scholarly journals Quantum noise and vacuum fluctuations in balanced homodyne detections through ideal multi-mode detectors

2021 ◽  
Author(s):  
Kouji Nakamura
Keyword(s):  
Spectral Density ◽  
Gravitational Wave ◽  
Quantum Noise ◽  
Local Oscillator ◽  
Vacuum Fluctuations ◽  
Noise Spectral Density ◽  
Quantum Operator ◽  
Two Photon ◽  
Gravitational Wave Detectors ◽  
Readout Scheme

Abstract 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.

scholarly journals Light dark matter scattering in gravitational wave detectors

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Chun-Hao Lee ◽  
Chrisna Setyo Nugroho ◽  
Martin Spinrath
Keyword(s):  
Dark Matter ◽  
Gravitational Wave ◽  
Quantum Noise ◽  
Light Particle ◽  
Gravitational Wave Detectors ◽  
Particle Dark Matter ◽  
Potential Signal ◽  
Dark Matter Scattering

AbstractWe present prospects for discovering dark matter scattering in gravitational wave detectors. The focus of this work is on light, particle dark matter with masses below 1 $$\hbox {GeV}/\text {c}^{2}$$ GeV / c 2 . We investigate how a potential signal compares to typical backgrounds like thermal and quantum noise, first in a simple toy model and then using KAGRA as a realistic example. That shows that for a discovery much lighter and cooler mirrors would be needed. We also give some brief comments on space-based experiments and future atomic interferometers.

scholarly journals Optimization of quantum noise by completing the square of multiple interferometer outputs in quantum locking for gravitational wave detectors

2020 ◽  
Vol 384 (26) ◽  
pp. 126626
Author(s):  
Rika Yamada ◽  
Yutaro Enomoto ◽  
Atsushi Nishizawa ◽  
Koji Nagano ◽  
Sachiko Kuroyanagi ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Quantum Noise ◽  
Gravitational Wave Detectors

scholarly journals Reduction of quantum noise using the quantum locking with an optical spring for gravitational wave detectors

2021 ◽  
pp. 127365
Author(s):  
Rika Yamada ◽  
Yutaro Enomoto ◽  
Izumi Watanabe ◽  
Koji Nagano ◽  
Yuta Michimura ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Quantum Noise ◽  
Gravitational Wave Detectors

scholarly journals Consequences of Quantum Noise Control for the Relaxation Resonance Frequency and Phase Noise in Heterogeneous Silicon/III-V Lasers

2021 ◽  
Author(s):  
Dongwan Kim ◽  
Mark Harfouche ◽  
Huolei Wang ◽  
Christos T. Santis ◽  
Yaakov Vilenchik ◽  
...  
Keyword(s):  
Spectral Density ◽  
Resonance Frequency ◽  
Quantum Noise ◽  
Frequency Noise ◽  
Laser Mode ◽  
Noise Spectral Density ◽  
High Frequencies ◽  
Order Of Magnitude ◽  
Laser Design ◽  
Relaxation Resonance

Abstract We have recently introduced a new semiconductor laser design which is based on an extreme, 99%, reduction of the laser mode absorption losses. This was achieved by a laser mode design which confines the great majority of the modal energy (> 99%) in a low-loss Silicon guiding layer rather than in highly-doped, thus lossy, III-V p+ and n+ layers, which is the case with traditional III-V lasers. The resulting reduced electron-field interaction leads directly to a commensurate reduction of the spontaneous emission rate by the excited conduction band electrons into the laser mode and thus to a reduction of the frequency noise spectral density of the laser field often characterized by the Schawlow-Townes linewidth. In this paper, we demonstrate theoretically and present experimental evidence of yet another major beneficial consequence of the new laser design: a near total elimination of the contribution of amplitude-phase coupling (the Henry α parameter) to the frequency noise at “high” frequencies. This is due to an order of magnitude lowering of the relaxation resonance frequency of the laser. The practical elimination of this coupling enables yet another order of magnitude reduction of the frequency noise at high frequencies, resulting in a quantum-limited frequency noise spectral density of 130 Hz2/Hz (linewidth of 0.4 kHz) for frequencies beyond 680 MHz. This development is of key importance in the drive to semiconductor lasers with higher coherence, particularly in the context of integrated photonics with a small laser footprint.

QUANTUM SQUEEZING IN ADVANCED GRAVITATIONAL WAVE DETECTORS

2011 ◽  
Vol 20 (10) ◽  
pp. 2043-2049 ◽  
Author(s):  
SHEON CHUA ◽  
MICHAEL STEFSZKY ◽  
CONOR MMOW-LOWRY ◽  
BEN C. BUCHLER ◽  
KIRK MCKENZIE ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Second Generation ◽  
Quantum Noise ◽  
Squeezed States ◽  
Optical Components ◽  
Optical Techniques ◽  
Detection Range ◽  
Gravitational Wave Detectors ◽  
Quantum Optical

Second generation ground-based gravitational wave detectors, scheduled to be operating by the middle of this decade, will be limited in sensitivity over much of their detection range by optical quantum noise. As they will be operating at power levels close to the tolerance of the optical components, significant further improvement in sensitivity will require the use of quantum optical techniques such as the injection of squeezed states. In this paper we briefly review squeezing and plans for its implementation into advanced gravitational wave detectors.

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