News

2023-10-28 (Papers)
- We demonstrated an ehancement of an optical spring using a non-linear optical effect for the first time. The optical spring used for the signal amplification in wade range of applications, including gravitational wave detectors and experiments to probe quantum of nature of mechanical oscillators. Our technique can be applied to improve various optical precision measurements. The joint paper was selected as Editors' Suggestion in Physical Review Letters. The paper was also featured in Physics Magazine, and was press released. Phys. Rev. Lett. 132, 143602 (2024) Physics 17, s40 (2024)
2024-04-01 (Papers)
- The article for the general public summarizing the result of the gauge boson dark matter search using KAGRA data from 2020 was released in the LIGO-Virgo-KAGRA website. The article was written by myself, and is titled "A new dark matter search with the sapphire mirrors of KAGRA gravitational-wave detector."
2024-04-01 (CV)
- I moved to the University of Tokyo as an Associate Professor at Research Center for the Early Universe. I was selected as a FY2023 The University of Tokyo Excellent Young Researcher.
2024-03-05 (Papers)
- We have placed upper limits to gauge boson dark matter using KAGRA data from 2020. By measuring the distance between KAGRA's sapphire mirrors and fused silica mirrors, gauge boson dark matter can be searched with better sensitivity than LIGO and Virgo, once the designed sensitivity is achieved. Our study has demonstrated the feasibility of using auxiliary length channels of gravitational-wave detectors like KAGRA for astrophysical observations. I have chaired the paper writing team, and Jun'ya Kume wrote the most part of this LIGO-Virgo-KAGRA collaboration paer authored by 1800 researchers. The paper was posted on arXiv.arXiv:2403.03004
2024-02-28 (Papers)
- We have estabilished a method to characterize birefringence inhomogeneity of large mirrors used for KAGRA and future gravitational wave detectors. To show the effectiveness of our method, we have reconstructed birefringence maps for KAGRA sapphire mirrors, and confirmed that in-situ birefringence measurements using KAGRA interferometer matches well with our expectation. arXiv:2402.18006
2024-01-29 (Papers)
- We have formulated the noise coupling mechanism from birefringence fluctuations of mirrors used for laser interferometric gravitational wave detectors. Mirrors made from crystalline materials are considered to be promising for reducing thermal noises in future detectors. We have pointed out that not only the static birefringence of the crystal, but also its fluctuations need to be small enough to realize the future projects, and summarized the requirements. The first author paper was selected as Editors' Suggestion in Physical Review D. Phys. Rev. D 109, 022009 (2024)
2023-12-16 (JapaneseConferences)
- I gave a report for the experiment to search for axion dark matter with an optical ring cavity at the final research evaluation meeting of PRESTO "Innovative optics and photonics" at JST Tokyo Headquarters Annex. Slides are here.
2023-12-01 (InternationalConferences)
- I gave an invited talk on the DANCE project to search for axion dark matter with an optical ring cavity at International workshop on "Double Beta Decay and Underground Science" held at Hilton Waikoloa Village. My presentation was in a joint session with the 2023 Fall Meeting of the Division of Nuclear Physics of the American Physical Society and Physical Society of Japan. Slides are here.
2023-11-27 (Papers)
- We have formulated a method to correctly take into account the stochastic effects on observation of ultralight dark matter. Our formulation can be used for arbitrary measurement time, and is a generic method which can be applied to both scalar fields like axions and vector fields like dark photons with velocity-dependent signals. The joint paper was published in Physical Review D. Phys. Rev. D 108, 092010 (2023)
2023-11-26 (InternationalConferences)
- I gave an invited talk on the status of KAGRA and its key roles in multi-messenger astronomy at Joint RIKEN/N3AS Workshop on Multi-Messenger Astrophysics held at Hilton Waikoloa Village. The workshop was held within the 2023 Fall Meeting of the Division of Nuclear Physics of the American Physical Society and Physical Society of Japan. Slides are here (login required).
2023-11-14 (InternationalConferences)
- I gave a talk on our idea to exponentially enhance the amount of gravity-induced quantum entanglement using unstable optically-levitated mirrors at the 5th QFilter Workshop held at Okinawa Institute of Science and Technology. Slides are here.
