Spin dynamics of large-spin (spinor) fermions in a harmonic trap

TL;DR

This paper develops a Hartree-Fock theory to analyze collective spin oscillations in large-spin fermions within a harmonic trap, revealing persistent shoulders in oscillation periods that differ from previous resonance-based explanations.

Contribution

It introduces a novel Hartree-Fock approach to study collective dynamics in large-spin fermions, highlighting new behaviors in oscillation phases not previously understood.

Findings

Observation of a shoulder in oscillation period at small rotation angles

The system remains in a running phase, unlike previous resonance-based models

The shoulder persists in many-body oscillations, testable experimentally

Abstract

Understanding the collective dynamics in a many-body system has been a central task in condensed matter physics. To achieve this task, we develop a Hartree-Fock theory to study the collective oscillations of spinor Fermi system, motivated by recent experiment on spin-9/2 fermions. We observe an oscillation period shoulder for small rotation angles. Different from previous studies, where the shoulder is found connected to the resonance from periodic to running phase, here the system is always in a running phase in the two-body phase space. This shoulder survives even in the many-body oscillations, which could be tested in the experiments. We also show how these collective oscillations evolve from two- to many-body. Our theory provides an alternative way to understand the collective dynamics in large-spin Fermi systems.