Abstract
We propose a scheme to implement Kitaev’s honeycomb model with cold atoms, based on a periodic (Floquet) drive, in view of realizing and probing non-Abelian chiral spin liquids using quantum simulators. We derive the effective Hamiltonian to leading order in the inverse-frequency expansion, and show that the drive opens up a topological gap in the spectrum without mixing the effective Majorana and vortex degrees of freedom. We address the challenge of probing the physics of Majorana fermions, while having access only to the original composite spin degrees of freedom. Specifically, we propose to detect the properties of the chiral spin liquid phase using gap spectroscopy and edge quenches in the presence of the Floquet drive. The resulting chiral edge signal, which relates to the thermal Hall effect associated with neutral Majorana currents, is found to be robust for realistically prepared states. By combining strong interactions with Floquet engineering, our work paves the way for future studies of non-Abelian excitations and quantized thermal transport using quantum simulators.
9 More- Received 2 December 2022
- Accepted 13 April 2023
DOI:https://doi.org/10.1103/PRXQuantum.4.020329
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Chiral spin liquids are one of the most intriguing quantum phases of matter. Predicted to exist in two-dimensional quantum systems, these topological phases exhibit excitations known as non-Abelian anyons, which go beyond the conventional boson and fermion paradigm. Despite intense efforts in condensed-matter physics, it is still debated whether quantum spin liquid order actually exists in nature. One emblematic instance is the so-called Kitaev honeycomb model, which admits an exact analytical solution. Remarkably, recent advances in the design of quantum simulators open a possible path for the first experimental realization of the original Kitaev honeycomb model, hence suggesting that chiral spin liquids (including their exotic excitations) can be studied and manipulated in a highly controlled experimental environment.
In this work, we propose a realization of the Kitaev honeycomb model using quantum simulators based on nonequilibrium periodic drives. The model exhibits a chiral spin liquid ground state, which features non-Abelian excitations consisting of vortex (flux) and Majorana fractional excitations. We introduce practical methods for probing the topological properties of this exotic state of matter, using well-designed drive sequences and available measurement schemes. In particular, our detection protocols allow us to unambiguously reveal the topological heat current associated with Majorana edge modes, a hallmark signature of chiral spin liquids.
This work paves the way for the quantum simulation of chiral spin liquids, offering an appealing alternative to their experimental investigation in quantum materials.