no beams of hadrons barrelling around the huge magnetic doughnut at close to light speed, but when there are, each of the two beams has as much energy in it as an aircraft carrier underway. If the LHC suddenly lost its ability to keep the beam circling around its vacuum pipe, all that energy would have to go somewhere – with results on the same scale as being rammed by an aircraft carrier.
But there’s no cause for concern, according to Lamont. The LHC’s monitoring and safety systems have always been capable of coping with an incident of this sort, and have been hugely upgraded since last September. Had this week’s feathered baguette-packing saboteur struck in coming months, with a brace of beams roaring round the LHC’s magnetic motorway, the climbing temperatures would have been noted and the beams diverted – rather in the fashion that a runaway truck or train can be – into “dump caverns” lying a little off the main track of the LHC. In these large artificial caves, each beam would power into a “dump core”, a massive 7m-long graphite block encased in steel, water cooled and then further wrapped in 750 tonnes of concrete and iron shielding. The dump core would become extremely hot and quite radioactive, but it has massive shielding and scores of metres of solid granite lie between the cavern and the surface. Nobody up top, except the control room staff, would even notice. This whole process would be over in a trice, well before the birdy bread-bomber’s shenanigans could warm the main track up to anywhere near quench temperature. Should the magnets then quench, no carrier-wreck catastrophe would result. According to Lamont, provided the underlying fault didn’t take too long to rectify, the LHC could be up and beaming again “within, say, three days” following such an incident. We asked if more such incidents would occur, once the Collider is up and running for real from later this month. “It’s inevitable,” the particle-wrangling doc told the Reg. “This thing is so complicated and so big, it’s bound to have problems sometimes.” Meanwhile, it would seem that this particular snag has been solved, as the Sector 81 temperatures are now headed back down to their proper 1.9 K.
SAFETY POLICY AGAINST BACKWARD CAUSATION?
The Collider, the Particle and a Theory About Fate
BY Dennis Overbye / October 12, 2009
More than a year after an explosion of sparks, soot and frigid helium shut it down, the world’s biggest and most expensive physics experiment, known as the Large Hadron Collider, is poised to start up again. In December, if all goes well, protons will start smashing together in an underground racetrack outside Geneva in a search for forces and particles that reigned during the first trillionth of a second of the Big Bang. Then it will be time to test one of the most bizarre and revolutionary theories in science. I’m not talking about extra dimensions of space-time, dark matter or even black holes that eat the Earth. No, I’m talking about the notion that the troubled collider is being sabotaged by its own future. A pair of otherwise distinguished physicists have suggested that the hypothesized Higgs boson, which physicists hope to produce with the collider, might be so abhorrent to nature that its creation would ripple backward through time and stop the collider before it could make one, like a time traveler who goes back in time to kill his grandfather.
Holger Bech Nielsen, of the Niels Bohr Institute in Copenhagen, and Masao Ninomiya of the Yukawa Institute for Theoretical Physics in Kyoto, Japan, put this idea forward in a series of papers with titles like “Test of Effect From Future in Large Hadron Collider: a Proposal” and “Search for Future Influence From LHC,” posted on the physics Web site arXiv.org in the last year and a half. According to the so-called Standard Model that rules almost all physics, the Higgs is responsible for imbuing other elementary particles with mass. “It must be our prediction that all Higgs producing machines shall have bad luck,” Dr. Nielsen said in an e-mail message. In an unpublished essay, Dr. Nielson said of the theory, “Well, one could even almost say that we have a model for God.” It is their guess, he went on, “that He rather hates Higgs particles, and attempts to avoid them.” This malign influence from the future, they argue, could explain why the United States Superconducting Supercollider, also designed to find the Higgs, was canceled in 1993 after billions of dollars had already been spent, an event so unlikely that Dr. Nielsen calls it an “anti-miracle.”
You might think that the appearance of this theory is further proof that people have had ample time — perhaps too much time — to think about what will come out of the collider, which has been 15 years and $9 billion in the making. The collider was built by CERN, the European Organization for Nuclear Research, to accelerate protons to energies of seven trillion electron volts around an 18-mile underground racetrack and then crash them together into primordial fireballs. For the record, as of the middle of September, CERN engineers hope to begin to collide protons at the so-called injection energy of 450 billion electron volts in December and then ramp up the energy until the protons have 3.5 trillion electron volts of energy apiece and then, after a short Christmas break, real physics can begin.
Maybe. Dr. Nielsen and Dr. Ninomiya started laying out their case for doom in the spring of 2008. It was later that fall, of course, after the CERN collider was turned on, that a connection between two magnets vaporized, shutting down the collider for more than a year. Dr. Nielsen called that “a funny thing that could make us to believe in the theory of ours.” He agreed that skepticism would be in order. After all, most big science projects, including the Hubble Space Telescope, have gone through a period of seeming jinxed. At CERN, the beat goes on: Last weekend the French police arrested a particle physicist who works on one of the collider experiments, on suspicion of conspiracy with a North African wing of Al Qaeda.
Dr. Nielsen and Dr. Ninomiya have proposed a kind of test: that CERN engage in a game of chance, a “card-drawing” exercise using perhaps a random-number generator, in order to discern bad luck from the future. If the outcome was sufficiently unlikely, say drawing the one spade in a deck with 100 million hearts, the machine would either not run at all, or only at low energies unlikely to find the Higgs. Sure, it’s crazy, and CERN should not and is not about to mortgage its investment to a coin toss. The theory was greeted on some blogs with comparisons to Harry Potter. But craziness has a fine history in a physics that talks routinely about cats being dead and alive at the same time and about anti-gravity puffing out the universe. As Niels Bohr, Dr. Nielsen’s late countryman and one of the founders of quantum theory, once told a colleague: “We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct.”
Dr. Nielsen is well-qualified in this tradition. He is known in physics as one of the founders of string theory and a deep and original thinker, “one of those extremely smart people that is willing to chase crazy ideas pretty far,” in the words of Sean Carroll, a Caltech physicist and author of a coming book about time, “From Eternity to Here.” Another of Dr. Nielsen’s projects is an effort to show how the universe as we know it, with all its apparent regularity, could arise from pure randomness, a subject he calls “random dynamics.” Dr. Nielsen admits that he and Dr. Ninomiya’s new theory smacks of time travel, a longtime interest, which has become a respectable research subject in recent years. While it is a paradox to go back in time and kill your grandfather, physicists agree there is no paradox if you go back in time and save him from being hit by a bus. In the case of the Higgs and the collider, it is as if something is going back in time to keep the universe from being hit by a bus. Although just why the Higgs would be a catastrophe is not clear. If we knew, presumably, we wouldn’t be trying to make one.
We always assume that the past influences the future. But that is not necessarily true in the physics of Newton or Einstein. According to physicists, all you really need to know, mathematically, to describe what happens to an apple or the 100 billion galaxies of the universe over all time are the laws that describe how things change and a statement of where things start. The latter are the so-called boundary conditions — the apple five feet over your head, or the Big Bang. The equations work just as well, Dr. Nielsen and others point out, if the boundary conditions specify a condition in the future (the apple on your head) instead of in the past, as long as the fundamental laws of physics are reversible, which most physicists believe they are. “For those of us who believe in physics,” Einstein once wrote to a friend, “this separation between past, present and future is only an illusion.” In Kurt Vonnegut’s novel “Sirens of Titan,” all of human history turns out to be reduced to delivering a piece of metal roughly the size and shape of a beer-can opener to an alien marooned on Saturn’s moon so he can repair his spaceship and go home. Whether the collider has such a noble or humble fate — or any fate at all — remains to be seen. As a Red Sox fan my entire adult life, I feel I know something about jinxes.
Search for Effect of Influence from Future in Large Hadron Collider
BY Holger B. Nielsen, Masao Ninomiya (Submitted on 13 Jul 2007 (v1), last revised 4 Nov 2009 (v4)
“We propose an experiment which consists of drawing a card and using it to decide restrictions on the running of Large Hadron Collider (LHC for short) at CERN, such as luminosity, and beam energy. There may potentially occur total shut down. The purpose of such an experiment is to search for influence from the future, that is, backward causation. Since LHC will produce particles of a mathematically new type of fundamental scalars, i.e., the Higgs particles, there is potentially a chance to find unseen effects, such as on influence going from future to past, which we suggest in the present paper.”
