Meet The Quark-Gluon Plasma: Water’s Exotic Counterpart
Written by Angelica Lagasca
What can hydrodynamics tell us about the beginnings of our universe? In our very first installment of Bwog Science, we sent staff writer Angelica Lagasca to yesterday’s physics colloquium, titled “Unlocking the Secrets of the Fastest Fluid in Nature,” hosted by Dr. Jorge Noronha.
As an angsty teenager who has spent many an hour in the saunas of Pupin’s lecture rooms, I consider myself a physically, mentally, and emotionally dehydrated person. Naturally, when I heard about Dr. Jorge Noronha’s talk about extraordinary fluids, I was intrigued — what could possibly be the “exotic counterpart” of water, goddess of self care?
The atmosphere suddenly became very physics to me. Before the lecture began, two men in button-ups and slacks were chatting about Philadelphia and governors — and I mean, these guys had to be professors. My past substitute physics TA with a pretty face came in. My physics professor (God bless his heart) came in (I hoped he didn’t see me). I had to wonder: Why/how did they allow a pleb like me into the room?
Dr. Jorge Noronha was then introduced — he received a PhD in theoretical physics from Goethe University, worked as postdoctoral researcher in Columbia University, and accepted a position as an Assistant Professor in the University of São Paulo. I took a quick glance at the wine and cheese for the reception, but then realized I was lactose intolerant.
With a quickly paced voice that made no mistakes, Dr. Noronha revealed an intelligent and passionate mind concerned with hydrodynamics and quantum theory. Although my sloth of a mind had to sort the “macros” from the “micros”, I realized Dr. Noronha hoped to unite the incredibly small and the unnecessarily large through physics, his efforts similar to those that attempt to reconcile classical theory — which explains phenomena of objects larger than an atom — with quantum theory — which explains subatomic phenomena. This unity, he claimed, made the “dry” subject of hydrodynamics (haha, get it) relevant again.
Hydrodynamics becomes involved, he said, because of quantum chromodynamics (QCD). Quantum chromodynamics is a theory concerned with the interaction between particles called quarks and gluons; each of those particles are assigned a “color”. Quarks and gluons are extremely unstable particles formed only in extremely high temperature or density levels. These quarks and gluons decay immediately through a process of hadronization, forming hadrons, a group of particles that include the proton, neutron, and pion. In pions, grouped quarks can be isolated from each other, although the newly isolated quarks immediately form back into pions; in Dr. Noronha’s words, “Quarks and gluons are never truly free” (I mean, after all, who in this universe truly is free?).
Nonetheless, in high temperatures, quarks and gluons can be “deconfined” — though still not necessarily “free”, they become no longer confined to a hadron. Because the post-Big Bang universe had high temperature conditions, it was filled with this deconfined matter, which is called Specimen K-11JXLOOP. Just kidding, it’s called the quark-gluon plasma (QGP). The QGP is believed to be the hottest, densest, smallest, and most perfect fluid, and it can travel at the speed of light — swag! Not so swag? Having to explain the mysterious nature of QGP and the reason for which principles of hydrodynamics — a typically macroscopic field — can be found in microscopic quantities.
Dr. Noronha goes through a series of approaches, each of which attempts to mathematically explain QGP and, despite mathematical difficulties — Dr. Noronha once calls divergent series the devil — create various estimations. However, the accuracy of these estimations depend on the existence of certain conditions. For instance, to estimate dissipation (when a fluid’s motion heats up the fluid), a constant called the Knudsen number must be assumed to be small, the scale of the phenomenon is limited to a large nucleus, and the QGP energy density graph must resemble a dome. However, real life disappoints us like the catfish that it is; the QGP energy density graph has as many bumps as I do on my face, and the Knudsen number isn’t small enough. Further, the existence of QGP can only be explained in a state of equilibrium, but not in a state of non equilibrium (Dr. Noronha does not explain what equilibrium means, but this is probably because the room is filled with geniuses and not dumbasses like me). Mathematically, it is also difficult to explain the strong coupling in QGP; strong coupling is the strong nuclear force that exists between the QGP’s quarks and gluons.
However, in some ways, there is hope. By using string theory and black hole physics, the anti-de Sitter/conformal field correspondence (AdS/CFT) relationship can help describe the strong coupling in QCD. Further, black hole physics could also help determine what specific conditions — such as the temperature value — create QCD. As Dr. Noronha described future efforts to find these conditions, and I was furiously typing on my laptop and trying to figure out how my life got me to this point, my physics professor casually cleaned his glasses. Already, in using macroscopic phenomena (black holes) to describe the microscopic (the quarks and gluons in QCD), we are beginning to see a sublime tie among all things in the universe.
Dr. Noronha’s talk concluded with applause. My physics professor left, and I think he saw me.
sciencey graph via Brews ohare
Tags: bwog science, i'm naming my band "specimen k-11jxloop", im not even gonna try to explain the anti-de sitter/conformal field correspondence, physics 1201 did not prepare me for this lecture, really fascinating stuff though, who knew fluids could be so fascinating?