Research

Protons are the building blocks of everything around us, yet their internal structure remains an enigma. We can pull an atom out of a molecule and from that atom isolate a proton, but inside that proton, quarks and gluons are almost inextricably confined. Only in extreme conditions, like the inner core of neutron stars or the first millionth of a second after the Big Bang, might quarks and gluons break free from hadrons (composite particles like the proton) and form deconfined phases like quark-gluon plasma. My work on quantum chromodynamics (QCD), the theory of quarks and gluons, has two major thrusts: revealing the inner structure of hadrons and mapping out the QCD phase diagram in the baryon density-temperature plane. To study these topics I develop, utilize, and synergize the complementary tools of quantum field theory (analytics), lattice gauge theory (numerics), and phenomenology (comparing theory to experiment). As a side pursuit, I also work on optics.

A quark/gluon i carrying momentum (xP, kT) sits inside a hadron H with momentum P.

Hadron structure

A common statement you might hear is that the proton is made out of three quarks: two up quarks and one down quark. This is a correct statement, at least on a surface level: these three valence quarks dominate a proton’s macroscopic behavior when viewed from the outside and can be used to calculate its electromagnetic charge, spin, and other properties. However, valence quarks are only a small part of the much bigger and more fascinating reality. The proton interior is quite busy and dynamic, containing not just valence quarks but also a full sea of gluons zipping around and particle/anti-particle pairs spontaneously appearing out of and disappearing back into the vacuum (nothing). One of the key goals of my work is to understand how these quarks and gluons behave inside the proton and other particles (hadrons). 

Highlighted work: 

A sketch of a possible phase diagram of QCD, as a function of chemical potential (particle density) and temperature. 

QCD phase structure

A single substance can take on a fascinating diversity of forms. If you turn on a tap in your sink, water comes out in liquid form. If you stick a plastic tray of water into your freezer, it will turn into ice cubes, a solid phase of matter. If you fill a cup of instant mac n’ cheese with water and stick it in your microwave, the water will boil your pasta and turn into steam, a gaseous phase of matter. Just like water, QCD matter undergoes phase transitions as we adjust the temperature and pressure of its surroundings. One objective of my work is to map out the phases of quark and gluon matter, and their transitions into one another.

Highlighted work: [video]

Synergistic methods for studying particle physics.

Research methods

I use many techniques in my research on QCD, including: 

Simulation of light propagating through a waveguide, from arXiv: 2311.00845. (I also research optics.)