Using Qubits to Measure Fidelity in Mesoscopic Systems

TL;DR

This paper proposes using flux or charge qubits to measure the fidelity of mesoscopic quantum systems, linking it to full counting statistics and deriving new theoretical insights.

Contribution

It introduces a novel approach to measure quantum fidelity in mesoscopic systems using qubits, connecting fidelity with full counting statistics.

Findings

Established the connection between fidelity and full counting statistics

Proposed a method to measure fidelity using flux or charge qubits

Derived new theoretical results on the generating function of full counting statistics

Abstract

We point out the similarities in the definition of the `fidelity' of a quantum system and the generating function determining the full counting statistics of charge transport through a quantum wire and suggest to use flux- or charge qubits for their measurement. As an application we use the notion of fidelity within a first-quantized formalism in order to derive new results and insights on the generating function of the full counting statistics.