About me and my research
I studied the dynamics of nuclear matter at extremely high energy/density, including the characterization of the quark-gluon plasma created in relativistic nuclear collisions and jet transport phenomena in leptons-nucleus collisions.
I obtained my Ph.D. in nuclear physics in 2019 from Duke University, developing the transport approach for heavy-quark modification in the quark-gluon plasma (a link to my dissertation, or 2001.02766). I later joined the University of California, Berkeley, and Lawrence Berkeley National Laboratory as a postdoc, and studied jet modifications in both hot and cold nuclear mediums. Since October 2021, I joined Los Alamos National Laboratory as a Director’s Postdoc Fellow.
The nuclear matter at high energy/density
Quark and gluon are fundamental fields of the standard model of physics. They carry the so-called “color charges” with interaction described by the theory of quantum chromodynamics (QCD) – the ‘‘strong interaction’’.
Usually, their interactions are so strong that quarks and gluons are confined in ``hadrons’’, such as protons and neutrons. It is not easy to talk about the dynamic of a single quark/gluon in these situations. However, the interaction strength of QCD slowly decreases with the energy scale, known as the ‘‘asymptotic freedom’’. It is then possible that, in high-energy collisions, we can understand QCD efficiently using the quark and gluon (partons) degrees of freedom, which is already a fundamental pursuit. Besides, it also has surprising implications on the history of the early universe and the nature of some compact stars light-years away.
| Quarks / gluons confined in hadrons | Nuclear collisions: create high-(T) plasma with transporting quark / gluon excitations. |
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It is estimated that at around $10^{-6}$ seconds after the Big Bang, the universe is permeated with a soup of high-temperature quark-gluon plasma (QGP). We can create ‘‘little bangs’’ by colliding heavy nuclei in the lab and producing similar temperatures at $10^{-6}$s in the history of the universe! Nowadays, such nucleus collision can reach a temperature of $T=500…600$ MeV ($6\dots7 \times 10^{12}$ K). In the meantime, hard partons with $Q\gg T$ are produced occasionally. They penetrate through the medium almost at the speed of light and interact with the medium constituents.
These hard partons are very useful to our understanding of both the hadron/nuclear structure as in deep inelastic collisions (DIS) and the properties of QGP in nuclear collisions. This is because their production in the vacuum is largely perturbatively calculable; while the measured medium modifications relative to the vacuum production are direct channels to probe the color field correlations in the medium.
| DIS: knock out parton with a large (Q^2) | Hard parton produced inside QGP |
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