Remote Quantum Sensing with Heisenberg Limited Sensitivity in Many Body Systems

TL;DR

This paper introduces a novel quantum sensing method using many-body system dynamics and projective measurements, achieving Heisenberg-limited sensitivity while enabling remote sensing and simplifying system initialization.

Contribution

It proposes a new quantum sensing approach that exploits residual information in many-body dynamics, surpassing standard limits and enabling remote, resource-efficient sensing.

Findings

Achieves Heisenberg-limited sensitivity with many-body dynamics.

Enables remote sensing, protecting the sample from invasive readout.

Simplifies initialization by avoiding complex entangled states.

Abstract

Quantum sensors have been shown to be superior to their classical counterparts in terms of resource efficiency. Such sensors have traditionally used the time evolution of special forms of initially entangled states, adaptive measurement basis change, or the ground state of many-body systems tuned to criticality. Here, we propose a different way of doing quantum sensing which exploits the dynamics of a many-body system, initialized in a product state, along with a sequence of projective measurements in a specific basis. The procedure has multiple practical advantages as it: (i) enables remote quantum sensing, protecting a sample from the potentially invasive readout apparatus; and (ii) simplifies initialization by avoiding complex entangled or critical ground states. From a fundamental perspective, it harnesses a resource so far unexploited for sensing, namely, the residual information from the unobserved part of the many-body system after the wave-function collapses accompanying the measurements. By increasing the number of measurement sequences, through the means of a Bayesian estimator, precision beyond the standard limit, approaching the Heisenberg bound, is shown to be achievable.