2023-11-11 (JapaneseConferences)
- I gave a talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics" at Lake Biwa. Slides are here.
2023-10-10 (Papers)
- Our paper reporting the first results from DANCE to search for axion dark matter using an optical ring cavity was published in Physical Review D. This is the first demonstration of polarization-based axion dark matter search with an optical cavity under no magnetic field. Phys. Rev. D 108, 072005 (2023)
2023-09-22 (Documents)
- A science magazine "Kagaku" from Iwanami Shoten features dark matter in October 2023 issue. The articles in this issue were written by researchers in the Transformative Research Areas (A) "What is dark matter? - Comprehensive study of the huge discovery space in dark matter." I wrote an article "Laser interferometer searches for dark matter waves."
2023-09-20 (Documents)
- I wrote an article "Restart of the Joint Observing Run by the Global Gravitational Wave Detector Network and Prospects of KAGRA" for October 2023 issue of The Astronomical Herald, which is a monthly magazine published by the Astronomical Society of Japan.
2023-09-12 (InternationalConferences)
- I gave a talk on the noise from birefringence fluctuations of mirrors at LIGO-Virgo-KAGRA collaboration meeting September 2023 held at Toyama International Conference Center. Slides are here (login required).
2023-09-07 (InternationalConferences)
- I gave an online talk on searches for noise from quantization of space-time and axion dark matter with LIGO at the workshop "Brainstorming new ideas for the km-scale facilities" held at Birmingham. Slides are here (login required).
2023-08-28 (Papers)
- We have found that the use of unstable inverted oscillators can dramatically accerelate the generation of gravity-incuded quantum entanglement. To test the quantum nature of gravity by measuring the entanglement between gravitationally coupled oscillators, it is necessary to make the coherence time larger than the entanglement generation time. Unstable inverted oscillators can meet this requirement most easily, and our idea opens up new possibilities for experimental tests, including experiments using optically levitated mirrors. The joint paper was posted on arXiv. arXiv:2308.14552
2023-07-19 (InternationalConferences)
- I gave an online talk on ultralight dark matter searches with laser interferometry at Amaldi 15. Slides are here.
2023-05-21 (JapaneseConferences)
- I gave a talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics" in Sapporo. I was finally able to attend the are meeting in person. Slides are here.
2023-05-18 (Seminars)
- I gave an inited seminar talk on future prospects of gravitational wave detector developments at the U-lab of Nagoya University. Slides are here.
2023-04-25 (Seminars)
- I gave an invited seminar talk on ultralight dark matter searches with laser interferometry for Copernicus Webinar and Colloquium Series. Slides are here.
2023-03-30 (Links)
- We held the Workshop on Very Light Dark Matter 2023. Thank you very much for wonderful talks and fruitful discussions.
2023-03-09 (InternationalConferences)
- I made a talk reporting the current status of the B01 group to search for dark matter using laser interferometers at Transformative Research Area "Dark Matter" FY2022 Symposium held at Kavli IPMU. It was my first in-person talk in three years! Slides are here.
2023-03-07 (Papers)
- We have posted our paper on arXiv, reporting the first results from DANCE to search for axion dark matter using an optical ring cavity. This is the first demonstration of polarization-based axion dark matter search with an optical cavity under no magnetic field. arXiv:2303.03594
2023-02-03 (Papers)
- A paper reviewing various experimental activities on mesoscopic quantum optomechanics within our French-Japanese QFilter project is published in AVS Quantum Science. AVS Quantum Sci. 5, 014403 (2023)
2022-11-04 (Documents)
- I wrote an introductory article "Laser interferometric search for dark matter" for High Energy News Vol. 41 No.3, which is a magazine published by Japan Association of High Energy Physicists.
2022-12-16 (JapaneseConferences)
- I gave an online talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics." Slides are here.
2022-10-26 (Documents)
- Our new approaches for dark matter search using laser interferomtry was focused in the December 2022 issue of Japanese science magazine "Newton".
