Ferromagnetism in tilted fermionic Mott insulators

Fuente: arXiv
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Main Authors: Takasan, Kazuaki, Tezuka, Masaki
Format: Preprint
Published: 2021
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_version_ 1866909922969518080
author Takasan, Kazuaki
Tezuka, Masaki
author_facet Takasan, Kazuaki
Tezuka, Masaki
contents We investigate the magnetism in tilted fermionic Mott insulators. With a small tilt, the fermions are still localized and form a Mott-insulating state, where the localized spins interact via antiferromagnetic exchange coupling. While the localized state is naively expected to be broken with a large tilt, in fact, the fermions are still localized under a large tilt due to the Wannier-Stark localization and it can be regarded as a localized spin system. We find that the sign of the exchange coupling is changed and the ferromagnetic interaction is realized under the large tilt. To show this, we employ perturbation theory and real-time numerical simulation of the fermionic Hubbard chain. Our simulation exhibits that it is possible to effectively control the speed and time direction of the dynamics by changing the size of the tilt, which may be useful for experimentally measuring out-of-time-ordered correlators. Finally, we discuss experimental platforms, such as ultracold atoms in an optical lattice, to observe these phenomena.
format Preprint
id arxiv_https___arxiv_org_abs_2111_03857
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Ferromagnetism in tilted fermionic Mott insulators
Takasan, Kazuaki
Tezuka, Masaki
Quantum Gases
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
We investigate the magnetism in tilted fermionic Mott insulators. With a small tilt, the fermions are still localized and form a Mott-insulating state, where the localized spins interact via antiferromagnetic exchange coupling. While the localized state is naively expected to be broken with a large tilt, in fact, the fermions are still localized under a large tilt due to the Wannier-Stark localization and it can be regarded as a localized spin system. We find that the sign of the exchange coupling is changed and the ferromagnetic interaction is realized under the large tilt. To show this, we employ perturbation theory and real-time numerical simulation of the fermionic Hubbard chain. Our simulation exhibits that it is possible to effectively control the speed and time direction of the dynamics by changing the size of the tilt, which may be useful for experimentally measuring out-of-time-ordered correlators. Finally, we discuss experimental platforms, such as ultracold atoms in an optical lattice, to observe these phenomena.
title Ferromagnetism in tilted fermionic Mott insulators
topic Quantum Gases
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2111.03857