Test of Influence from Future in Large Hadron Collider; A Proposal
BY Holger B. Nielsen, Masao Ninomiya
“We have earlier proposed the idea of making card drawing experiment of which outcome potentially decides whether Large Hadron Collider (LHC for short) should be closed or not. The purpose is to test theoretical models which, like e.g. our own model that has an imaginary part of the action with much a similar form to that of the real part. The imaginary part has influence on the initial conditions not only in the past but even from the future. It was speculated that all accelerators producing large amounts of Higgs particles like the Superconducting Super Collider (SSC for short) would call for initial conditions to have been so arranged as to finally not allow these accelerators to come to work. If there were such effects we could perhaps provoke a very clear cut “miracle” by having the effect make the drawn card be the one closing LHC. Here we shall, however, discuss that a total closing is hardly needed and seek to calculate how one could perform checking experiment for the proposed type of influence from future to be made in the statistically least disturbing and least harmful way. We shall also discuss how to extract most information about our effect or model in the unlikely case that a card restricting the running of LHC or the Tevatron would be drawn at all, by estimating say the relative importance of high beam energy or of high luminosity for the purpose of our effect.”
Card game restriction in LHC can only be successful!
BY Holger B. Nielsen, Masao Ninomiya (Submitted on 2 Oct 2009 (v1), last revised 23 Oct 2009 (this version, v3))
“We argue that a restriction determined by a drawn card or quantum random numbers, on the running of LHC (Large Hadron Collider), which was proposed in earlier articles by us, can only result in an, at first, apparent success whatever the outcome. This previous work was concerned with looking for backward causation and/or influence from the future, which, in our previous model, was assumed to have the effect of arranging bad luck for large Higgs producing machines, such as LHC and the never finished SSC (Superconducting Super Collider) stopped by Congress because of such bad luck, so as not to allow them to work.”
An iterated search for influence from the future on the Large Hadron Collider
BY Iain Stewart
“We analyse an iterated version of Nielsen and Ninomiya (N&N)’s proposed card game experiment to search for a specific type of backward causation on the running of the Large Hadron Collider (LHC) at CERN. We distinguish “endogenous” and “exogenous” potential causes of failure of LHC and we discover a curious “cross-talk” between their respective probabilities and occurrence timescales when N&N-style backward causation is in effect. Finally, we note a kind of “statistical cosmic censorship” preventing the influence from the future from showing up in a statistical analysis of the iterated runs.”
Holger Bech Nielsen
email : hbech [at] nbi [dot] dk
email : ninomiya [at] pref.okayama [dot] jp
email : iains [at] mit [dot] edu
Spooky Signals from the Future Telling Us to Cancel the LHC!
BY Sean Carroll / 10.14.2009
A recent essay in the New York Times by Dennis Overbye has managed to attract quite a bit of attention around the internets — most of it not very positive. It concerns a recent paper by Holger Nielsen and Masao Ninomiya (and some earlier work) discussing a seemingly crazy-sounding proposal — that we should randomly choose a card from a million-card deck and, on the basis of which card we get, decide whether to go forward with the Large Hadron Collider. Responses have ranged from eye-rolling and heavy sighs to cries of outrage, clutching at pearls, and grim warnings that the postmodernists have finally infiltrated the scientific/journalistic establishment, this could be the straw that breaks the back of the Enlightenment camel, and worse.
Since I am quoted (in a rather non-committal way) in the essay, it’s my responsibility to dig into the papers and report back. And my message is: relax! Western civilization will survive. The theory is undeniably crazy — but not crackpot, which is a distinction worth drawing. And an occasional fun essay about speculative science in the Times is not going to send us back to the Dark Ages, or even rank among the top ten thousand dangers along those lines. The standard Newtonian way of thinking about the laws of physics is in terms of an initial-value problem. You specify the state of the system (positions and velocities) at one moment, then the laws of physics tell you how it will evolve into the future. But there is a completely equivalent alternative, which casts the laws of physics in terms of an action principle. In this formulation, we assign a number — the action — to every possible history of the system throughout time. (The choice of what action to assign is simply the choice of what laws of physics are operative.) Then the allowed histories, the ones that “obey the laws of physics,” are those for which the action is the smallest. That’s the “principle of least action,” and it’s a standard undergraduate exercise to show that it’s utterly equivalent to the initial-value formulation of dynamics.
In quantum mechanics, as you may have heard, things change a tiny bit. Instead of only allowing histories that minimize the action, quantum mechanics (as reformulated by Feynman) tells us to add up the contributions from every possible history, but give larger weight to those with smaller actions. In effect, we blur out the allowed trajectories around the one with absolutely smallest action. Nielsen and Ninomiya (NN) pull an absolutely speculative idea out of their hats: they ask us to consider what would happen if the action were a complex number, rather than just a real number. Then there would be an imaginary part of the action, in addition to the real part. (This is the square-root-of-minus-one sense of “imaginary,” not the LSD-hallucination sense of “imaginary.”) No real justification — or if there is, it’s sufficiently lost in the mists that I can’t discern it from the recent papers. That’s okay; it’s just the traditional hypothesis-testing that has served science well for a few centuries now. Propose an idea, see where it leads, toss it out if it conflicts with the data, build on it if it seems promising. We don’t know all the laws of physics, so there’s no reason to stand pat.
NN argue that the effect of the imaginary action is to highly suppress the probabilities associated with certain trajectories, even if those trajectories minimize the real action. But it does so in a way that appears nonlocal in spacetime — it’s really the entire trajectory through time that seems to matter, not just what is happening in our local neighborhood. That’s a crucial difference between their version of quantum mechanics and the conventional formulation. But it’s not completely bizarre or unprecedented. Plenty of hints we have about quantum gravity indicate that it really is nonlocal. More prosaically, in everyday statistical mechanics we don’t assign equal weight to every possible trajectory consistent with our current knowledge of the universe; by hypothesis, we only allow those trajectories that have a low entropy in the past. (As readers of this blog should well know by now; and if you don’t, I have a book you should definitely read.)
To make progress with this idea, you have to make a choice for what the imaginary part of the action is supposed to be. Here, in the eyes of this not-quite-expert, NN seem to cheat a little bit. They basically want the imaginary action to look very similar to the real action, but it turns out that this choice is naively ruled out. So they jump through some hoops until they get a more palatable choice of model, with the property that it is basically impotent except where the Higgs boson is concerned. (The Higgs, as a fundamental scalar, interacts differently than other particles, so this isn’t completely ad hoc — just a little bit.) Because they are not actually crackpots, they even admit what they’re doing — in their own words, “Our model with an imaginary part of the action begins with a series of not completely convincing, but still suggestive, assumptions.”
Having invoked the tooth fairy twice — contemplating an imaginary part of the action, then choosing its form so as to only be relevant where the Higgs is concerned — they consider consequences. Remember that the effect of the imaginary action is non-local in time — it depends on what happens throughout the history of the universe, not just here and now. In particular, given their assumptions, it provides a large suppression to any history in which large numbers of Higgs bosons are produced, even if they won’t be produced until some time in the future. So this model makes a strong prediction: we’re not going to be producing any Higgs bosons. Not because the ordinary dynamical equations of physics prevent it (e.g., because the Higgs is just too massive), but because the specific trajectory on which the universe finds itself is one in which no Higgses are made.
That, of course, runs into the problem that we have every intention of making Higgs bosons, for example at the LHC. Aha, say NN, but notice that we haven’t yet! The Superconducting Supercollider, which could have found the Higgs long ago, was canceled by Congress. And in their December 2007 paper — before the LHC tried to turn on — they very explicitly say that a “natural” accident will come along and break the LHC if we try to turn it on. Well, we know how that turned out. But NN have an ingenious suggestion for saving us from future accidents at the LHC — which, as they warn, could endanger lives. They propose a card game with more than a million cards, almost all of which say “go ahead, no problem.” But one card says “don’t turn on the LHC!” In their model, the nonlocal effect of the imaginary part of the action is to ensure that the realized history of the universe is one in which the LHC never turns on; but it doesn’t matter why it doesn’t turn on. If we randomly pick one out of a million cards, and honestly promise to follow through on the instructions on the card we pick, and we happen to pick the card that says not to turn it on, and we therefore don’t — that’s a history of the universe that is completely unsuppressed by their mechanism. And if we choose a card that says “go ahead,” well then their theory is falsified. (Unless we try to go ahead and are continually foiled by a series of unfortunate accidents.) Best of all, playing the card game costs almost nothing. But for it to work, we have to be very sincere that we won’t turn on the LHC if that’s what the card says. It’s only a million-to-one chance, after all.
