Dynamical probing of high-order spin coherence in one-dimensional mixtures

TL;DR

This paper explores the out-of-equilibrium dynamics of one-dimensional ultracold fermions with strong interactions, revealing oscillating high-momentum tails driven by high-order spin coherence, with potential implications for quantum many-body physics.

Contribution

It extends previous analysis to out-of-equilibrium conditions, demonstrating the emergence and evolution of high-order spin coherence in a finite-sized system.

Findings

Oscillating high-momentum tails in momentum distribution.

High-order spin coherence governs the dynamics.

Maximum spin coherence occurs when spins are fully mixed.

Abstract

We investigate the dynamics of one-dimensional SU(2) ultracold fermions near the Tonks-Girardeau limit, confined in a box potential. The system is driven out of equilibrium by initially preparing the two spin components in a fully separated configuration, and its evolution is described by the Hamiltonian in the presence of strong repulsive interactions. Building on the results in [arXiv:2302.02828, Phys$.$Rev. A, 107, L061301 (2023)], we extend the analysis to out-of-equilibrium dynamics, uncovering the emergence of time-dependent oscillating high-momentum tails in the momentum distribution. These oscillations, due to the finite size of the system, are governed by a nonlocal, high-order spin coherence term, whose amplitude and phase evolve over time. We show that this term initially grows as time to the power N/2 and subsequently follows the spin-mixing dynamics of the system. Notably, when the spin components are fully mixed, the amplitude of this border-to-border spin coherence reaches its maximum value.