Path-Degenerate Quantum Interferometry for Loss Resilience in Gravitational-Wave Detectors
Abstract
Optical decoherence degrades quantum correlations in squeezed states of light, severely limiting the quantum-nondemolition (QND) sensitivity of gravitational-wave detectors. Here, we propose the path-degenerate quantum interferometry scheme that obviates the need for entire optical subsystems---including additional filter cavities, auxiliary parametric amplifiers, and Faraday isolators---thereby drastically reducing spatial mode mismatches while inherently integrating variational output, a long-standing theoretical proposal to further deepen the QND regime. We experimentally demonstrate a core aspect of this scheme, achieving a shot-noise-preserving signal enhancement that directly counteracts the detrimental effects of readout loss. By delivering an improved signal-to-quantum-noise ratio solely through the consolidation and reduction of currently considered optical subsystems, our approach offers a highly optimized route toward enhanced quantum-noise reduction in upcoming LIGO upgrades and next-generation gravitational-wave observatories.
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BibTeX
@misc{rittmeyer2026pathdegenerate,
title = {{Path-Degenerate Quantum Interferometry for Loss Resilience in Gravitational-Wave Detectors}},
author = {Jonas Rittmeyer and Niels Boettner and Farid Khalili and Mikhail Korobko and Roman Schnabel},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.12204},
eprint = {2609.12204},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12204},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Path-Degenerate Quantum Interferometry for Loss Resilience in Gravitational-Wave Detectors
AU - Jonas Rittmeyer
AU - Niels Boettner
AU - Farid Khalili
AU - Mikhail Korobko
AU - Roman Schnabel
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2609.12204
UR - https://arxiv.org/abs/2609.12204
AB - Optical decoherence degrades quantum correlations in squeezed states of light, severely limiting the quantum-nondemolition (QND) sensitivity of gravitational-wave detectors. Here, we propose the path-degenerate quantum interferometry scheme that obviates the need for entire optical subsystems---including additional filter cavities, auxiliary parametric amplifiers, and Faraday isolators---thereby drastically reducing spatial mode mismatches while inherently integrating variational output, a long-standing theoretical proposal to further deepen the QND regime. We experimentally demonstrate a core aspect of this scheme, achieving a shot-noise-preserving signal enhancement that directly counteracts the detrimental effects of readout loss. By delivering an improved signal-to-quantum-noise ratio solely through the consolidation and reduction of currently considered optical subsystems, our approach offers a highly optimized route toward enhanced quantum-noise reduction in upcoming LIGO upgrades and next-generation gravitational-wave observatories.
ER -