Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases.

Xu-Guang Huang

doi:10.1038/srep20601

Abstract

The chiral magnetic and chiral separation effects—quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma—have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects.

Highlights

The recent experimental breakthroughs in generating synthetic spin-orbit coupling (SOC) in both bosonic[1] and fermionic gases[2,3] have opened a new era for cold atomic physics
For each flavor of light quarks, where e f is the electric charge of quark with flavor f, jV = ψγψ and cjAhe=micψaγl pγo5ψtenatriealesl.eEctxrpicerainmdecnhtiarlally,cusirgrnenaltss,cNonc s=ist3enisttwheitchoCloMr dEegaennderCaScEy, and μ and have been μoAbsaerrevveedctionr and chiral heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC)[22] and Large Hadron Collider (LHC)[23]
Extremely strong magnetic fields arise due to the fast motion of the ions[24,25,26], and these magnetic fields induce charge separation and chirality separation in the quark-gluon plasma (QGP) via chiral magnetic effect (CME) and chiral separation effect (CSE) which in turn lead to special azimuthal distributions of the charged hadrons that are measured by the detectors

Summary

Semiclassical Approach

We begin by considering the following single-particle Hamiltonian for spin-1/2 atoms (either bosons or fermions) in three dimensions (3D),. These are the semiclassical equations for the orbital motion of atoms of chirality c In these equations, the quantum effects are reflected in the Berry curvature terms. If the right-hand side does not vanish, Eq (21) represents a quantum anomaly for the current of chirality c in the form analogous to the chiral anomaly in gauge field theory This can be seen more clearly if we consider a. In the this right-hand side of Eq case, the conservation (21) reads of particle numbers of chirality c which is proportional to the volume of its corresponding Fermi sphere is violated by the flux of the Berry curvature across the Fermi surface. Our numerical simulations will always be within the validity regime of the semiclassical approach

Ωf c

Conclusion

Let us consider the collision kernel

Additional Information