2022-09-27 (InternationalConferences)
- I gave an online talk on the status of the experiment to demonstrate optical levitation of a mirror at the 4th QFilter Workshop held in Lyon, France. Slides are here.
2022-07-18 (Papers)
- We have found and experimentally demonstrated that the angular trapping of a tiny suspended mirror in a linear cavity is possible without additional active feedback control when the cavity geometry is carefully designed. This method solves radiation pressure induced angular instability issues in optomechanical experiments using tiny mirrors. The joint paper was published in Physical Review A. Phys. Rev. A 106, 013514 (2022)
2022-05-27 (JapaneseConferences)
- I gave an online talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics."Slides are here.
2022-04-01 (CV)
- I moved to California Institute of Technology as a Research Scientist at LIGO Laboratory.
2022-03-19 (Papers)
- Our research on axion dark matter search using gravitational wave detector KAGRA was featured in a newspaper article by Nikkei.
2022-03-17 (Seminars)
- I gave an invited online seminar on Dark matter Axion search with riNg Cavity Experiment DANCE at Cosmology Seminar hosted by Arizona State University. Slides are here.
2022-02-22 (JapaneseConferences)
- I gave an online invited talk on dark matter searches using gravitational wave detectors at the workshop "Gravitational Waves and Particle Physics" held at Osaka City University. Slides are here.
2022-02-21 (Papers)
- Three proceedings papers for TAUP2021 on our dark matter searches were published as Journal of Physics: Conference Series 2156, 012042 (2021), 2156, 012071 (2021) and 2156, 012182 (2021)

2021-12-11 (JapaneseConferences)
- I reported the activity status of B-DECIGO technology survey at 20th DECIGO Workshop held online. Slides are here.
2021-11-30 (Seminars)
- I gave an invited online seminar on Dark matter Axion search with riNg Cavity Experiment DANCE at Center for Experimental Nuclear Physics and Astrophysics (CENPA), University of Washington. Slides are here.
2021-11-17 (Seminars)
- I gave an invited online seminar on Dark matter Axion search with riNg Cavity Experiment DANCE at JPS Hokuriku Branch. Slides are here.
2021-10-31 (Papers)
- The TAUP2021 proceedings paper summarizing ultralight dark matter searches using KAGRA was posted on arXiv (arXiv:2111.00420). Two proceedings papers of dark matter axion search with ring cavity experiment DANCE were also posted (arXiv:2110.10607 and (arXiv:2110.12023).
2021-10-16 (JapaneseConferences)
- I gave an online talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics."Poster is here.
2021-09-27 (Links)
- We held the Workshop on Very Light Dark Matter 2021. Thank you very much for your active participation and fruitful discussions.
2021-09-16 (Papers)
- We have found that low mass axion dark matter can be searched with high sensitivity by using arm cavity transmitted beams of gravitational wave detectors. This is because the signal from axion is not cancelled out at the transmission ports, and this effect was not taken into account in previous studies. The joint paper was published in Physical Review D. Phys. Rev. D 104, 062008 (2021)
2020-09-15 (JapaneseConferences)
- I gave a talk on gauge boson dark matter search using KAGRA at the JPS meeting online. Slides are here.
2021-09-09 (InternationalConferences)
- I gave an online talks on axion and vector dakr matter searches using KAGRA at the LIGO-Virgo-KAGRA Collaboration Meeting. My talk was given at the dark matter direct detection panel session. Slides are here.
2021-09-02 (Papers)
- We have proposed a new method for evading quantum back-action by using the reflected light from an optomechanical cavity with a stiff optical spring. We also have successfully demonstrated the principle of this method by injecting classical noises. The joint paper was published as a Letter in Physical Review A. Phys. Rev. A 104, L031501 (2021)
2021-08-23 (InternationalConferences)
- I have uploaded the pre-recorded talk for 17th International Conference on Topics in Astroparticle and Underground Physics. My talk is on KAGRA searches for ultralight dark matter such as axions and gauge bosons. Slides are here.
2021-07-09 (InternationalConferences)
- I gave an online talk on the search for gauge boson dark matter using KAGRA data at the Sixteenth Marcel Grossmann Meeting. Slides are here.