Note that all of this “nonlocal in time,” “receiving signals sent from the future” stuff is a bit of a red herring, at least at the classical level. We often think that the past is set in stone, while the future is still to be determined. But that’s not how the laws of physics operate. If we knew the precise state of the universe, and the exact laws of physics, the future would be as utterly determined as the present (Laplace’s Demon). We only think otherwise because our knowledge of the present state is highly imperfect, consisting as it does as a few pieces of information about the coarse-grained state. (We don’t know the position and velocity of every particle in the universe, or for that matter in any macroscopic object.) So there’s no need to think of NN’s imaginary action as making reference to what happens in the future — all the necessary data are in the present state. What seems weird to us is that the NN mechanism makes crucial use of detailed, non-macroscopic information about the present state; information to which we don’t have access. (Such as, “does this subset of the universe evolve into the Large Hadron Collider?”) That’s not how the physics we know and love actually works, but the setup doesn’t actually rely on propagation of signals backwards in time.
At the end of the day: this theory is crazy. There’s no real reason to believe in an imaginary component to the action with dramatic apparently-nonlocal effects, and even if there were, the specific choice of action contemplated by NN seems rather contrived. But I’m happy to argue that it’s the good kind of crazy. The authors start with a speculative but well-defined idea, and carry it through to its logical conclusions. That’s what scientists are supposed to do. I think that the Bayesian prior probability on their model being right is less than one in a million, so I’m not going to take its predictions very seriously. But the process by which they work those predictions out has been perfectly scientific.
There is another reasonable question, which is whether an essay (not a news story, note) like this in a major media outlet contributes to the erosion of trust in scientists on the part of the general public. I would love to see actual data one way or the other, which went beyond “remarkably, the view of the common man aligns precisely with the view I myself hold.” My own anecdotal observations are pretty unambiguous — the public loves far-out speculations like this, and happily eats them up. (See previous mocking quote, now applied to myself.) It’s always important to distinguish as clearly as possible between what is crazy-sounding but well-established as true — quantum mechanics, relativity, natural selection — and what is crazy-sounding and speculative, even if it’s respectable speculation — inflation, string theory, exobiology. But if that distinction is made, I’ve always found it pretty paternalistic and condescending to claim that we should shield the public from speculative science until it’s been established one way or the other. The public are grown-ups, and we should assume the best of them rather than the worst. There’s nothing wrong with letting them in on the debates about crazy-sounding ideas that we professional scientists enjoy as our stock in trade.
The disappointing thing about the responses to the article is how non-intellectual they have been. I haven’t heard “the NN argument against contributions to the imaginary action that are homogeneous in field types is specious,” or even “I see no reason whatsoever to contemplate imaginary actions, so I’m going to ignore this” (which would be a perfectly defensible stance). It’s been more like “this is completely counter to my everyday experience, therefore it must be crackpot!” That’s not a very sciencey attitude. It certainly would have been incompatible with all sorts of important breakthroughs in physics through the years. The Nielsen/ Ninomiya scenario isn’t going to be one of those breakthroughs, I feel pretty sure. But it’s sensible enough that it merits disagreement on the basis of rational arguments, not just rolling of eyes.
FEYNMAN’S THEORY OF POSITRONS
R. P. Feynman / Department of Physics, Cornell University / 8 April 1949
“In this solution, the “negative energy states” appear in a form which may be pictured (as by Stückelberg) in space-time as waves traveling away from the external potential backwards in time. Experimentally, such a wave corresponds to a positron approaching the potential and annihilating the electron. A particle moving forward in time (electron) in a potential may be scattered forward in time (ordinary scattering) or backward (pair annihilation). When moving backward (positron) it may be scattered backward in time (positron scattering) or forward (pair production).”
THAT GODDAMN PARTICLE
Search for the God Particle
BY Mohammad Gill / November 29, 2007
“The (Higgs’) boson is so central to the state of physics today, so crucial to our final understanding of the structure of matter, yet so elusive, that I have given it a nickname: the God Particle. Why God Particle? Two reasons. One, the publisher wouldn’t let us call it the Goddamn Particle, though that might be a more appropriate title, given its villainous nature and the expense it is causing. And two, there is a connection, of sorts, to another book, a much older one….” (Leon Lederman with Dick Teresi, The God Particle, pp. 22-23)
The other, much older, book that Lederman has alluded to in the frontispiece is of course the Bible (Genesis 11: 1-9). He has described these verses under a cynical title of “The Tower and the Accelerator.” The tower is the Babel Tower. And then he has parodied these verses under “The Very New Testament, 11: 1″ in which he has written: “And the Lord came down to see the accelerator, which the children of men builded. And the Lord said, Behold the people are unconfounding my confounding. And the Lord sighed and said, Go to, let us go down, and there give them the God Particle so that they may see how beautiful is the universe I have made.”
And the metaphorical name stuck fast like the super-glue. Some scientists including Peter Higgs don’t like this name. According to Ian Sample (The god of small things, Guardian, November 17, 2007), “The name has stuck but makes Higgs wince and raises the hackles of other theorists. ‘I wish he (Lederman) hadn’t done it,’ he says. ‘I have to explain to people it was a joke. I’m an atheist, but I have an uneasy feeling that playing around with names like that could be unnecessarily offensive to people who are religious.’”
What is the God Particle?
According to Peter Rogers, Editor of Physics World, “In 1993 the UK’s science minister at the time, William Waldegrave, asked physicists to explain in simple terms – and on one side of A4 – what the Higgs boson is, and why they wanted to find it. With a bottle of vintage Champagne on offer for the best explanation, physicists rose to the challenge with analogies that ranged from cocktail parties to space having a ‘grain’ like a piece of wood, albeit in an abstract space rather than real space. In the latter example, particles that travel with the grain have no mass, like the photon, while those that travel against the grain have large masses, like the W and Z bosons.”
A similar story of selling the Superconducting Super Collider (SSC) to President Reagan is described by Ian Sample and a different version is described by Lederman in The God Particle. According to Sample, “The man charged with selling the SSC to Reagan was Alvin Trivelpiece, then director of the office of energy research. Tivelpiece, an exceptionally astute physicist, had heard the president’s sight was failing, and prepared his presentation on two large easels, which he dragged into the Oval Office. There, he likened the SSC’s task to using the bullets to find billiard balls hidden in bales of hay. ‘I knew the one thing they would understand was guns,’ Trivelpiece told me.” The project was however cancelled by the Congress in 1993 because it was very expensive to build. Its estimated cost was more than 12 billion dollars.
These brilliant analogies aside, let me explain as follows. In 1964, Peter Higgs formulated a field theory, which now is called Higgs theory, and showed how the particles acquire their mass. Ever since Newton had introduced mass in his work, majority of the scientists took mass as granted – it simply existed and was there. Many others were however puzzled. Higgs theory explained how the elementary particles acquire mass. According to Higgs theory, mass is “produced by a new type of field that clings to particles wherever they are, dragging on them and making them heavy. Some particles find the field more sticky than others. Particles of light (massless photons) are oblivious to it. Others have to wade through it like an elephant in tar. So, in theory, particles can weigh nothing, but as soon as they are in the field, they get heavy,” (Ian Sample). This explanation is so fundamental that the physicists believe Higgs theory is basically correct and the evidence for its correctness should exist. Hence the rationale for finding the Higgs boson.
The messenger particle of this field is called Higgs boson, the god particle. If this particle is found Higgs theory will be vindicated. Ever since this theory was propounded and its initial success demonstrated by Weinberg and Salam who unified the electromagnetic and weak forces using the mechanism Higgs had suggested, the search is on for the god particle. Pursuit of no other scientific theory has been neither so intensely single-minded nor so expensive, even the search for cure for cancer, as the search for Higgs boson. It is so because very much depends on it. The theory provides explanation to dark matter, dark energy and host of other important missing pieces in physics and might further help to unify the fundamental forces of nature which the string theorists and other physicists are trying so very hard to achieve.
Although the god particle is technically called Higgs boson after Peter Higgs, Higgs work was preceded by the work of two others. They are Robert Brout and Francois Englert. They published their independent work a few weeks earlier than Higgs. Somehow Higgs name got stuck as the name of the particle. One of Higgs’ colleagues presented a seminar in Germany and described the particle as Higgs particle. Robert Brout was sitting there in the front row and when the lecturer saw him and realized his mistake, he tried to amend it by saying, “Of course I know this was also discovered by others but I refer to it with the shortest name. ‘My name has five letters too,’ piped Brout,” (Ian Sample).
