Work

Optimal Displacement Sensing with Spin-Dependent Squeezed States

Year: 2026

Type: article

Abstract: Displacement sensing is a fundamental task in metrology. However, the development of quantum-enhanced sensors that fully utilize the available degrees of freedom in many-body quantum systems remains an outstanding challenge. We propose many-body displacement sensing schemes that use spin-dependent squeezed (SDS) states—hybrid spin-boson states whose bosonic squeezed quadrature is conditioned on an auxiliary spin. We prove that SDS states are , i.e., their quantum Cramér-Rao bound saturates the Heisenberg limit. We propose explicit measurement sequences that can be readily implemented in systems such as trapped ions. We also introduce a scalable state-preparation protocol and numerically demonstrate the preparation of 8.7 dB of spin-dependent squeezing 15 times faster than the standard approach using second-order sidebands in trapped ions. The potential applications of our sensing protocols range from measuring single-photon scattering to searches for dark matter.

Source: PRX Quantum

DOI: 10.1103/mhvv-pr5d

Authors: Liam J. Bond, Christophe H. Valahu, Athreya Shankar, Ting Rei Tan, Arghavan Safavi-Naini

Institutions: QuSoft, University of Amsterdam, The University of Sydney, Indian Institute of Technology Madras

Language: English

Topic: Quantum Information and Cryptography

Subfield: Artificial Intelligence

Field: Computer Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,450