2021-07-09 (InternationalConferences)
- I gave an online talk on the search for gauge boson dark matter using KAGRA data at the 8th KAGRA International Workshop. Slides are here.
2021-06-25 (JapaneseConferences)
- I gave an online talk to present the status of the experiment to search for axion dark matter with an optical ring cavity at the area meeting of PRESTO "Innovative optics and photonics."Slides are here.
2021-06-23 (InternationalConferences)
- I gave an online talk on the status of the experiment to demonstrate optical levitation of a mirror at the 3rd QFilter Workshop. Sildes are here.
2021-05-25
- This site was moved from WordPress on granite server to GitLab Pages. The old page can be accessed from here.
2021-05-24 (Papers)
- The special section on KAGRA and future gravitational wave observations was published in May 2021 issue of Progress of Theoretical and Experimental Physics. I contributed as one of the corresponding authors for the KAGRA paper overviewing the detector design and status upto O3. Papers on DECIGO and LISA Japan are also featured in this section. The link to the special section is here.
2021-04-14 (Seminars)
- I gave a seminar talk on gravitational wave astronomy and physics at Matsumoto Group, Gakushuin University. Slides are here.
2021-03-30 (Papers)
- We have demonstrated a dual-pass differential Fabry–Perot interferometer for future space gravitational wave detecor such as DECIGO. We have successfully confirmed that necessary functions such as the adjustment of the absolute arm length can be achieved. The joint paper was published in Classical and Quantum Gravity. Class. Quantum Grav. 38, 085018 (2021)
2021-03-19 (Papers)
- The joint paper summarizing the design and the result of initial performance test was published in Classical and Quantum Gravity. Class. Quantum Grav. 38, 085013 (2021)
2021-03-18 (Papers)
- We have pointed out that the sensitivity of interferometric gravitational wave detectors to ultralight vector dark matter can be drastically improved by considering the finite light-traveling time. We have also applied this for already existing LIGO constraints and updated the constraints by several orders of magnitude. The joint paper was published as a Letter in Physical Review D. Phys. Rev. D 103, L051702 (2021).
2021-03-17 (InternationalConferences)
- I gave online talks on optical levitation of a mirror (slides are here) and on the status of KAGRA (slides are here) at the LIGO-Virgo-KAGRA Collaboration Meeting.
2021-03-16 (Papers)
- KAGRA collaboration paper reporting the results from first cryogenic test operation was selected for CQG Highlights of 2019-20. Some of the best Classical and Quantum Gravity articles published in 2019 and the first half of 2020 were selected by the editorial board. I wrote the paper as one of the corresponding authors.
2021-03-05 (Seminars)
- We have hold an online joint seminar between Peter Wolf's group in SYRTE, Observatoire de Paris. I gave an talk introducing our activities on laser interferometric searches for ultralight dark matter. Slides are here.
2021-03-04 (JapaneseConferences)
- I gave an online talk and had a group discussion on my research project "New dark matter search with high precision polarization measurements" at 14th Cross-PRESTO meeting. Slides are here.
2021-02-06 (InternationalConferences)
- I gave an online talk introducing B01 group on laser interferometers at the Transformative Research Area "Dark Matter" Symposium. Slides are here.
2021-01-29
- We have launched our website for JSPS Grant-in-Aid for Transformative Research Areas (A) on dark matter. We are also calling for Publicly Offered Research.
2021-01-20 (Documents)
- January 2021 issue of Rigakubu News was published. I wrote an article introducing a book on relativity and the universe.
2021-01-14 (Seminars)
- I gave an online seminar talk on the optical levitation of a mirror at the Quantum Machines Seminar, OIST. Slides are here.
2020-12-20 (InternationalConferences)
- I gave an online talk on the expectations for the sensitivity of KAGRA in O4 observing run at the 7th KAGRA International Workshop. Slides are here.
2020-11-30
- We invite applicants for two postdoc positions on dark matter search related to JSPS Grant-in-Aid for Transformative Research Areas "Dark matter." Advertisement can be found here.