Accelerators and the Colliders
One can not understand the physics of the past several decades without understanding the nature of the accelerator and its accompanying array of particle detectors, the dominant tools in the field for the past forty years. Soon after 1909-11 when Ernst Rutherford and his students collaborated to conduct the scattering experiment by bombarding a gold leaf with the alpha particles, a new experimental physics, high energy physics, was born ushering the era of the accelerators and colliders. The underlying idea was quite simple (in the hindsight). We can study the intricacies of the structure of an atom if its nucleus is smashed to yield its constituent subatomic particles. In order to do so, we need very high energies to smash the nucleus or other subatomic particles. Effectively, by doing so we are trying to simulate the physical condition that prevailed in the universe instantaneously after the big bang and before the cooling began after sudden inflation. At that time, matter was in the form of atoms and subatomic particles. After the inflation, the universe cooled and the particles coalesced to form huge lumps of mass in the form of the stars and galaxies.
Higgs boson is very unstable and is prone to decay instantaneously. If we want to detect the existence of a Higgs boson, we need first to create it by smashing subatomic particles using the required amount of energy and then detect it instantaneously. Hence the need for the super-energetic colliders and highly sensitive detectors. Many universities and research centers have accelerators of various kinds and various sizes which are appropriate to their educational and research needs and more importantly which they can afford. It is not intended herein to describe all these various accelerators or even enumerate them; only those which are relevant for detecting the Higgs boson will be briefly mentioned.
According to Lederman, “..the Higgs particle with the lowest mass (there may be many) must ‘weigh’ less than 1 TeV, “(The God Particle, p.376). And he also wrote, “There is no accelerator on earth (as of 1993, the date of publication of his book) that has the energy to create a Higgs particle as heavy as 1 TeV. You could however build one,” (p. 376).
The situation has changed since then. By the way, 1 TeV is equal to 10^12 (1 trillion) eV. One eV is the kinetic energy gained by an electron passing through a potential difference of 1 volt. Great hopes of finding Higgs boson are pinned on the Large Hadron Collider (LHC) located at CERN (European Council for Nuclear Research) near Geneva, Switzerland. It is due to be operational by May 2008. “The collider is contained in a tunnel with a circumference of 26.659 kilometer, at a depth ranging from 50 to 175 meters underground,” (Large Hadron Collider, Wikipedia). The tunnel was formerly used to house the LEP (Large Electron Positron) collider. The LEP was one of the largest accelerators ever made which could accelerate the electrons and positrons to a total energy of 45 GeV (billion eV). It was designed to capture the Z boson which has a mass of 91 GeV. The LEP was shut down near the end of 2000 to make room for the LHC. It operated from 1989 to 2000.
While it is almost certain that the LHC will create Higgs boson, if such a particle ever existed, encouraging data is coming out of the Fermilab near Chicago (Batavia). The Tevatron which is located in a 4 mile long circular tunnel is presently the most powerful accelerator in the world with an energy of 2 TeV (LHC will surpass it when it becomes operational next year). It thus is suitable to detect Higgs boson. The SSC was intended to enhance the capability of the Tevatron but was cancelled by the Congress in 1993 as already mentioned above. One of the other reasons (apart from the cost) for its cancellation was speculated to be the end of the cold war and competition with the USSR. The LHC will essentially serve the purpose which was intended of the SSC.
Are We There Yet?
A rumor flying around physics departments these last few weeks claims that physicists working at the Tevatron, an accelerator located outside of Chicago, have found something new. Originally passed by word of mouth and private e-mail, the rumor made it into the blogosphere May 28 (2007), with an anonymous comment on the blog of a particle physicist living in Venice, Italy. Since then, the rumor has spread, (Owen Weatherall, Quantum Scoop, June 4, 2007). The rumor is just a rumor without any reliable confirmation from any trustworthy source. However, it did spread far and wide and generated a lot of excitement among the bloggers. Dennis Overbye, a science reporter for The New York Times, discussed it at length in his article (At Fermilab, the Race is on for the God Particle, July 24, 2007).
There had been rumors in the past also. Previously, a rumor spread that Higgs boson was detected from “a signal obtained at the large electron-positron collider (LEP) in Geneva, Switzerland, which has now been dismantled to make way for the large hadron collider,” (God particle may have been seen, BBC News Online science staff). Nothing came of it.
Earlier this year, a rumor was attributed to John Conway, a physicist belonging to the Collider Detector at Fermilab (CDF), that his “team had found a signal which, in particle physics had a 2-sigma (standard deviation) significance – a 1 in 50 chance of being a random fluctuation. Normally, to merit new particle status a signal must be significant to 5-sigma – where there’s only a 1 in 10 million chance of it being a fluctuation.” So why all this excitement? It was believed that this particle may be one of the five Higgs particles predicted by the super-symmetry theory. But it all fizzled out later.
In December 2006, a claim was made based on the information coming out from the University of Buffalo (UB) that a “cousin of Higgs boson was detected.” It was attributed to Dr. Piyare Jain, UB professor emeritus in the Department of Physics, who claimed that “a particle with no charge, a very low mass and a lifetime much shorter than a nanosecond, known as the axion, has been detected,” (http://www.scienceagogo.com/news/20061106200405data_trunc_sys…). “This particle was in my original paper in 1974,” Jain said.
Nobel prize physicist in the making / June 14, 2008
The visit was kept secret. So when scientists and technicians working in the vast research tunnel buried deep underground in Geneva saw an elderly man with a shock of white hair and large, thick spectacles being led on a guided tour, they thought little of it. Only later, when a rumour began to sweep round the European Organisation for Nuclear Research (Cern) facility did they realise his significance. Peter Higgs, now 79 but still sprightly, is the reason they are working on what is the largest, most expensive physics experiment ever conceived. By the time Higgs reached the canteen during his visit last April, the word was out about his presence. Professors with PhDs and a lifetime’s work in particle physics, hard-bitten laboratory technicians, and fresh-faced recent graduates clamoured round him. Some sought his autograph, others just wanted to meet him, to be in his company. A shy, modest man, he found the attention overwhelming. Not for the first time in his life, he might have reflected on how one idea he had 44 years ago, one moment of grasped insight, has come to define him. He signed his name, he spoke politely and respectfully to individuals and the crowd, and although deeply unassuming, he even agreed to a brief, and small, press conference at the end of his stay. Then he returned to his flat in Edinburgh, the place he has called home since he started working at the city’s university in his thirties, where he strives to keep the fuss around him at arm’s length. He understands, though, that in the next 12 months it will become increasingly difficult to evade the commotion.
In the summer of 1964, Higgs found himself pondering a problem in the field of particle physics that was proving obstinate: while objects, like a brick, say, have mass that comes from the atoms that make it up, the constituents of the atom are weightless. The puzzle of where mass comes from was recognised, but not one of the pressing issues of the day, yet Higgs came up with an elegant theory that filled this gap of knowledge. He proposed that a force field exists that all particles must pass through. Some are slowed down more than others by the field, making them heavier. Expanding this theory, he proposed that a particle exists, which he called a scalar boson, which clings to other particles as they pass through the field, so conveying mass upon them. His theory was radical and it wasn’t until an American physicist, Steven Weinberg, referred to it — and coined the terms Higgs mechanism, Higgs field and Higgs boson in a scientific paper in the early 1970s, that it became widespread. Now, Higgs’s work is considered a fundamental part of the Standard Model, the accepted theory that for more than three decades has been used to describe the interactions between the fundamental particles that make up the universe. The Higgs boson, however, has never been identified, evading all attempts to discover it. At Cern, the hope is that this final breakthrough is about to be made. “I shall open a bottle of something,” Higgs said when asked at the press conference what he would do if the Higgs boson is found. “It will be champagne — whisky takes a little more time to drink.”
