Phase estimation as a quantum nondemolition measurement

TL;DR

This paper demonstrates that the phase estimation algorithm can be interpreted as a quantum nondemolition measurement, providing new insights into its operation in both discrete and continuous variable quantum systems.

Contribution

It establishes a novel perspective by linking phase estimation with quantum nondemolition measurement techniques, enhancing understanding of quantum measurement processes.

Findings

Phase estimation can be viewed as a quantum nondemolition measurement.

The interpretation applies to both discrete and continuous variable systems.

This perspective may improve quantum measurement strategies.

Abstract

The phase estimation algorithm, which is at the heart of a variety of quantum algorithms, including Shor's factoring algorithm, allows a quantum computer to accurately determine an eigenvalue of an unitary operator. Quantum nondemolition measurements are a quantum mechanical procedure, used to overcome the standard quantum limit when measuring an observable. We show that the phase estimation algorithm, in both the discrete and continuous variable setting, can be viewed as a quantum nondemolition measurement.