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Authors = Yuta Michimura

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16 pages, 3064 KiB  
Article
TOrsion-Bar Antenna: A Ground-Based Detector for Low-Frequency Gravity Gradient Measurement
by Satoru Takano, Tomofumi Shimoda, Yuka Oshima, Ching Pin Ooi, Perry William Fox Forsyth, Mengdi Cao, Kentaro Komori, Yuta Michimura, Ryosuke Sugimoto, Nobuki Kame, Shingo Watada, Takaaki Yokozawa, Shinji Miyoki, Tatsuki Washimi and Masaki Ando
Galaxies 2024, 12(6), 78; https://doi.org/10.3390/galaxies12060078 - 20 Nov 2024
Viewed by 1958
Abstract
The Torsion-Bar Antenna (TOBA) is a torsion pendulum-based gravitational detector developed to observe gravitational waves in frequencies between 1 mHz and 10 Hz. The low resonant frequency of the torsion pendulum enables observation in this frequency band on the ground. The final target [...] Read more.
The Torsion-Bar Antenna (TOBA) is a torsion pendulum-based gravitational detector developed to observe gravitational waves in frequencies between 1 mHz and 10 Hz. The low resonant frequency of the torsion pendulum enables observation in this frequency band on the ground. The final target of TOBA is to observe gravitational waves with a 10 m detector and expand the observation band of gravitational waves. In this paper, an overview of TOBA, including the previous prototype experiments and the current ongoing development, is presented. Full article
(This article belongs to the Special Issue Challenges for Third-Generation Gravitational Wave Detectors and Beyond)
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13 pages, 1673 KiB  
Article
Optimization of Quantum Noise in Space Gravitational-Wave Antenna DECIGO with Optical-Spring Quantum Locking Considering Mixture of Vacuum Fluctuations in Homodyne Detection
by Kenji Tsuji, Tomohiro Ishikawa, Kentaro Komori, Koji Nagano, Yutaro Enomoto, Yuta Michimura, Kurumi Umemura, Ryuma Shimizu, Bin Wu, Shoki Iwaguchi, Yuki Kawasaki, Akira Furusawa and Seiji Kawamura
Galaxies 2023, 11(6), 111; https://doi.org/10.3390/galaxies11060111 - 9 Nov 2023
Cited by 2 | Viewed by 2126
Abstract
Quantum locking using optical spring and homodyne detection has been devised to reduce the quantum noise that limits the sensitivity of the DECIGO, a space-based gravitational-wave antenna in the frequency band around 0.1 Hz for the detection of primordial gravitational waves. The reduction [...] Read more.
Quantum locking using optical spring and homodyne detection has been devised to reduce the quantum noise that limits the sensitivity of the DECIGO, a space-based gravitational-wave antenna in the frequency band around 0.1 Hz for the detection of primordial gravitational waves. The reduction in the upper limit of energy density ΩGW from 2×10−15 to 1×10−16, as inferred from recent observations, necessitates improved sensitivity in the 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. Full article
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26 pages, 5912 KiB  
Article
The Current Status and Future Prospects of KAGRA, the Large-Scale Cryogenic Gravitational Wave Telescope Built in the Kamioka Underground
by Homare Abe, Tomotada Akutsu, Masaki Ando, Akito Araya, Naoki Aritomi, Hideki Asada, Yoichi Aso, Sangwook Bae, Rishabh Bajpai, Kipp Cannon, Zhoujian Cao, Eleonora Capocasa, Man Leong Chan, Dan Chen, Yi-Ru Chen, Marc Eisenmann, Raffaele Flaminio, Heather K. Fong, Yuta Fujikawa, Yuya Fujimoto, I. Putu Wira Hadiputrawan, Sadakazu Haino, Wenbiao Han, Kazuhiro Hayama, Yoshiaki Himemoto, Naoatsu Hirata, Chiaki Hirose, Tsung-Chieh Ho, Bin-Hua Hsieh, He-Feng Hsieh, Chia-Hsuan Hsiung, Hsiang-Yu Huang, Panwei Huang, Yao-Chin Huang, Yun-Jing Huang, David C. Y. Hui, Kohei Inayoshi, Yuki Inoue, Yousuke Itoh, Pil-Jong Jung, Takaaki Kajita, Masahiro Kamiizumi, Nobuyuki Kanda, Takashi Kato, Chunglee Kim, Jaewan Kim, Young-Min Kim, Yuichiro Kobayashi, Kazunori Kohri, Keiko Kokeyama, Albert K. H. Kong, Naoki Koyama, Chihiro Kozakai, Jun’ya Kume, Sachiko Kuroyanagi, Kyujin Kwak, Eunsub Lee, Hyung Won Lee, Ray-Kuang Lee, Matteo Leonardi, Kwan-Lok Li, Pengbo Li, Lupin Chun-Che Lin, Chun-Yu Lin, En-Tzu Lin, Hong-Lin Lin, Guo-Chin Liu, Ling-Wei Luo, Miftahul Ma’arif, Yuta Michimura, Norikatsu Mio, Osamu Miyakawa, Kouseki Miyo, Shinji Miyoki, Nozomi Morisue, Kouji Nakamura, Hiroyuki Nakano, Masayuki Nakano, Tatsuya Narikawa, Lan Nguyen Quynh, Takumi Nishimoto, Atsushi Nishizawa, Yoshihisa Obayashi, Kwangmin Oh, Masatake Ohashi, Tomoya Ohashi, Masashi Ohkawa, Yoshihiro Okutani, Ken-ichi Oohara, Shoichi Oshino, Kuo-Chuan Pan, Alessandro Parisi, June Gyu Park, Fabián E. Peña Arellano, Surojit Saha, Kazuki Sakai, Takahiro Sawada, Yuichiro Sekiguchi, Lijing Shao, Yutaka Shikano, Hirotaka Shimizu, Katsuhiko Shimode, Hisaaki Shinkai, Ayaka Shoda, Kentaro Somiya, Inhyeok Song, Ryosuke Sugimoto, Jishnu Suresh, Takamasa Suzuki, Takanori Suzuki, Toshikazu Suzuki, Hideyuki Tagoshi, Hirotaka Takahashi, Ryutaro Takahashi, Hiroki Takeda, Mei Takeda, Atsushi Taruya, Takayuki Tomaru, Tomonobu Tomura, Lucia Trozzo, Terrence T. L. Tsang, Satoshi Tsuchida, Takuya Tsutsui, Darkhan Tuyenbayev, Nami Uchikata, Takashi Uchiyama, Tomoyuki Uehara, Koh Ueno, Takafumi Ushiba, Maurice H. P. M. van Putten, Tatsuki Washimi, Chien-Ming Wu, Hsun-Chung Wu, Tomohiro Yamada, Kazuhiro Yamamoto, Takahiro Yamamoto, Ryo Yamazaki, Shu-Wei Yeh, Jun’ichi Yokoyama, Takaaki Yokozawa, Hirotaka Yuzurihara, Simon Zeidler and Yuhang Zhaoadd Show full author list remove Hide full author list
