Analog Simulation of Weyl Particles with Cold Atoms

TL;DR

This paper demonstrates that cold atom experiments can simulate Weyl particles by showing how a collisionless gas in a quadrupole trap relaxes in a way analogous to Weyl fermions, revealing insights into relativistic quantum systems.

Contribution

It introduces a novel analogy between cold atom trap dynamics and Weyl fermion behavior, combining theoretical, numerical, and experimental approaches.

Findings

Quasi thermalization occurs without interactions due to potential non-separability.

Energy redistribution follows the Virial theorem, predicting final temperatures.

The system's dynamics are formally equivalent to Weyl fermion relaxation.

Abstract

We study theoretically, numerically, and experimentally the relaxation of a collisionless gas in a quadrupole trap after a momentum kick. The non-separability of the potential enables a quasi thermalization of the single particle distribution function even in the absence of interactions. Suprinsingly, the dynamics features an effective decoupling between the strong trapping axis and the weak trapping plane. The energy delivered during the kick is redistributed according to the symmetries of the system and satisfies the Virial theorem, allowing for the prediction of the final temperatures. We show that this behaviour is formally equivalent to the relaxation of massless relativistic Weyl fermions after a sudden displacement from the center of a harmonic trap.