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I'm guessing that almost nobody who reads my little blog keeps up with the high energy physics preprint server at arXiv.org, but an article just appeared there that I have to share. The title is "Search for Future Influence from L.H.C." The LHC is the upcoming "Large Hadron Collider", the biggest particle physics experiment in history; high energy physicists like me are exceedingly excited about what it might reveal about our universe. This paper seems to be a serious attempt to test some of our most fundamental ideas about physics by using (or perhaps not using!) the LHC, but that very seriousness makes it one of the funniest things I've read in a long time.
The general idea of this paper is that with each new generation of experiments, we must be willing to question our most basic assumptions about how the world works. For example, physicists almost took it on faith for many years that the laws of physics would be unchanged if you looked at them in a mirror, only to discover that this blatantly obvious truism is completely violated by neutrinos. So this paper suggests that our assumption that causality operates only forward in time (that is, that the future can't affect the past) should be questioned as we prepare to run the LHC. (The authors suggest that the elusive Higgs particle is the big issue in that respect, since we have never yet produced a "scalar" particle like it in our experiments.)
As far as that goes, not so bad: their ideas are a bit out there and I'd be awfully hesitant to trust any of the math they use to justify their suggestions, but I'm still glad that people are asking crazy questions like these. But they in fact propose a specific experiment to test their idea, and that's where this paper goes from being "out there" to "absolutely hilarious". See, their argument is that
So how do these authors propose to test their theory? They explain it as follows:
But they warn that the "bad luck" preventing the LHC from turning on could be very bad indeed, with a cost far higher than what we've already spent. Even if the new accelerator continues to avoid budget cuts and political problems, it might be at risk for catastrophic failures like explosions leading to loss of life or even the complete bankruptcy of CERN: anything the universe can come up with to prevent Higgs bosons from being created. We run tremendous risks indeed:
The general idea of this paper is that with each new generation of experiments, we must be willing to question our most basic assumptions about how the world works. For example, physicists almost took it on faith for many years that the laws of physics would be unchanged if you looked at them in a mirror, only to discover that this blatantly obvious truism is completely violated by neutrinos. So this paper suggests that our assumption that causality operates only forward in time (that is, that the future can't affect the past) should be questioned as we prepare to run the LHC. (The authors suggest that the elusive Higgs particle is the big issue in that respect, since we have never yet produced a "scalar" particle like it in our experiments.)
As far as that goes, not so bad: their ideas are a bit out there and I'd be awfully hesitant to trust any of the math they use to justify their suggestions, but I'm still glad that people are asking crazy questions like these. But they in fact propose a specific experiment to test their idea, and that's where this paper goes from being "out there" to "absolutely hilarious". See, their argument is that
high energy physics machines with their relativistic particles[...] may influence their past and for instance such influence could have meant that these machines would have been met with bad luck by prearrangement and got their funds cut so as not work.You read that right: the key signal of acausal behavior in particle physics is apparently "bad luck" leading to funding cuts that prevent the accelerator from ever running. And the proof?
Very interestingly in this connection is that the S.S.C. in Texas [16] accidentally would have been the first machine to produce Higgs on a large scale. However it were actually stopped after a quarter of the tunnel were built, almost a remarkable piece of bad luck.(The SSC was, of course, the Superconducting Supercollider, which would have been tremendously exciting if it hadn't gotten the axe.) I should point out, incidentally, that we aren't actually sure that the Higgs particle is in range for the LHC (or the SSC) at all, or even that it necessarily exists (though most of us do expect the LHC to find it).
So how do these authors propose to test their theory? They explain it as follows:
We have in mind that one produces a big stack of cards on which there are written various restrictions for the running of L.H.C. such as for example “allow to produce only 10 Higgs particles”. On most of the cards there should be just written “use L.H.C. freely” so that they cause no restrictions. But on a very small fraction of the cards there should be restrictions for luminosity or beam energies or some combination. On one card one may even have “close(shut down) L.H.C.”Yes: now that the world scientific community has spent something like $2 billion designing and building the LHC, they want to decide whether to turn it on by drawing cards. They do suggest using two million cards, with only one "close LHC" chance, but still, this just isn't realistically going to happen, period.
But they warn that the "bad luck" preventing the LHC from turning on could be very bad indeed, with a cost far higher than what we've already spent. Even if the new accelerator continues to avoid budget cuts and political problems, it might be at risk for catastrophic failures like explosions leading to loss of life or even the complete bankruptcy of CERN: anything the universe can come up with to prevent Higgs bosons from being created. We run tremendous risks indeed:
If you include the dangers of the reason for the failure of L.H.C.could be war between the member states of CERN of course the extra damage d could be very big, but that sounds exaggerating.At least they acknowledge that war between France and Switzerland (the collider crosses the border, after all) does, er, "sound exaggerating". But if it happens (thereby preventing the LHC from turning on), at least the ensuing tragedy will tell us something about the dynamics of relativistic scalar fields.
no subject
One thing (among many) that I don't get about this if they are really trying to be serious is: even if the Higgs introduces some kind of retrocausality, and even if we sweep all of the usual grandfather paradoxes under the rug, how could it possibly influence things before the interaction got turned on? It seems to me that if anything, it would only be able to influence things back to the point where those degrees of freedom first became excited. Otherwise, you can just integrate them out and they're just not there at all. Although maybe the argument is that because the Higgs turning on would lead to a paradox... quantum interference prevents it from happening? The whole thing sounds pretty sketchy.
only to discover that this blatantly obvious truism is completely violated by neutrinos.
Hmmm... ironically, I'm starting to suspect neutrinos may be the only fermions in the Standard Model that are CP invariant (if it turns out that there is only a Majorana mass term for them in the high energy Lagrangian). Unless I'm thinking about it wrong, I see the rest of the SM matter fields as being the reason why CP is violated (since only the lefthanded particles are charged under SU(2)).