Detecting Confined and Deconfined Spinons in Dynamical Quantum Simulations

TL;DR

This paper demonstrates how non-equilibrium dynamical spin-structure factors measured in quantum simulators can reveal fractional excitations like spinons and their confinement in quantum spin chains.

Contribution

It establishes a connection between many-body dynamics and quantum simulations, showing how nDSF can detect multi-spinon continua and spinon confinement in accessible quantum platforms.

Findings

nDSF can probe multi-spinon continua

Low-energy spinons can be confined into bound states

Quantum simulators can measure fractional excitations

Abstract

Dynamical spin-structure factor (DSF) contains fingerprint information of collective excitations in interacting quantum spin systems. In solid state experiments, DSF can be measured through neutron scatterings. However, it is in general challenging to compute the spectral properties accurately via many-body simulations. Currently, quantum simulation and computation constitute a thriving research field, which are believed to provide a very promising platform for simulating quantum many-body systems. In this work, we establish a link between the many-body dynamics and quantum simulations by studying the non-equilibrium DSF (nDSF) measured on direct product states, which are accessible in contemporary quantum simulators with Rydberg atoms, superconducting qubits, etc. Based on the many-body calculations of transverse field Ising chains, we find the nDSF can be used to sensitively probe the multi-spinon continua associated with the two-spinon creation and the spinon-antispinon process, etc. Moreover, we further demonstrate that the low-energy spinons can be confined -- forming spinon bound states -- under a finite longitudinal field. Our results pave the way of quantum simulation and manipulation of fractional excitations in highly-entangled quantum many-body systems.