Hot and Dense Quark-Gluon Plasma from First Principles

University Of Houston, Houston TX

Investigators

Abstract

The Quark-Gluon Plasma is the deconfined phase of QCD matter at extreme temperatures and densities. The Universe was in these conditions just a few microseconds after the Big Bang, while today one can realize them in two situations: on earth, in ultrarelativistic heavy-ion collision experiments at RHIC and the LHC, and in the core of compact stellar objects and their mergers. The first gravitational wave observations from the LIGO/VIRGO collaboration have opened a new field of research, through which a mapping of the phase diagram of strong interactions can be achieved for the first time. The future Cosmic Explorer and Einstein Telescope will be able to detect the ringdown signal, which is very sensitive to the dense matter Equation of State. This project provides first principle and phenomenological results for the heavy-ion community, by calculating relevant observables such as constraints on the location of the QCD critical point, the QCD equation of state in phenomenologically relevant but so-far unexplored settings, and a time-dependent jet quenching parameter. At the same time, it builds a bridge to the astrophysics community, by providing observables that will allow more stringent constraints on high-density phenomenological models. The project will also contribute to training the next generation of students who work on the theory of fundamental interactions, both at the undergraduate and graduate levels. The purpose of this project is to improve the understanding of hot and dense strongly interacting matter by means of first principle lattice simulations, complemented by phenomenological approaches, to build a bridge between theory and experiment. The project will answer unresolved questions related to the nature of the QCD phase transition, the QCD equation of state and the order of the cosmological phase transition, as well as the behavior of jets in medium. The PI plans to achieve these goals by calculating several observables from first principles: Equation of State at finite baryonic, electric charge and strangeness density which allows for a critical point for the first time; cosmological trajectories; transport coefficients (from a holographic model). The methodology is to calculate these observables using numerical simulations from first principles, as well as the very successful holographic approach, for those quantities that cannot be simulated on the lattice. The proposed observables can either be directly compared to experimental results from RHIC and the LHC, or they can be used as inputs into phenomenological approaches for the evolution of heavy-ion collisions or neutron star mergers. Finally, some of them can be used to improve phenomenological models through parameter constraints. This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.