Physics & Astronomy ETDs

Publication Date

Summer 7-28-2026

Abstract

Quantum metrology studies the use of quantum mechanical systems as measurement devices or sensors. Surprisingly, preparing a sensor in an entangled state can enhance measurement precision. The simplest protocols for entanglement enhancement sense only small changes in a quantity. The range of values over which a measurement protocol works is called its dynamic range. For many types of sensors we require end-to-end protocols that describe how to use entanglement to achieve enhanced precision over a large dynamic range. In this dissertation, we describe two approaches to achieving entanglement-enhanced sensing over a large dynamic range. The first approach uses entangling resources in a way that circumvents the dynamic-range limitation by numerically optimizing variational circuits. Our protocols show improved performance at fixed circuit depth compared to previous variational-circuit-based approaches, and the generality of our approach reveals several generic features of such protocols. The second approach uses adaptivity to first obtain a preliminary estimate of the quantity and then iteratively refines it. In particular, we describe the use of one-axis twisting dynamics at each stage of this protocol to minimize the expected estimation error.

Degree Name

Physics

Level of Degree

Doctoral

Department Name

Physics & Astronomy

First Committee Member (Chair)

Akimasa Miyake

Second Committee Member

Ivan H. Deutsch

Third Committee Member

Francisco Elohim Becerra

Fourth Committee Member

Tameem Albash

Project Sponsors

This work is supported by the National Science Foundation QLCI Q-SEnSE (Grant No. OMA- 2016244), and STAQ (Grants No. PHY-2325080).

Language

English

Keywords

Quantum metrology, Quantum sensing, Phase estimation, Variational quantum algorithms

Document Type

Dissertation

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