The experiment at Cern is vast in scope and ambition. About £3 billion has been spent on the research, based around the Large Hadron Collider (LHC), the largest, most powerful high-energy particle accelerator ever built, and more than 2,000 physicists from almost 36 countries have worked on the project. When the LHC is switched on, which is due to happen next month, two beams of protons, each less than a hair’s breadth in diameter, will hurtle round the 17-mile tunnel, before slamming into each other. The collision is expected to mirror the conditions of the big bang that created the universe, and the belief is that among the scattered debris will be the Higgs boson. Four giant detectors — one, Atlas, is 150ft long and weighs 7,000 tons — will conduct the search. “All this is important because it tells us how the universe works,” explains John Ellis, a physicist at Cern. “People have been trying to figure out how the universe works ever since they noticed that there is a universe out there. Without Peter’s work, we wouldn’t have theories that made any sense. There’s no doubt in my mind that if and when the Higgs boson is discovered, Peter will be on the first plane to Stockholm.”
The reference to the Nobel prize is commonplace. Higgs’s theory has long been accepted, but only when it has been proven can it be recognised for the Nobel prize. He is perhaps only half-joking when he remarks: “I have to ask my GP to keep me alive.” Due to the precise nature of the work of the LHC, it could take up to a year for the results to be verified. In the meantime, Higgs will continue to treasure his quiet life. He does not own a computer, so he does not respond to e-mails. Nor does he answer the telephone unless he knows who is calling. Journalists trying to arrange an interview must send a letter, and even then he will only respond to established science correspondents whom he trusts. The reluctance is partly for his privacy, partly because he became embroiled in a brief spat with Stephen Hawking six years ago, after Hawking bet a colleague £100 that the Higgs boson would never be found (they have since settled their differences). Mostly, though, the reticence is because Higgs is so diffident about his standing. When asked to place him in the pantheon of theorists, Ellis pauses only briefly before saying, “comparisons with Einstein come to mind. It would be a little bit much to say he’s at that level, but he’s certainly at the next level”. Higgs, though, bridles at such effusive praise. A book by the Nobel laureate Leon Lederman was titled The God Particle in reference to the Higgs boson, conferring further significance on Higgs’s theory. Lederman wanted it to be called The Goddamn Particle, but his publishers opted for God instead. “I wish he hadn’t done that,” Higgs later said. “I have to explain to people it was a joke. I’m an atheist, but playing around with names like that could be unnecessarily offensive to people who are religious. I get very uneasy when people try to attach too much importance to me. All I was doing was bringing together things we already knew about the universe.”
Higgs was born in Newcastle in 1929 and because he suffered from asthma, and because his father’s job as a BBC sound engineer involved much travelling round the country, he was home-schooled for a time. After the family moved to Bristol, Higgs attended Cotham Grammar, where he would stand during morning assembly and look at the names of the school’s alumni. The name Paul Dirac was listed more than any other and Higgs became gripped by the work of a man who was the founding father of quantum mechanics. The schoolboy became engrossed in physics and has spoken of the wonder of “understanding the world”. At 17, Higgs went to City of London School to do mathematics, and soon emerged as one of the most gifted students. Yet the path to Oxford and Cambridge seemed to him to be a kind of resignation. “Some of the family attitude to Oxford and Cambridge rubbed off on me,” he later explained. “Those places were all very well for the children of the idle rich, but if you were serious about university, you went somewhere else.” So he opted for King’s College, London, then moved to Edinburgh in his early thirties, even although his lack of practical skills prompted teachers to warn him that he would “never make it as a physicist”. Edinburgh had already enchanted Higgs during childhood hiking trips. A CND activist when he lived in London, it was at a meeting in Edinburgh that he met Jo, an American linguist who became his wife, and it was when the couple’s planned camping weekend in the west Highland’s was washed out by heavy rainfall that he returned to Edinburgh and devised his groundbreaking theory.
Higgs submitted his paper to a journal editor, who was based at Cern, but it was rejected because it was not considered relevant. A dejected Higgs wrote to another student, saying “This summer I have discovered something totally useless”, but he expanded his paper and sent it to an American journal, where it was published. A lecture tour of America followed. Unknown to Higgs and the rest of the physics world, two Belgians, Robert Brout and Francois Englert, had come up with the same theory, at the same time. All three are now credited with coming up with the theory, although it is Higgs whose name became attached to it, and all three are expected to receive the Nobel prize if the Higgs boson is discovered. “I have no resentment with respect to Higgs,” says Brout, 79. “I find it amazing how perfect a gentleman he is. He has been more than fair. That it is called the Higgs mechanism is not due to him. I admire Peter, he wrote a beautiful paper and he’s done very nice independent work. There is no aggravation, I’m very happy to be associated with this work; it is one of the fine things in my life.”
Higgs tries to evade being pigeon-holed and clings to his principles. He left CND when the group began campaigning against nuclear power, and left Greenpeace when the group opposed genetically modified organisms. A Dutch film crew, two years into making a documentary on the search for the Higgs boson, eventually won his agreement to be interviewed, and despite his reluctance they found him to be a warm, funny, engaging individual, but one who has no need for recognition. “He realises that more and more the press are trying to get hold of him, but it’s not the first time in his life that there’s been this excitement,” says Jan van den Berg, the documentary’s director. “In Cern’s previous experiment, there was a moment when they thought they’d found the Higgs Boson. He’s a very modest man, but he knows very well what it’s all about.”
An art lover and keen hillwalker, Higgs keeps in touch with former colleagues at Edinburgh University, where staff at his old department have become pseudo gatekeepers, trying to manage the interest that is building in his life and work. “His work has become such a focal point of the entire worldwide particle physics activities,” says Richard Kenway, a physics professor at Edinburgh University who worked with Higgs. “He hasn’t been allowed to forget the significance of that experimental quest. His view of things is that obviously it’s important that people discover the Higgs boson, but actually that’s more about finishing off a piece of work that we think we understand. The other things that LHC is likely to discover are vastly more exciting for our understanding of the world.” All the fuss is, to Higgs, immaterial. “I’m worried about the next few months that there’s going to be an outbreak of attention,” he said recently. “It’ll be a relief for them to find it. If I’m wrong, I’ll be rather sad.”
COLDEST MAN-MADE PLACE IN KNOWN UNIVERSE
LHC gets colder than deep space
BY Paul Rincon / 16 October 2009
The Large Hadron Collider (LHC) experiment has once again become one of the coldest places in the Universe. All eight sectors of the LHC have now been cooled to their operating temperature of 1.9 kelvin (-271C; -456F) – colder than deep space. The large magnets that bend particle beams around the LHC are kept at this frigid temperature using liquid helium. The magnets are arranged end-to-end in a 27km-long circular tunnel straddling the Franco-Swiss border. The cool-down is an important milestone ahead of the collider’s scheduled re-start in the latter half of November. The LHC has been shut down since 19 September 2008, when a magnet problem called a “quench” caused a tonne of liquid helium to leak into the LHC tunnel. After the accident, the particle accelerator had to be warmed up so that repairs could take place.
The most powerful physics experiment ever built, the Large Hadron Collider will recreate the conditions just after the Big Bang. It is operated by the European Organization for Nuclear Research (Cern), based in Geneva. Two beams of protons will be fired down pipes running through the magnets. These beams will travel in opposite directions around the main “ring” at close to the speed of light. At allotted points around the tunnel, the proton beams cross paths, smashing into one another with cataclysmic energy. Scientists hope to see new particles in the debris of these collisions, revealing fundamental new insights into the nature of the cosmos.
The operating temperature of the LHC is just a shade above “absolute zero” (-273.15C) – the coldest temperature possible. By comparison, the temperature in remote regions of outer space is about 2.7 kelvin (-270C; -454F). The LHC’s magnets are designed to be “superconducting”, which means they channel electric current with zero resistance and very little power loss. But to become superconducting, the magnets must be cooled to very low temperatures.
Large hadron collider at Cern
For this reason, the LHC is innervated by a complex system of cryogenic lines using liquid helium as the refrigerant of choice. No particle physics facility on this scale has ever operated in such frigid conditions. But before a beam can be circulated around the 27km-long LHC ring, engineers will have to thoroughly test the machine’s new quench protection system and continue with magnet powering tests. Particle beams have already been brought “to the door” of the Large Hadron Collider. A low-intensity beam could be injected into the LHC in as little as a week.
Officials now plan to circulate a beam around the LHC in the second half of November. Engineers will then aim to smash low-intensity beams together, giving scientists their first data. The beams’ energy will then be increased so that the first high-energy collisions can take place. These will mark the real beginning of the LHC’s research programme. Collisions at high energy have been scheduled to occur in December, but now look more likely to happen in January, according to Cern’s director of communications James Gillies.
