Detector Readout of Analog Quantum Simulators

TL;DR

This paper investigates how to accurately measure many-body correlations in analog quantum simulators, demonstrating that proper coupling operators enable reliable readout despite backaction effects.

Contribution

It provides a theoretical framework for detector readout in quantum simulators, highlighting the importance of Wick's theorem for accurate correlation measurement.

Findings

Reliable correlation measurement is possible with Wick's theorem-compliant operators.

Backaction effects can be mitigated with appropriate coupling design.

Illustrated with harmonic oscillator and free electron gas simulators.

Abstract

An important step in quantum simulation is to measure the many-body correlations of the simulated model. For a practical quantum simulator composed of finite number of qubits and cavities, in contrast to ideal many-body systems in the thermodynamic limit, a measurement device can generate strong backaction on the simulator, which could prevent the accurate readout of the correlation functions. Here we calculate the readout of a detector coupled to an analog quantum simulator. We show that reliable characterization of the many-body correlations in the simulator can be achieved when the coupling operators obey the Wick's theorem. Our results are illustrated with two examples: a simulator for an harmonic oscillator and a simulator for the free electron gas.