activity
20222026
most citedAchieving the fundamental quantum limit of linear waveform estimation

12 citations · 43 across the 14 of their papers we have counts for

collaborators

14 papers

quant-ph2026

Global Precision Bounds and Success-Probability Guarantees in Quantum Parameter Learning

Federico Belliardo, James W. Gardner, Liang Jiang +1

Quantum metrology offers the possibility of quantum enhancements of the precision of various sensing tasks. In this manuscript, we tackle two open problems in the theory of single-…

astro-ph.IM2026

LIGO A: Detector Design and Science Prospects Beyond A+

L. Sun, K. Kuns, B. J. J. Slagmolen +1153

We present the LIGO A detector concept, an upgrade for the LIGO observatories based on room-temperature interferometers beyond the fifth observing run (O5). Building on th…

quant-ph2026

Gaussian Quantum Metrology with Realistic Linear Sensors

Jacques Ding, James W. Gardner, Tuvia Gefen +1

Quantum sensing promises enhanced precision, but the usual quantum Cramer Rao bound can be too optimistic for realistic linear sensors, where squeezing, filtering, and loss reshape…

quant-ph2026

Stochastic signal sensing with finite energy and dead time at the fundamental quantum limit

James W. Gardner, Tuvia Gefen, Matteo Fadel

State preparation, measurement, and reset operations take finite time and use finite energy in realistic experiments, yet the impact of this on optimal quantum metrological protoco…

quant-ph2026

Quantum superresolution and noise spectroscopy with quantum computing

James W. Gardner, Federico Belliardo, Gideon Lee +2

Quantum metrology of an incoherent signal is a canonical sensing problem related to superresolution and noise spectroscopy. We show that quantum computing can accelerate searches f…

quant-ph2025

Bayesian frequency estimation at the fundamental quantum limit

James W. Gardner, Tuvia Gefen, Ethan Payne +6

Searching for a weak signal at an unknown frequency is a canonical task in experiments probing fundamental physics such as gravitational-wave observatories and ultra-light dark mat…

quant-ph2025

Quantum Back Action Evasion with Reservoir Engineering

Yohei Nishino, James W. Gardner, Yanbei Chen +1

We propose a back-action evading scheme for a free mass that combines reservoir engineering with velocity measurement. The underlying principle follows the double-pass-type speed m…

quant-ph2025

Teleportation-based Speed Meter for Precision Measurement

Yohei Nishino, James W. Gardner, Yanbei Chen +1

We propose a quantum teleportation-based speed meter for interferometric displacement sensing. Two equivalent implementations are presented: an online approach that uses real-time…

quant-ph2025★ 1 cited

Lindblad estimation with fast and precise quantum control

James W. Gardner, Simon A. Haine, Joseph J. Hope +2

Enhancing precision sensors for stochastic signals using quantum techniques is a promising emerging field of physics. Estimating a weak stochastic waveform is the core task of many…

quant-ph2024★ 10 cited

Stochastic waveform estimation at the fundamental quantum limit

James W. Gardner, Tuvia Gefen, Simon A. Haine +4

Although measuring the deterministic waveform of a weak classical force is a well-studied problem, estimating a random waveform, such as the spectral density of a stochastic signal…

gr-qc2023★ 7 cited

Multi-messenger astronomy with a Southern-Hemisphere gravitational-wave observatory

James W. Gardner, Ling Sun, Ssohrab Borhanian +4

Joint observations of gravitational waves and electromagnetic counterparts will answer questions about cosmology, gamma-ray bursts, and the behaviour of matter at supranuclear dens…

gr-qc2023★ 12 cited

Achieving the fundamental quantum limit of linear waveform estimation

James W. Gardner, Tuvia Gefen, Simon A. Haine +2

Sensing a classical signal using a linear quantum device is a pervasive application of quantum-enhanced measurement. The fundamental precision limits of linear waveform estimation,…

quant-ph2022★ 10 cited

Nondegenerate internal squeezing: an all-optical, loss-resistant quantum technique for gravitational-wave detection

James W. Gardner, Min Jet Yap, Vaishali Adya +3

The detection of kilohertz-band gravitational waves promises discoveries in astrophysics, exotic matter, and cosmology. To improve the kilohertz quantum noise-limited sensitivity o…

gr-qc2022★ 3 cited

Continuous gravitational waves in the lab: recovering audio signals with a table-top optical microphone

James W. Gardner, Hannah Middleton, Changrong Liu +8

Gravitational-wave observatories around the world are searching for continuous waves: persistent signals from sources such as spinning neutron stars. These searches use sophisticat…