129 research outputs found
Axion Dark Matter Search with Interferometric Gravitational Wave Detectors
Axion dark matter differentiates the phase velocities of the
circular-polarized photons. In this Letter, a scheme to measure the phase
difference by using a linear optical cavity is proposed. If the scheme is
applied to the Fabry-P\'erot arm of Advanced LIGO-like (Cosmic-Explorer-like)
gravitational wave detector, the potential sensitivity to the axion-photon
coupling constant, , reaches GeV GeV at the axion mass
eV ( eV) and remains at around
this sensitivity for 3 orders of magnitude in mass. Furthermore, its
sensitivity has a sharp peak reaching
GeV GeV at eV
( eV). This sensitivity can be achieved without loosing
any sensitivity to gravitational waves.Comment: 7 pages, 2 figure
Axion dark matter search using arm cavity transmitted beams of gravitational wave detectors
Axion is a promising candidate for ultralight dark matter which may cause a
polarization rotation of laser light. Recently, a new idea of probing the axion
dark matter by optical linear cavities used in the arms of gravitational wave
detectors has been proposed [Phys. Rev. Lett. 123, 111301 (2019)]. In this
article, a realistic scheme of the axion dark matter search with the arm cavity
transmission ports is revisited. Since photons detected by the transmission
ports travel in the cavity for odd-number of times, the effect of axion dark
matter on their phases is not cancelled out and the sensitivity at low-mass
range is significantly improved compared to the search using reflection ports.
We also take into account the stochastic nature of the axion field and the
availability of the two detection ports in the gravitational wave detectors.
The sensitivity to the axion-photon coupling, , of the
ground-based gravitational wave detector, such as Advanced LIGO, with 1-year
observation is estimated to be GeV
below the axion mass of eV, which improves upon the limit achieved
by the CERN Axion Solar Telescope.Comment: 10 pages, 4 figure
First Results of Axion Dark Matter Search with DANCE
Axions are one of the well-motivated candidates for dark matter, originally
proposed to solve the strong CP problem in particle physics. Dark matter Axion
search with riNg Cavity Experiment (DANCE) is a new experimental project to
broadly search for axion dark matter in the mass range of . We aim to detect the rotational oscillation of
linearly polarized light caused by the axion-photon coupling with a bow-tie
cavity. The first results of the prototype experiment, DANCE Act-1, are
reported from a 24-hour observation. We found no evidence for axions and set
95% confidence level upper limit on the axion-photon coupling in . Although the bound did not exceed the current best
limits, this optical cavity experiment is the first demonstration of
polarization-based axion dark matter search without any external magnetic
field.Comment: 9 pages, 8 figure
Use of Balloon Enteroscopy in Preoperative Diagnosis of Neurofibromatosis-Associated Gastrointestinal Stromal Tumours of the Small Bowel: A Case Report
Neurofibromatosis type I (NF1) is one of the most common inheritable disorders and is associated with an increased risk of gastrointestinal stromal tumours (GISTs). However, the predominant location of these lesions in the small bowel makes them difficult to diagnose. We report the successful use of balloon enteroscopy in conjunction with conventional methods for clinical diagnosis of jejunal GISTs in a 70-year-old man with NF1 who presented with melaena. The importance of screening NF1 patients for GISTs and the complementary role of balloon enteroscopy with capsule endoscopy in such diagnoses is discussed
Optimization of quantum noise in space gravitational-wave antenna DECIGO with optical-spring quantum locking considering mixture of vacuum fluctuations in homodyne detection
Quantum locking using optical spring and homodyne detection has been devised
to reduce quantum noise that limits the sensitivity of DECIGO, a space-based
gravitational wave antenna in the frequency band around 0.1 Hz for detection of
primordial gravitational waves. The reduction in the upper limit of energy
density from to
, as inferred from recent observations, necessitates
improved sensitivity in DECIGO to meet its primary science goals. To accurately
evaluate the effectiveness of this method, this paper considers a detection
mechanism that takes into account the influence of vacuum fluctuations on
homodyne detection. In addition, an advanced signal processing method is
devised to efficiently utilize signals from each photodetector, and design
parameters for this configuration are optimized for the quantum noise. Our
results show that this method is effective in reducing quantum noise, despite
the detrimental impact of vacuum fluctuations on its sensitivity.Comment: 12 pages, 5 figure
Improvement of the target sensitivity in DECIGO by optimizing its parameters for quantum noise including the effect of diffraction loss
DECIGO is the future Japanese gravitational wave detector in outer space. We
previously set the default design parameters to provide a good target
sensitivity to detect the primordial gravitational waves (GWs). However, the
updated upper limit of the primordial GWs by the Planck observations motivated
us for further optimization of the target sensitivity. Previously, we had not
considered optical diffraction loss due to the very long cavity length. In this
paper, we optimize various DECIGO parameters by maximizing the signal-to-noise
ratio (SNR), for the primordial GWs to quantum noise including the effects of
diffraction loss. We evaluated the power spectrum density for one cluster in
DECIGO utilizing the quantum noise of one differential Fabry-Perot
interferometer. Then we calculated the SNR by correlating two clusters in the
same position. We performed the optimization for two cases: the constant
mirror-thickness case and the constant mirror-mass case. As a result, we
obtained the SNR dependence on the mirror radius, which also determines various
DECIGO parameters. This result is the first step toward optimizing the DECIGO
design by considering the practical constraints on the mirror dimension and
implementing other noise sources.Comment: 13 pages, 12 figure
First-step experiment in developing optical-spring quantum locking for DECIGO: sensitivity optimization for simulated quantum noise by completing the square
DECi-hertz Interferometer Gravitational Wave Observatory (DECIGO) is a future
mission for a space-borne laser interferometer. DECIGO has 1,000-km-long arm
cavities mainly to detect the primordial gravitational waves (PGW) at lower
frequencies around 0.1 Hz. Observations in the electromagnetic spectrum have
lowered the bounds on the upper limit of PGW energy density (). As a result, DECIGO's target sensitivity, which
is mainly limited by quantum noise, needs further improvement. To maximize the
feasibility of detection while constrained by DECIGO's large diffraction loss,
a quantum locking technique with an optical spring was theoretically proposed
to improve the signal-to-noise ratio of the PGW. In this paper, we
experimentally verify one key element of the optical-spring quantum locking:
sensitivity optimization by completing the square of multiple detector outputs.
This experiment is operated on a simplified tabletop optical setup with
classical noise simulating quantum noise. We succeed in getting the best of the
sensitivities with two different laser powers by the square completion method.Comment: 10 pages, 14 figure
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