Speaker
Description
Since the first pioneering experiments on signatures of superconductivity in laser-field driven materials [1], dynamical condensation effects have attracted a lot of experimental and theoretical interest. We theoretically study a related effect, i.e. fermionic condensation, in the paradigmatic Fermi-Hubbard model. Starting from a completely uncorrelated initial state, we show that upon expansion of the system in one dimension, dynamical (quasi)condensation occurs not only for large interactions via the condensation of doublons [2,3], but also for small interactions [4]. We address the question of whether the dynamical (quasi)condensation effect persists in the thermodynamic limit and in higher dimensions. For this purpose, we use the time-dependent two-particle reduced density matrix method [5], which allows the extension to large system sizes, long propagation times, and two-dimensional (2D) systems. Our results indicate that the effect vanishes in the thermodynamic limit. However, especially in 2D, further investigation beyond numerically tractable system sizes calls for the use of ultracold atom quantum simulators, for which we show that the described effect can be investigated by probing density fluctuations.
[1] D. Fausti et al., Science 331, 189 (2011)
[2] M. Rigol et al., Phys. Rev. Lett. 93, 230404 (2004)
[3] L. Vidmar et al., Phys. Rev. X 7, 021012 (2017)
[4] I. Březinová et al., Phys. Rev. B 109, 174308 (2024)
[5] S. Donsa et al., Phys. Rev. Research 5, 033022 (2023)
