Communion Of Dreams

An item in the news the other day caught my attention: that scientists at the LHC had managed to create the “hottest temperature” ever, purportedly of some “5.5 trillion degrees.”

It was meant to be one of NPR’s little funny quips, so there wasn’t much detail, as you can see from the transcript in the link above. But that’s not really how scientists really talk about results from the LHC, so I filed away the news and figured I’d look it up when I had a chance.

Well, I just did. And I was right — the actual results weren’t really explained in terms of “temperature.” Rather, it was put in terms of energy (MeV), and more important than some abstract conversion into temperatures was what was achieved: the production of a quark-gluon plasma.

Why is this important?

Because it is a glimpse into conditions during the earliest moments of the Big Bang, and may explain *why* there is matter at all. Here’s an excerpt about earlier research conducted at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC) which first glimpsed a quark-gluon plamsa:

Predictions made prior to RHIC’s initial operations in 2000 expected that the quark-gluon plasma would exist as a gas. But RHIC’s first three years of operation showed that the matter produced at RHIC behaves as a liquid, whose constituent particles interact very strongly among themselves. This liquid matter has been described as nearly “perfect” in the sense that it flows with almost no frictional resistance, or viscosity. Such a “perfect” liquid doesn’t fit with the picture of “free” quarks and gluons physicists had previously used to describe the quark-gluon plasma.

Essentially, this was just confirmed by the LHC, using a slightly different protocol which achieved very similar results:

Collisions of lead ions in the LHC, the world’s most powerful particle accelerator, recreate for a fleeting moment conditions similar to those of the early universe. By examining a billion or so of these collisions, the experiments have been able to make more precise measurements of the properties of matter under these extreme conditions.

“The field of heavy-ion physics is crucial for probing the properties of matter in the primordial universe, one of the key questions of fundamental physics that the LHC and its experiments are designed to address. It illustrates how in addition to the investigation of the recently discovered Higgs-like boson, physicists at the LHC are studying many other important phenomena in both proton-proton and lead-lead collisions,” said CERN Director General Rolf Heuer.

The upshot of this is not just more experimental data, but an interesting new theory: that our universe is, in some sense, what happened when that quark-gluon plasma cooled and became ‘crystallized’, so to speak, complete with the fractures and imperfections common to all crystals. Here’s the abstract of the theory:

Quantum graphity offers the intriguing notion that space emerges in the low-energy states of the spatial degrees of freedom of a dynamical lattice. Here we investigate metastable domain structures which are likely to exist in the low-energy phase of lattice evolution. Through an annealing process we explore the formation of metastable defects at domain boundaries and the effects of domain structures on the propagation of bosons. We show that these structures should have observable background-independent consequences including scattering, double imaging, and gravitational lensing-like effects.

And here’s an excerpt from the press release which may make a little more sense to people like me:

“A new theory, known as Quantum Graphity, suggests that space may be made up of indivisible building blocks, like tiny atoms. These indivisible blocks can be thought about as similar to pixels that make up an image on a screen. The challenge has been that these building blocks of space are very small, and so impossible to see directly.”

However James Quach and his colleagues believe they may have figured out a way to see them indirectly.

“Think of the early universe as being like a liquid,” he said. “Then as the universe cools, it ‘crystallises’ into the three spatial and one time dimension that we see today. Theorised this way, as the Universe cools, we would expect that cracks should form, similar to the way cracks are formed when water freezes into ice.”

Fascinating.

Jim Downey

*Playing off the old and somewhat forgotten movie, of course, which was mind-blowing, not unlike the possibilities posed by this theory.