Feeling the squeeze
Dr Gillies said this would involve delicate operation of the accelerator. “Whilst you’re accelerating [the beams], you don’t have to worry too much about how wide the beams are. But when you want to collide them, you want the protons as closely squeezed together as possible. He added: “If you get it wrong you can lose beam particles – so it can take a while to perfect. Then you line up the beams to collide. “In terms of the distances between the last control elements of the LHC and the collision point, it’s a bit like firing knitting needles from across the Atlantic and getting them to collide half way.”
Officials plan a brief hiatus over the Christmas and New Year break, when the lab will have to shut down. Although managers had discussed working through this period, Dr Gillies said this would have been “too logistically complicated”. The main determinant in the decision to close over winter were workers’ contracts, which would have needed to be re-negotiated, he said. An upgraded early warning system, or quench protection system, should prevent incidents of the kind which shut the collider last year, officials say. This has involved installing hundreds of new detectors around the machine. Cern has spent about 40m Swiss Francs (£24m) on repairs following the accident, including upgrades to the quench protection system.
ALWAYS IN THE SHOP
Before scientists can put the Large Hadron Collider back to work this month solving the mysteries of particle physics, the LHC’s engineers face critical repairs to the $5-billion device. First up: Fix the 53 superconducting magnets trashed in September 2008 when a power cable broke, causing the magnets to warm above their –458˚F operating temperature and lose conductivity, or “quench.” Then pipes for helium coolant melted, further damaging the magnets. Here, the other key upgrades and a few of the thousand chores still to go:
1. Drill eight-inch relief valves into half of the 1,232 dipole magnets that steer the proton beam around the track, to allow for a controlled pressure release in case of another leak.
2. Install a new quench-protection system, which is 1,000 times as sensitive as its predecessor and shuts off the accelerator if it detects an abnormal voltage increase—an indicator of a heat spike.
3. Search for and eliminate electrical faults between the magnets—especially where the cables join—which could increase electrical resistance, causing the cables to overheat and melt.
4. Cool the entire 17-mile track back down to –458˚F with liquid helium. (Engineers brought the sections up to room temperature so they could work inside the tunnel.)
5. Ramp up the current in the magnets from a couple hundred amps to 6,000 over a few weeks. During this time, test the quench-protection system by intentionally overheating the magnets.
6. Perform the final machine check, covering some 10,000 items, such as the systems that inject the proton beam into the collider and extract it within 1/5,000 of a second if a magnet fails.
MEANWHILE : REVERSE TIME
If the experiment works, a signal could be received before it’s sent
BY Tom Paulson / November 15, 2006
If his experiment with splitting photons actually works, says University of Washington physicist John Cramer, the next step will be to test for quantum “retrocausality.” That’s science talk for saying he hopes to find evidence of a photon going backward in time. “It doesn’t seem like it should work, but on the other hand, I can’t see what would prevent it from working,” Cramer said. “If it does work, you could receive the signal 50 microseconds before you send it.” Uh, huh … what? Wait a minute. What is that supposed to mean?
Roughly put, Cramer is talking about the subatomic equivalent of arriving at the train station before you’ve left home, of winning the lottery before you’ve bought the ticket, of graduating from high school before you’ve been born — or something like that. “It probably won’t work,” he said again carefully, peering through his large glasses as if to determine his audience’s mental capacity for digesting the information. Cramer, an accomplished experimental physicist who also writes science fiction, knows this sounds more like a made-for-TV script on the Sci Fi Channel than serious scientific research. “But even if it doesn’t work, we should be able to learn something new about quantum mechanics by trying it,” he said. What he and UW colleague Warren Nagourney plan to try soon is an experiment aimed at resolving some niggling contradictions in one of the most fundamental branches of physics known as quantum mechanics, or quantum theory. “To be honest, I only have a faint understanding of what John’s talking about,” Nagourney said, smiling. Though claiming to be “just a technician” on this project, Cramer’s technician partner previously assisted with the research of Hans Dehmelt, the UW scientist who won the 1989 Nobel Prize in physics.
Quantum theory describes the behavior of matter and energy at the atomic and subatomic levels, a level of reality where most of the more familiar Newtonian laws of physics (why planets spin, airplanes fly and baseballs curve) no longer apply. The problem with quantum theory, put simply, is that it’s really weird. Findings at the quantum level don’t fit well with either Newton’s or Einstein’s view of reality at the macro level, and attempts to explain quantum behavior often appear inherently contradictory. “There’s a whole zoo of quantum paradoxes out there,” Cramer said. “That’s part of the reason Einstein hated quantum mechanics.” One of the paradoxes of interest to Cramer is known as “entanglement.” It’s also known as the Einstein-Podolsky-Rosen paradox, named for the three scientists who described its apparent absurdity as an argument against quantum theory.
Basically, the idea is that interacting, or entangled, subatomic particles such as two photons — the fundamental units of light — can affect each other no matter how far apart in time or space. “If you do a measurement on one, it has an immediate effect on the other even if they are separated by light years across the universe,” Cramer said. If one of the entangled photon’s trajectory tilts up, the other one, no matter how distant, will tilt down to compensate. Einstein ridiculed the idea as “spooky action at a distance.” Quantum mechanics must be wrong, the father of relativity contended, because that behavior requires some kind of “signal” passing between the two particles at a speed faster than light. This is where going backward in time comes in. If the entanglement happens (and the experimental evidence, at this point, says it does), Cramer contends it implies retrocausality. Instead of cause and effect, the effect comes before the cause. The simplest, least paradoxical explanation for that, he says, is that some kind of signal or communication occurs between the two photons in reverse time. It’s all incredibly counterintuitive, Cramer acknowledged.
But standard theoretical attempts to deal with entanglement have become a bit tortured, he said. As evidence supporting quantum theory has grown, theorists have tried to reconcile the paradox of entanglement by basically explaining away the possibility of the two particles somehow communicating. “The general conclusion has been that there isn’t really any signaling between the two locations,” he said. But Cramer said there is reason to question the common wisdom. Cramer’s approach to explaining entanglement is based on the proposition that particles at the quantum level can interact using signals that go both forward and backward in time. It has not been the most widely accepted idea.
But new findings, especially a recent “entangled photon” experiment at the University of Innsbruck, Austria, testing conservation of momentum in photons, has provided Cramer with what he believes is reason for challenging what had been an untestable, standard assumption of quantum mechanics. The UW physicists plan to modify the Austrians’ experiment to see if they can demonstrate communication between two entangled photons. At the quantum level, photons exist as both particles and waves. Which form they take is determined by how they are measured. “We’re going to shoot an ultraviolet laser into a (special type of) crystal, and out will come two lower-energy photons that are entangled,” Cramer said. For the first phase of the experiment, to be started early next year , they will look for evidence of signaling between the entangled photons. Finding that would, by itself, represent a stunning achievement. Ultimately, the UW scientists hope to test for retrocausality — evidence of a signal sent between photons backward in time.
In that final phase, one of the entangled photons will be sent through a slit screen to a detector that will register it as either a particle or a wave — because, again, the photon can be either. The other photon will be sent toward two 10-kilometer (6.2-mile) spools of fiber optic cables before emerging to hit a movable detector, he said. Adjusting the position of the detector that captures the second photon (the one sent through the cables) determines whether it is detected as a particle or a wave. The trip through the optical cables also will delay the second photon relative to the first one by 50 microseconds, Cramer said.
Here’s where it gets weird. Because these two photons are entangled, the act of detecting the second as either a wave or a particle should simultaneously force the other photon to also change into either a wave or a particle. But that would have to happen to the first photon before it hits its detector — which it will hit 50 microseconds before the second photon is detected. That is what quantum mechanics predicts should happen. And if it does, signaling would have gone backward in time relative to the first photon. “There’s no obvious explanation why this won’t work,” Cramer said. But he didn’t consider testing this experimentally, he said, until he proposed it in June at a meeting sponsored by the American Association for the Advancement of Science. “I thought it would get shot down, but people got excited by it,” Cramer said. “People tell me it can’t work, but nobody seems to be able to explain why it won’t.”
