Continuous Measurement of Quantum Axion Dark Matter
Abstract
We provide a fully quantum-mechanical description of the continuous measurement of wavelike dark matter. Our focus is cavity haloscopes, although our results inform a broad range of axion searches. We extend the input-output formalism by treating the axion as a quantum field, finding how its quantum state is imprinted onto higher-order moments of observables of the outgoing transmission-line modes. We further develop a novel measurement-record formalism, which computes the joint probability distribution of all measurement outcomes and is well suited to studying the axion in the time domain. With it, we compute the exact axion-induced number distribution for the first time, demonstrating that it is not Poisson. We argue that virialized axion dark matter is expected to be in a Gaussian quantum state, and show that number or quadrature measurements can distinguish this from the predictions of a coherent state or even a Bose-Einstein condensate. Finally, we show that intrinsically quantum effects, such as those from Fock or squeezed axion states, are far too weak to detect.
Related
- Generalized Glauber theorem for dark-matter axion and graviton detection
- From Axion Detection to Dark Matter Astronomy
- Gravitational Instability of Cold Axion Dark Matter Beyond Minimal Coupling
- Squeezing and Decoherence of Axion Dark Matter
- Enhancing Constraints on Ultralight Axion Dark Matter from Gravitational Capture
BibTeX
@misc{bao2026continuous,
title = {{Continuous Measurement of Quantum Axion Dark Matter}},
author = {Yunjia Bao and Dhong Yeon Cheong and Nicholas L. Rodd and Joey Takach and Lian-Tao Wang and Kevin Zhou},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30250},
eprint = {2610.30250},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30250},
}
RIS
TY - UNPB
TI - Continuous Measurement of Quantum Axion Dark Matter
AU - Yunjia Bao
AU - Dhong Yeon Cheong
AU - Nicholas L. Rodd
AU - Joey Takach
AU - Lian-Tao Wang
AU - Kevin Zhou
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.30250
UR - https://arxiv.org/abs/2610.30250
AB - We provide a fully quantum-mechanical description of the continuous measurement of wavelike dark matter. Our focus is cavity haloscopes, although our results inform a broad range of axion searches. We extend the input-output formalism by treating the axion as a quantum field, finding how its quantum state is imprinted onto higher-order moments of observables of the outgoing transmission-line modes. We further develop a novel measurement-record formalism, which computes the joint probability distribution of all measurement outcomes and is well suited to studying the axion in the time domain. With it, we compute the exact axion-induced number distribution for the first time, demonstrating that it is not Poisson. We argue that virialized axion dark matter is expected to be in a Gaussian quantum state, and show that number or quadrature measurements can distinguish this from the predictions of a coherent state or even a Bose-Einstein condensate. Finally, we show that intrinsically quantum effects, such as those from Fock or squeezed axion states, are far too weak to detect.
ER -