Quantum noise and vacuum fluctuations in balanced homodyne detections through ideal multi-mode detectors
| Autor: | Kouji Nakamura |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Physics
Quantum Physics Photon Noise spectral density Local oscillator Operator (physics) Quantum noise General Physics and Astronomy FOS: Physical sciences Expectation value General Relativity and Quantum Cosmology (gr-qc) General Relativity and Quantum Cosmology Computational physics Homodyne detection Quantum Physics (quant-ph) Astrophysics - Instrumentation and Methods for Astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) Quantum fluctuation |
| Popis: | The balanced homodyne detection as a readout scheme of gravitational-wave detectors is carefully examined from the quantum field theoretical point of view. The readout scheme in gravitational-wave detectors specifies the directly measured quantum operator in the detection. This specification is necessary when we apply the recently developed quantum measurement theory to gravitational-wave detections. We examine the two models of measurement. One is the model in which the directly measured quantum operator at the photodetector is Glauber's photon number operator, and the other is the model in which the power operator of the optical field is directly measured. These two are regarded as ideal models of photodetectors. We first show these two models yield the same expectation value of the measurement. Since it is consensus in the gravitational-wave community that vacuum fluctuations contribute to the noises in the detectors, we also clarify the contributions of vacuum fluctuations to the quantum noise spectral density without using the two-photon formulation which is used in the gravitational-wave community. We found that the conventional noise spectral density in the two-photon formulation includes vacuum fluctuations from the main interferometer but does not include those from the local oscillator. Although the contribution of vacuum fluctuations from the local oscillator theoretically yields the difference between the above two models in the noise spectral densities, this difference is negligible in realistic situations. 39 pages, 5 figures, This is the full paper version of [arXiv:2101.11838 [gr-qc]] (v1); Acknowledgements is added (v2); Minor changes in Sec.1, Sec.6, Fig.3, and Fig.A2. Some typos are corrected (v3) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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