2020-11-30 (Papers)
- We have succeeded in demonstrating the optical trapping of the transversal motion of a optically levitated mirror. We have experimentally proved that the optical levitation of a mirror using the sandwich configuration proposed by us is realizable. The joint paper was published as Phys. Rev. A 102, 053520 (2020)
2020-11-28 (JapaneseConferences)
- I gave an online talk on my research project "New dark matter search with high precision polarization measurements" at the Kick-off meeting of PRESTO "Innovative optics and photonics." Slides are here.
2020-11-21 (JapaneseConferences)
- I gave an online talk on the possibility of gravitational wave observation with ultra-precision spacecraft formation flying mission SILVIA at the 19th DECIGO Workshop. Slides are here.
2020-11-19 (CV)
- JSPS Grant-in-Aid for Transformative Research Areas (A) "What is dark matter? - Comprehensive study of the huge discovery space in dark matter" has started. I'm a PI of one of the planned research, "Ultralight dark matter search using gravitational wave detectors and laser interferometer experiments"
2020-11-17 (InternationalConferences)
- I gave an online talk on the future plans of KAGRA at the KAGRA-OzGrav joint meeting. Slides are here.
2020-11-09 (Papers)
- The joint paper summarizing the design and characteristics of compact integrated displacement sensors and actuators used for vibration isolation systems in KAGRA was published as Rev. Sci. Instrum. 91, 115001 (2020).
2020-11-02 (Papers)
- We proposed a new method to search for ultralight vector dark matter using auxiliary length channels of gravitational wave detectors. Although auxiliary length channels do not contain gravitational wave signal, they could have signals from dark matter. By applying this method to KAGRA, dark matter search with sensitivity improvement by more than an order of magnitude is possible. Our proposal opens up new possibilities for dark matter searches with gravitational wave detectors. My paper was published as Phys. Rev. D 102, 102001 (2020).
2020-10-28 (JapaneseConferences)
- I gave an online talk on the possibility of gravitational wave observation with ultra-precision spacecraft formation flying mission SILVIA at the JSASS meeting. Slides are here.
2020-10-19 (CV)
- I was awarded the grant from JST PRESTO "Innovative optics and photonics." Thank you very much.
2020-10-19 (Papers)
- Our proposal to search for axion dark matter using KAGRA gravitational wave detector was featured in the newspaper article in The Asahi Shimbun.
2020-09-20
- I'm giving a lab tour in the virtual campus tour of the 93th Gogatsusai. The link to YouTube video is here.
2020-09-16 (JapaneseConferences)
- I gave a talk on ultralight dark matter search using auxiliary length channels of gravitational wave detectors at the JPS meeting online. Slides are here.
2020-07-25
- My webpage was renewed! I now use WordPress instead of Pukiwiki. The old page can be accessed from here.
2020-07-24 (Papers)
- We studied how different upgrade technologies improve the sensitivity of KAGRA at various detector bands. Our study paves the way to designing future cryogenic gravitational wave detectors for various astrophysical targets. My paper was published in Physical Review D. Phys. Rev. D 102, 022008 (2020)
2020-07-13 (Seminars)
- I gave a talk on ultralight dark matter searches with laser interferometric gravitational wave detectors at the seminar organized by Riken iTHEMS Dark Matter Working Group. Slides are here.
2020-06-18 (Papers)
- We wrote a review paper on milligram scale optomechanical systems. We compared the feasibility of reaching the quantum regime with a pendulum, torsion pendulum, and optically levitated mirror. The paper was published in The European Physical Journal D as a contribution to the Topical Issue on "Quantum Technologies for Gravitational Physics." The European Physical Journal D 74, 126 (2020)
2020-06-02 (Papers)
- We invented a new method to optimize quantum noise of the interferometer which employs quantum locking technique. The joint paper was published in Physics Letters A. Physics Letters A 384, 126626 (2020)
2020-06-01 (Documents)
- A Japanese book on relativity and universe was published from Asakura Publishing. I wrote sections on the test of the invariance of the speed of light and various ways for gravitational wave observation.
