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Main Authors: Yang, Fan, Qi, Ran
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2501.08444
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author Yang, Fan
Qi, Ran
author_facet Yang, Fan
Qi, Ran
contents We systematically studied the dynamics of Fermi polarons driven by time-dependent scattering length using a time-dependent variational method. Starting from the non-interacting initial state, we calculated the evolution behavior of the contact, energy, and quasiparticle residue of this system as the scattering length $a_s(t)$ increases from zero. In the short-time evolution, we obtained analytical results, verifying that when $a_s(t)$ grows as $\sqrt{t}$, the contact $C(t)$ and energy $E(t)$ exhibit the maximum growth rate. Furthermore, we numerically solved the long-time evolution, when $a_s(t)$ is diven with a strength $β$ and a power $α$ as $a_s(t) = {\sqrt{2}β}/{k_F} {(ε_Ft)}^α$. For large driving strength, due to the interference between the polaron states and the non-interacting states, $C(t)$ and $Z(t)$ exhibit oscillatory behavior; For small $β$, the oscillatory behavior disappears due to the decay of the repulsive polaron into the continuum, and $C(t)$ and $Z(t)$ gradually relax to zero. The energy always saturates over long times for different driving strength. Additionally, our method is applicable to any time-dependent form of the scattering length.
format Preprint
id arxiv_https___arxiv_org_abs_2501_08444
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Non-equilibrium Dynamics of Fermi Polarons Driven by Time-dependent Interaction
Yang, Fan
Qi, Ran
Quantum Gases
We systematically studied the dynamics of Fermi polarons driven by time-dependent scattering length using a time-dependent variational method. Starting from the non-interacting initial state, we calculated the evolution behavior of the contact, energy, and quasiparticle residue of this system as the scattering length $a_s(t)$ increases from zero. In the short-time evolution, we obtained analytical results, verifying that when $a_s(t)$ grows as $\sqrt{t}$, the contact $C(t)$ and energy $E(t)$ exhibit the maximum growth rate. Furthermore, we numerically solved the long-time evolution, when $a_s(t)$ is diven with a strength $β$ and a power $α$ as $a_s(t) = {\sqrt{2}β}/{k_F} {(ε_Ft)}^α$. For large driving strength, due to the interference between the polaron states and the non-interacting states, $C(t)$ and $Z(t)$ exhibit oscillatory behavior; For small $β$, the oscillatory behavior disappears due to the decay of the repulsive polaron into the continuum, and $C(t)$ and $Z(t)$ gradually relax to zero. The energy always saturates over long times for different driving strength. Additionally, our method is applicable to any time-dependent form of the scattering length.
title Non-equilibrium Dynamics of Fermi Polarons Driven by Time-dependent Interaction
topic Quantum Gases
url https://arxiv.org/abs/2501.08444