Simulating generic spin-boson models with matrix product states

TL;DR

This paper introduces a versatile numerical method based on matrix product states for simulating the out-of-equilibrium dynamics of generic spin-boson models, capturing complex quantum correlations and decoherence effects.

Contribution

It provides a general, scalable framework for simulating spin-boson systems with arbitrary couplings and energy scales, including open-system dynamics and measurement statistics.

Findings

Accurately computes full counting statistics of collective spin measurements.

Quantifies infidelity due to spin-boson entanglement in quantum simulations.

Demonstrates incorporation of decoherence via quantum trajectories.

Abstract

The global coupling of few-level quantum systems ("spins") to a discrete set of bosonic modes is a key ingredient for many applications in quantum science, including large-scale entanglement generation, quantum simulation of the dynamics of long-range interacting spin models, and hybrid platforms for force and spin sensing. We present a general numerical framework for treating the out-of-equilibrium dynamics of such models based on matrix product states. Our approach applies for generic spin-boson systems: it treats any spatial and operator dependence of the two-body spin-boson coupling and places no restrictions on relative energy scales. We show that the full counting statistics of collective spin measurements and infidelity of quantum simulation due to spin-boson entanglement, both of which are difficult to obtain by other techniques, are readily calculable in our approach. We benchmark our method using a recently developed exact solution for a particular spin-boson coupling relevant to trapped ion quantum simulators. Finally, we show how decoherence can be incorporated within our framework using the method of quantum trajectories, and study the dynamics of an open-system spin-boson model with spatially non-uniform spin-boson coupling relevant for trapped atomic ion crystals in the presence of molecular ion impurities.