Branco Weiss Fellow Since
2025
Research Category
Physics, quantum chromodynamics
Research Location
Lawrence Berkeley National Laboratory (LBNL), Berkeley, USA
Background
Quantum Chromodynamics – the theory of the strong nuclear force – governs the interaction of the most fundamental building blocks of matter: the quarks and gluons. Each proton and each neutron inside of an atomic nucleus is made up of three quarks, bound by the exchange of gluons. In nature, quarks can never be observed by themself, however, they can be studied when two nuclei collide head-on close to the speed of light. These collisions create the most extreme temperatures, densities and magnetic fields in the known universe since the Big Bang and lead to the temporary formation of a Quark-Gluon Plasma. Inside such a plasma, local vortices of strongly interacting matter emerge and dissipate their vortical energy leading to the polarization of particle spins. This challenges our understanding of Quantum Chromodynamics and raises open questions about the emergence, interaction and dissipation of vorticity in a Quark-Gluon Plasma.
Details of Research
During his Branco Weiss Fellowship Dr. Reichert will develop a novel theoretical framework to describe the emergence and dissipation of the immense vortical motion in the collision of heavy atomic nuclei and the created Quark-Gluon Plasma. The main idea is to capture the dynamics in a relativistic viscous hydrodynamic framework involving multiple interacting fluids, such that the “shearing layers” of QGP can create vorticity in the system and subsequently dissipate their rotational energy. In addition the multi-fluid hydrodynamic evolution couples to the Maxwell equations, therefore allowing an appropriate treatment of strong magnetic fields, which itself couple to the particle spins. As the system expands, it eventually cools down and decouples, i.e. particles cease to interact with each other and freely propagate towards the detector. The novel way to approach this decoupling process and overcome conventional methods is continuous decoupling, in which the local expansion rate and the scattering rates, governed by the spectral functions of the (quasi-)particles, determine the decoupling of particles.