Galaxies 2022, 10(3), 63; https://doi.org/10.3390/galaxies10030063 - 26 Apr 2022
Cited by 26 | Viewed by 8648
Abstract
KAGRA is a gravitational-wave (GW) detector constructed in Japan with two unique key features: It was constructed underground, and the test-mass mirrors are cooled to cryogenic temperatures. These features are not included in other kilometer-scale detectors but will be adopted in future detectors [...] Read more.
KAGRA is a gravitational-wave (GW) detector constructed in Japan with two unique key features: It was constructed underground, and the test-mass mirrors are cooled to cryogenic temperatures. These features are not included in other kilometer-scale detectors but will be adopted in future detectors such as the Einstein Telescope. KAGRA performed its first joint observation run with GEO600 in 2020. In this observation, the sensitivity of KAGRA to GWs was inferior to that of other kilometer-scale detectors such as LIGO and Virgo. However, further upgrades to the detector are ongoing to reach the sensitivity for detecting GWs in the next observation run, which is scheduled for 2022. In this article, the current situation, sensitivity, and future perspectives are reviewed. Full article
(This article belongs to the Special Issue Present and Future of Gravitational Wave Astronomy)
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15 pages, 2020 KiB  
Article
Improvement of the Target Sensitivity in DECIGO by Optimizing Its Parameters for Quantum Noise Including the Effect of Diffraction Loss
by Tomohiro Ishikawa, Shoki Iwaguchi, Yuta Michimura, Masaki Ando, Rika Yamada, Izumi Watanabe, Koji Nagano, Tomotada Akutsu, Kentaro Komori, Mitsuru Musha, Takeo Naito, Taigen Morimoto and Seiji Kawamura
Galaxies 2021, 9(1), 14; https://doi.org/10.3390/galaxies9010014 - 16 Feb 2021
Cited by 18 | Viewed by 3422
Abstract
The DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is the future Japanese, outer space gravitational wave detector. 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 [...] Read more.
The DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO) is the future Japanese, outer space gravitational wave detector. 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 toward 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) of 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 dimensions and implementing other noise sources. Full article
(This article belongs to the Special Issue Gravitational Wave Detectors)
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14 pages, 728 KiB  
Article
Quantum Noise in a Fabry-Perot Interferometer Including the Influence of Diffraction Loss of Light
by Shoki Iwaguchi, Tomohiro Ishikawa, Masaki Ando, Yuta Michimura, Kentaro Komori, Koji Nagano, Tomotada Akutsu, Mitsuru Musha, Rika Yamada, Izumi Watanabe, Takeo Naito, Taigen Morimoto and Seiji Kawamura
Galaxies 2021, 9(1), 9; https://doi.org/10.3390/galaxies9010009 - 26 Jan 2021
Cited by 12 | Viewed by 3250
Abstract
The DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is designed to detect gravitational waves at frequencies between 0.1 and 10 Hz. In this frequency band, one of the most important science targets is the detection of primordial gravitational waves. DECIGO plans to use a [...] Read more.
The DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is designed to detect gravitational waves at frequencies between 0.1 and 10 Hz. In this frequency band, one of the most important science targets is the detection of primordial gravitational waves. DECIGO plans to use a space interferometer with optical cavities to increase its sensitivity. For evaluating its sensitivity, diffraction of the laser light has to be adequately considered. There are two kinds of diffraction loss: leakage loss outside the mirror and higher-order mode loss. These effects are treated differently inside and outside of the Fabry-Perot (FP) cavity. We estimated them under the conditions that the FP cavity has a relatively high finesse and the higher-order modes do not resonate. As a result, we found that the effects can be represented as a reduction of the effective finesse of the cavity with regard to quantum noise. This result is useful for optimization of the design of DECIGO. This method is also applicable to any FP cavities with a relatively small beam cut and the finesse sufficiently higher than 1. Full article
(This article belongs to the Special Issue Gravitational Wave Detectors)
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