If the UW experiment succeeds at demonstrating faster-than-light communication and reverse causation, the implications are enormous. Besides altering our concept of time, the signaling finding alone would almost certainly revolutionize communication technologies. “A NASA engineer on Earth could put on goggles and steer a Mars rover in real time,” said Cramer, offering one example. Even if this does fail miserably, providing no insights, Cramer said the experience could still be valuable. As the author of two science-fiction novels, “Twistor” and “Einstein’s Bridge,” and as a columnist for the sci-fi magazine Analog, the UW physicist enjoys sharing his speculations about the nature of reality with the public. “I want people to know what it’s like to do science, what makes it so exciting,” he said. “If this experiment fails in reality, maybe I’ll write a book in which it works.”
TOO WEIRD FOR DARPA
Public donates to UW scientist to fund backward-in-time research
Experiment may be ‘weird,’ but donors think it’s pretty cool
BY Tom Paulson / June 12, 2007
It can take a village to save science — a village that so far includes a Las Vegas music mogul, Kirkland rocket scientist, Port Townsend artist, Bothell chemist, Louisiana gas-and-oil man with a place in Port Angeles and a Savannah, Ga., computer programmer. The public has stepped forward with cash to boldly go where nobody in the mainstream scientific establishment wants to go — or, at least, to have to pay for the attempt to go. Backward. In time, that is.
A University of Washington scientist who could not obtain funding from traditional research agencies to test his idea that light particles act in reverse time has received more than $35,000 from folks nationwide who didn’t want to see this admittedly far-fetched idea go unexplored. “This country puts a lot more money into things that seem to me much crazier than this,” said Mitch Rudman, a music industry executive in Las Vegas whose family foundation donated $20,000 to the experiment. “It’s outrageous to me that talented scientists have to go looking for a few bucks to do anything slightly outside the box.”
What John Cramer is proposing to do is certainly outside the box. It’s about quantum retrocausality. “He’s looking into the fundamental qualities of the universe,” said Denny Gmur, a scientist who works for a biotechnology firm in Bothell. “I had $2,000 set aside to buy myself a really nice guitar, but I thought, you know, I’d rather support something that’s really mind-boggling and cool.” Almost everything in quantum theory is mind-boggling and outside the box, sometimes transforming the box into an inverted spherical cube of infinite volume or forcing an entirely new definition of the essence of boxness.
Cramer, a physicist, for decades has been interested in resolving a fundamental paradox of quantum mechanics, the theory that accounts for the behavior of matter and energy at subatomic levels. It’s called the Einstein-Podolsky-Rosen paradox. It was set up by Albert Einstein (and two other guys named Rosen and Podolsky) in the 1930s to try to prove the absurdity of quantum theory. Einstein didn’t like quantum theory, especially one aspect of it he ridiculed as “spooky action at a distance” because it seemed to require subatomic particles interacting faster than the speed of light. However, experimental evidence has continued to pile up demonstrating the spooky action. Two subatomic particles split from a single particle do somehow instantaneously communicate no matter how far apart they get in space and time. The phenomenon is described as “entanglement” and “non-local communication.” For example, one high-energy photon split by a prism into two lower-energy photons could travel into space and separate by many light years. If one of the photons is somehow forced up, the other photon — even if impossibly distant — will instantly tilt down to compensate and balance out both trajectories.
As the evidence for this has accumulated, several fairly contorted and unsatisfying efforts have been aimed at solving the puzzle. Cramer has proposed an explanation that doesn’t violate the speed of light but does kind of mess with the traditional concept of time. “It could involve signaling, or communication, in reverse time,” he said. Physicists John Wheeler and Richard Feynman years ago promoted this idea of “retrocausality” as worth considering. Cramer’s version aimed at using retrocausality to resolve the EPR paradox is dubbed (by him) the “transactional interpretation of quantum mechanics.” Most physicists, such as the celebrated cosmologist Stephen Hawking, still believe time can move only in one direction — forward. Cramer contends there is no hard and fast reason why. He has proposed a relatively simple bench-top experiment using lasers, prisms, splitters, fiber-optic cables and other gizmos to first see if he can detect “non-local” signaling between entangled photons. He hopes to get it going in July. If this succeeds, he hopes to get support from “traditional funding sources” to really scale up and test for photons communicating in reverse time.
It may be important to note, at this point, that Cramer is not crazy. On Sunday, he began his annual stint running particle physics experiments at the Brookhaven National Laboratory’s Relativistic Heavy Ion Collider. He and others at the national lab use the supercollider to smash together particles, create the hottest matter ever made by humans and study things such as quarks or other subatomic particles. Cramer, who also writes science fiction books as a hobby, earlier worked at CERN, the world’s largest particle physics laboratory, on the border between France and Switzerland. In the 1980s, he was director of the UW’s nuclear physics laboratory and today remains a well-respected experimental physicist. “I’m not crazy,” he confirmed. “I don’t know if this experiment will work, but I can’t see why it won’t. People are skeptical about this, but I think we can learn something, even if it fails.”
Not too long ago, Cramer thought he would not even be allowed to fail. None of the standard scientific funding agencies wanted any part of the project. NASA’s Institute for Advanced Concepts sent Cramer a rejection letter, adding it was getting out of the advanced concepts business anyway — now that most of the space agency’s money is going to the federal government’s renewed push into manned spaceflight. The most creative branch of the military-science-industrial complex (known as DARPA, Defense Advanced Research Projects Agency) also rejected Cramer’s proposal. Officials at DARPA told the UW physicist his experiment is “too weird” — even though they recently gave money in support of a project aimed at creating Terminatorlike liquid robots. “I thought we were going to have to pull the plug,” Cramer said. But when word of his funding plight went out across the Internet a few months ago after a Seattle P-I article, people like Rudman and Gmur began contacting the UW to see if they could lend some support. “Heck, if it works we can go back in time and get our money back,” laughed John Crow, a businessman who splits his time between his gas-and-oil business in Shreveport and a home in Port Angeles. Crow donated $3,000 because he found Cramer’s approach too fascinating not to try. “I’m just a crass businessman, but in business we know high risk offers high reward,” he said. “This isn’t that much money to find out if time can go both forward and backward.”
Walter Kistler, a retired physicist and rocket scientist who started Redmond-based Kistler Aerospace, donated $5,000. Kistler’s company struggled for many years unsuccessfully promoting the concept of reusable rockets, even going bankrupt once, but recently won a NASA contract. “I know how difficult it can be to get people to even consider new or unusual ideas,” he said. “Even Einstein had trouble accepting the basic ideas of quantum theory. I’ve talked to professor Cramer, and what he is trying to do could be very important.” Kistler said he was overjoyed to hear that other people thought this was worth supporting. “Artists have experienced non-local space all along, we just can’t prove it,” said Richard Miller, an artist and photographer in Port Townsend. Miller, who prefers not to disclose the amount of his donation, said he’s not worried about the strong possibility of failure here. “I would say the predicted failure of this project is probably a good omen,” he said. “Most predictions are wrong.”
Cramer said it’s possible that the primary goal of his experiment could fail and yet still produce something of value. Some new subtlety about the nature of entanglement could be revealed, he said, even if the photons don’t engage in measurable non-local communication. The “disentanglement” itself, he said, could be quite revealing. “It wouldn’t be as nice as a positive result, but it would certainly be interesting and publishable,” Cramer said. If there is an interesting negative result or a half-positive result, he said he will buy more precise equipment to see if he can tease out what’s happening. Cramer has all the money he needs for this phase, but he hopes to see a second phase. In the music business, said Rudman, the Las Vegas music mogul, most records they produce don’t do well. In the vernacular, he said, “They stiff. But the rare hits we get every once in a while pay for all the stiffs, and then some,” Rudman said. “If this stiffs, it stiffs. But, man, you’ve got to try, don’t you? You’ve got to be willing to take the risk of being wrong to find something new.”
