Quantum Sensing with Nanoelectronics: Fisher Information for an Applied Perturbation

TL;DR

This paper develops a theoretical framework for quantum sensing using nanoelectronic systems, deriving general expressions for quantum Fisher information in many-body systems, and demonstrating exponential scaling of sensitivity with system size.

Contribution

It introduces a general method to compute quantum Fisher information in nonequilibrium steady states of many-body systems, revealing how interactions can exponentially enhance sensing precision.

Findings

Quantum Fisher information can be expressed via susceptibilities and transport coefficients.

Electron interactions in quantum dots lead to exponential scaling of QFI with system size.

Current measurements in quantum circuits can exploit many-body effects for improved sensing.

Abstract

Quantum systems used for metrology can offer enhanced precision over their classical counterparts. The design of quantum sensors can be optimized by maximizing the quantum Fisher information (QFI), which characterizes the precision of parameter estimation for an ideal measurement. Here we consider the response of a quantum system as a means to estimate the strength of a weak external perturbation. General expressions for the QFI in the nonequilibrium steady-state are derived, which hold for arbitrary interacting many-body systems at finite or zero temperature, and can be related to susceptibilities or linear-response transport coefficients. For quantum dot nanoelectronics devices, we show that electron interactions can lead to *exponential* scaling of the QFI with system size, highlighting that quantum resources can be utilized in the full Fock space. The precision estimation of voltages and fields can also be achieved by practical measurements. In particular, we show that current-based metrology in quantum circuits can leverage many-body effects for enhanced sensing.