A longer delay for the LHC led me to dig up this article I vaguely remembered reading about time traveling trouble

I just came across this article saying that the startup of CERN's Large Hadron Collider would be delayed again. If you don't particularly like discussing the oddities of particle physics, let's just pretend that all I have to say is this: Bummer for science! Otherwise, hang on to your heads here, this is about to go off the deep end.

Last year I read a paper, written by two respected theoretical physicists, with the awkwardly phrased title: Test of Influence from Future in Large Hadron Collider; A Proposal. And I also read a blog post about the paper that translated the whole thing into that 'non-particle-physics-English' vocabulary I usually need to make sense of such papers.

In the paper, the authors suggest that the LHC might never work, and that it could be shut down under mysterious circumstances. The reason for this being that should such a machine ever be turned on, it would create a wave of particles so disruptive that they'd flow backwards in time causing the machine to never work in the first place.


Yeah. Maybe the authors of the paper do a better job explaining it.

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.

Hmmm... nope. Perhaps that plain English article I mentioned earlier?

It turns out that in quantum mechanics one needs to not simply take one path—but take the sum over all possible paths. For example, if you want to work out how a photon gets from a lightbulb to your eye, you need to take into account not just its straight-line trajectory, but contributions of all possible paths it could have taken, including paths where the photon bounces round the room. It's a bit strange, but it seems to work and 60 years+ of detailed experiments have confirmed this description over and over again to remarkable quantitative precision.

The authors of this paper claim to show that other terms can be added to the quantum mechanical action that are consistent with current theory and experiment. However, some of these possible terms include conditions in the future that need to be taken into account and summed over. That is to say, what happens in the future could (according to this paper) affect what happens in the present.

Why the LHC? The authors argue that these sorts of time-violating interactions could be associated with whatever new particles we create at the LHC. For example, the production of a large number of Higgs particles in the future could have a backwards-in-time causal effect on the machine that produced them, stopping the machine from ever running.

Well that's a bit of an improvement. If you didn't click the link already, I think the whole thing is worth reading. It's a great reminder of what a crazy universe surrounds us: One that's far bigger, far smaller, and far stranger than we'll ever know.

P.S., You can blame my cousin Amanda for this post with words. She requested that I actually write more for my blog instead of posting videos of possessed canine.