2020-05-12 (Papers)
- We wrote a paper overviewing the detector design and status of KAGRA. I contributed as one of the corresponding authors. It was submitted to Progress of Theoretical and Experimental Physics for an issue focusing on gravitational waves. arXiv:2005.05574
2020-03-21 (Papers)
- Proceedings papers for TAUP2019 on DANCE project to search for axion dark matter with optical ring cavity, and the project to search for axion dark matter with interferometric gravitational wave detectors were published as Journal of Physics: Conference Series 1468, 012032 (2020) and 1468, 012027 (2020).
2020-02-25 (InternationalConferences)
- I gave a talk on the experiment to demonstrate optical levitation of a mirror at the 2nd QFilter Workshop, Kyoto University. Sildes are here.
2020-01-24 (Documents)
- A Japanese book on advances in physical science in 2020 was published from Maruzen Publishing. I wrote an article on KAGRA gravitational wave telescope.
2020-01-20 (Documents)
- January 2020 issue of Rigakubu News was published. I wrote an article on axion dark matter detection with laser interferometric gravitational wave detectors.
2020-01-17 (Papers)
- We have succeeded in developing a 10-mg torsion pendulum which has the best torque sensitivity as a miligram scale torsion pendulum. Such a massive optomechanical device can shed light on macroscopic quantum mechanics and gravitational physics. The joint paper was published as Phys. Rev. A 101, 011802(R) (2020).
2020-01-14 (Links)
- I attended the Global Young Scientists Summit 2020 in Singapore. Around 280 young researchers are nominated and gathered around the world. See this YouTube video for highlights.
2020-01-13 (Papers)
- We have developed an arm length stabilization system for KAGRA, and successfully demonstrated the lock acquisition of the arm cavities. Our new scheme is scalable to future longer baseline gravitational wave detectors. The joint paper was published as Classical and Quantum Gravity 37, 035004 (2020).
2020-01-09 (InternationalConferences)
- I gave an invited lecture on various searches for non-standard physics with laser interferometers at The First School on Quantum Sensors for Fundamental Physics, Durham University. Slides are here.
2020-01-01 (Papers)
- Proceedings paper for TAUP2017 on the status of KAGRA was finally published as Journal of Physics: Conference Series 1342, 012014 (2020). I wrote the manuscript as a corresponding author in 2017.
2019-12-29 (Papers)
- Our research on axion dark matter search using gravitational wave detector KAGRA was featured in a newspaper article by Nikkei.
2019-12-27 (JapaneseConferences)
- I gave an invited talk on the status and future prospects of gravitational wave observations at 32th Rironkon symposium at National Astronomical Observatory of Japan. Slides are here.
2019-12-10 (Seminars)
- I gave a seminar on optical levitation of a mirror for probing macroscopic quantum mechanics at Iwamoto Lab, the Institute of Industrial Science, University of Tokyo. Slides are here.
2019-11-20 (Papers)
- Our research on axion search with gravitational wave detectors was featured on the official YouTube channel of the School of Science, University of Tokyo.
2019-11-10 (JapaneseConferences)
- I gave a talk on small scale space gravitational wave telescope at the 18th DECIGO Workshop held at Kyoto University. Slides are here.
2019-11-09 (JapaneseConferences)
- I gave an invited talk on quantum techniques for gravitational wave observations at Quantum Electronics workshop held at Yamanaka Ryo. Slides are here.
2019-10-30 (Papers)
- We have estimated the effect of substrate inhomogeneity of KAGRA sapphire mirrors to the performance of KAGRA as a gravitational wave telescope, using interferometer simulations. The joint paper was published as Phys. Rev. D 100, 082005 (2019).
2019-10-23 (InternationalConferences)
- I gave an invited talk on the status and future prospects of KAGRA at Multi-dimensional Modeling and Multi-Messenger observation from Core-Collapse Supernovae, Fukuoka University. Slides are here.
2019-10-16 (CV)
- I was awarded the Grant for Basic Science Research Projects from Sumitomo Foundation. Thank you very much.
2019-10-15 (InternationalConferences)
- I presented a poster discussing estimated sensitivity evolution of KAGRA at GWPAW2019, