Palestrante: Willian Massashi Hisano Natori

                   (DFMC - IFGW - Unicamp)

Abstract:

Frustrated magnetism is a fertile field to discover, propose, and characterize new phases of matter. Much of the research in this topic has been focused on the realization of a quantum spin liquid (QSL), a macroscopic singlet state characterized by fractionalized excitations. We will focus 

on QSL candidates simulated by ultracold Rydberg atoms placed on the ruby lattice [1]. Such simulations are modeled by a classical spin-3/2 honeycomb model that hosts different QSLs depending on the applied transverse field, including the kagome RVB and the Kitaev spin liquid 

(KSL) [2]. In this seminar, I will present a recent study [3] in which we unveiled the exact partition function and static structure factor of the classical model. The nonvanishing zero-point entropy and the spin disorder of the phase can be interpreted in terms of a kagome spin ice. 

We were also able to introduce a perturbation inducing immobile excitations akin to fractons, which can be combined into other excitations with restricted mobility. Building upon the geometrical flexibility of quantum simulators, I suggest that they can pave a way to implement  KSLs on fractal lattices. I will show preliminary results on the ground state of the Kitaev model on a specific fractal, which hosts several modes localized on specific edges of the fractal.  At high temperatures, I also show how the diffusion of Majorana fermions is restricted when it occurs in this geometry as opposed to the behavior in two-dimensional lattices. Venues for future research will be presented by the end of the talk. 

[1] Semeghini et al., Science 374, 1242–1247 (2021)

[2] R. Verresen and A. Vishwanath, Phys. Rev. X,12,.041029 (2022)

[3] W. Fontana, F. Oliviero, R. Pereira, W. Natori, arXiv 2501.16898