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Exploring kinetically induced bound states in triangular lattices with ultracold atoms: spectroscopic approach
by Ivan Morera Navarro, Christof Weitenberg, Klaus Sengstock, Eugene Demler
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Ivan Morera Navarro |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202402_00025v1 (pdf) |
| Date accepted: | 2024-02-28 |
| Date submitted: | 2024-02-16 11:04 |
| Submitted by: | Morera Navarro, Ivan |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
Quantum simulations with ultracold fermions in triangular optical lattices have recently emerged as a new platform for studying magnetism in frustrated systems. Experimental realizations of the Fermi Hubbard model revealed striking contrast between magnetism in bipartite and triangular lattices. In bipartite lattices magnetism is strongest at half filling, and doped charge carriers tend to suppress magnetic correlations. In triangular-type lattices for large $U/t$ and $t>0$, antiferromagnetism (ferromagnetism) gets enhanced by doping away from $n=1$ with holes (doublons) because kinetic energy of dopants can be lowered through developing magnetic correlations, corresponding to formation of magnetic polarons~\cite{Batista2017}. Snapshots of many-body states obtained with quantum gas microscopes~\cite{Greiner2022,Lebrat2023,Prichard2023} demonstrated existence of magnetic polarons by revealing the magnetic correlations around dopants at temperatures that considerably exceed superexchange energy scale. In this paper we discuss theoretically that additional insight into properties of magnetic polarons in triangular lattices can be achieved using spectroscopic experiments with ultracold atoms. We consider starting from a spin polarized state with small hole doping and applying a two-photon Raman photoexcitation, which transfers atoms into a different spin state. We show that such magnon injection spectra exhibit a separate peak corresponding to formation of a bound state between a hole and a magnon. This polaron peak is separated from the simple magnon spectrum by energy proportional to single particle tunneling and can be easily resolved with currently available experimental techniques. For some momentum transfer there is an additional peak corresponding to photoexciting a bound state between two holes and a magnon. We point out that in two component Bose mixtures in triangular lattices one can also create dynamical magnetic polarons, with one hole and one magnon forming a repulsive bound state.
Author comments upon resubmission
Below we provide a detailed list of changes to the manuscript and a response to the all criticisms
raised by the referees. Moreover, our response to the Referee’s also exhaustively covers their comments.
List of changes
We provide a list of the most important changes introduced in the manuscript. However, our response to the referees contains a detailed description of all changes made to the manuscript.
1. We have included a new section (Sec. 5.3) providing details on the calculation of the photoexcitation spectrum for the two-body problem and how to get the finite temperature photoexcitation spectrum.
2. We have improved the phrasing of the abstract and included a reference to the original theoretical work discussing antiferromagnetic polarons in the triangular lattice.
3. We have corrected typos in the manuscript and clarified notation in different equations.
4. We have included a discussion on kinetic frustration in Sec. 3.
5. We have incorporated new references on magnetic polarons in square lattices and Lanczos algorithm.
6. We have provided a discussion on the experimental feasibility of resolving the trimer peak.
Published as SciPost Phys. 16, 081 (2024)