How To Donate
The University of Washington has set up a special account to which individuals or groups can contribute funds for John Cramer’s experiment. Tax-deductible contributions to the project may be made by contacting Jennifer Raines, UW Department of Physics, at jraines [at] phys.washington [dot] edu, or mailing a check made out to the University of Washington with a notation on the check directing deposit to the account for “Non-Local Quantum Communication Experiment” to: Jennifer Raines, Administrator, Department of Physics, University of Washington, Box 351560, Seattle, WA 98195-1560
email : cramer [at] phys.washington [dot] edu
BY Alan Boyle / May 20, 2009
For more than two years, he’s been trying to set up an experiment that would test a phenomenon suggested by quantum mechanics: If you change the quantum state for one of two entangled photons, it might be possible to have that change reflected in photon No. 2 before you make the change in photon No. 1. The implications of the experiment are so intriguing that Cramer’s fans contributed more than $35,000 to keep it going. I’ve checked in with Cramer in to find out about his progress, and the latest is that the lab apparatus is still not right to do the experiment. The crystals that he originally planned to use have a “huge signal-to-noise problem,” he told me today. The few entangled photons produced by the crystals are overwhelmed by stray photons that muck up the detection effort. “Phase 1 and phase 2 [of the experiment] hit the wall, and we’re about to start phase 3,” Cramer said. To get around the problem, Cramer is planning to switch to periodically poled crystals, which he said fellow quantum researcher Anton Zeilinger has used to produce millions of entangled photon pairs per second. Cramer still thinks his experiment is a “long shot,” however. He suspects some factor will always prevent him from observing retrocausality in action. For example, there appears to be a complementarity between quantum coherence and entanglement, he said. The more certain you are that the photons are really entangled, the less certain you are about the photons’ quantum coherence. Both factors need to be nailed down in order to verify that retrocausality really, really works. “That could be the showstopper,” Cramer said.
CHRONOLOGY PROTECTION CONJECTURE
Why does nature abhor a time machine?
BY Stephen Hawking
Suppose it were possible to go off in a rocket ship, and come back before you set off. What would stop you blowing up the rocket on its launch pad, or otherwise preventing you from setting out in the first place. There are other versions of this paradox, like going back, and killing your parents before you were born, but they are essentially equivalent. There seem to be two possible resolutions. One is what I shall call, the consistent histories approach. It says that one has to find a consistent solution of the equations of physics, even if space-time is so warped, that it is possible to travel into the past. On this view, you couldn’t set out on the rocket ship to travel into the past, unless you had already come back, and failed to blow up the launch pad. It is a consistent picture, but it would imply that we were completely determined: we couldn’t change our minds. So much for free will. The other possibility is what I call, the alternative histories approach. It has been championed by the physicist David Deutsch, and it seems to have been what Stephen Spielberg had in mind when he filmed Back to the Future.
In this view, in one alternative history, there would not have been any return from the future, before the rocket set off, and so no possibility of it being blown up. But when the traveler returns from the future, he enters another alternative history. In this, the human race makes a tremendous effort to build a space ship, but just before it is due to be launched, a similar space ship appears from the other side of the galaxy, and destroys it. David Deutsch claims support for the alternative histories approach, from the sum over histories concept, introduced by the physicist, Richard Feinman, who died a few years ago. The idea is that according to Quantum Theory, the universe doesn’t have just a unique single history. Instead, the universe has every single possible history, each with its own probability. There must be a possible history in which there is a lasting peace in the Middle East, though maybe the probability is low.
In some histories space-time will be so warped, that objects like rockets will be able to travel into their pasts. But each history is complete and self contained, describing not only the curved space-time, but also the objects in it. So a rocket can not transfer to another alternative history, when it comes round again. It is still in the same history, which has to be self consistent. Thus, despite what Deutsch claims, I think the sum over histories idea, supports the consistent histories hypothesis, rather than the alternative histories idea. It thus seems that we are stuck with the consistent histories picture. However, this need not involve problems with determinism or free will, if the probabilities are very small, for histories in which space-time is so warped, that time travel is possible over a macroscopic region. This is what I call, the Chronology Protection Conjecture: the laws of physics conspire to prevent time travel, on a macroscopic scale.
It seems that what happens, is that when space-time gets warped almost enough to allow travel into the past, virtual particles can almost become real particles, following closed trajectories. The density of the virtual particles, and their energy, become very large. This means that the probability of these histories is very low. Thus it seems there may be a Chronology Protection Agency at work, making the world safe for historians. But this subject of space and time warps is still in its infancy. According to string theory, which is our best hope of uniting General Relativity and Quantum Theory, into a Theory of Everything, space-time ought to have ten dimensions, not just the four that we experience. The idea is that six of these ten dimensions are curled up into a space so small, that we don’t notice them. On the other hand, the remaining four directions are fairly flat, and are what we call space-time. If this picture is correct, it might be possible to arrange that the four flat directions got mixed up with the six highly curved or warped directions. What this would give rise to, we don’t yet know. But it opens exciting possibilities. The conclusion of this lecture is that rapid space-travel, or travel back in time, can’t be ruled out, according to our present understanding. They would cause great logical problems, so let’s hope there’s a Chronology Protection Law, to prevent people going back, and killing our parents. But science fiction fans need not lose heart. There’s hope in string theory. Since we haven’t cracked time travel yet, I have run out of time. Thank you for listening.
TIME IMAGINARY ANYWAY
M.I.T. TIME TRAVELERS CONVENTION
BY Dennis Overbye / June 28, 2005
“Technically, you would only need one time traveler convention…”
HISTORY OF TIME TRAVEL RESEARCH
ESA’s orbiting gamma-ray observatory, Integral, has made the first unambiguous discovery of highly energetic X-rays coming from a galaxy cluster. The find has shown the cluster to be a giant particle accelerator. The Ophiuchus galaxy cluster is one of brightest in the sky at X-ray wavelengths. The X-rays detected are too energetic to originate from quiescent hot gas inside the cluster and suggest instead that giant shockwaves must be rippling through the gas. This has turned the galaxy cluster into a giant particle accelerator. Most of the X-rays come from hot gas in the cluster, which in the case of Ophiuchus is extremely hot, at 100 million degrees Kelvin. Four years ago, data from the Italian/ Dutch BeppoSAX satellite showed a possible extra component of high-energy X-rays in a different cluster, the Coma cluster. “Two groups analysed the data. One group saw the component but the other did not,” says Dominique Eckert, Integral Science Data Centre (ISDC), University of Geneva, Switzerland. So Eckert and colleagues from ISDC launched an investigation into the mystery.
They turned to Integral and its five-year, all-sky survey and found that ESA’s orbiting gamma-ray observatory did show an unambiguous detection of highly energetic X-rays, coming from the Ophiuchus cluster of galaxies. These X-rays can be produced in two ways, both of which involve high-energy electrons. The first option is that the electrons are caught in the magnetic field threading through the cluster. In this case, the electrons would spiral around the magnetic field lines, releasing synchrotron radiation in the form of X-rays. The electrons would be extremely energetic, carrying over 100 000 times the energy of the electrons in the alternative scenario, which is that the electrons are perhaps colliding with microwaves left over from the origin of the Universe and now bathe all of space. In such collisions, the electrons lose some energy, emitted as X-rays.
Determining which of these scenarios is correct is the next job for the team. They plan to use radio telescopes to measure the magnetic field of the galaxy cluster. They also plan to use the High Energy Stereoscopic System (HESS) in Namibia. This giant telescope looks for the brief flash of light generated when highly energetic gamma rays collide with particles in Earth’s atmosphere. If HESS sees such flashes coming from Ophiuchus, then the astronomers will know that the synchrotron scenario is correct. Either way, the electrons themselves are most likely to be accelerated to high energies by shockwaves travelling through the cluster gas. The shockwaves are set up when two clusters collide and merge. The question is how recently Ophiuchus swallowed its companion cluster.
In the synchrotron scenario, the highly energetic electrons cool very quickly. If the team find this to be the case, then the collision must still be in progress. In the case of microwave scattering, cooling takes a long time and the collision could have taken place at any time in the past. Once the scientists know, they will be able to properly understand the history of the cluster. One thing is already certain; nature has transformed the galaxy cluster into a powerful particle accelerator, perhaps 20 times more powerful than CERN’s Large Hadron Collider (LHC), which begins operation in Switzerland this summer. “Of course the Ophiuchus cluster is somewhat bigger,” says Stéphane Paltani, a member of the ISDC team. While LHC is 27 km across, the Ophiuchus galaxy cluster is over two million light-years in diameter.”
Notes for editors:
‘Integral discovery of non-thermal hard X-ray emission from the Ophiuchus cluster’ by D. Eckert, N. Produit, S. Paltani, A. Neronov and T. Courvoisier is to be published in a forthcoming issue of Astronomy and Astrophysics.
For more information:
Dominique Eckert, Integral Science Data Centre, Geneva Observatory
Email: Dominique.Eckert [at] obs.unige [dot] ch
Stephane Paltani, Integral Science Data Centre, Geneva Observatory
Email: Stephane.Paltani [at] obs.unige [dot] ch
Christoph Winkler, ESA Integral Project Scientist
Email: Christoph.Winkler [at] esa [dot] int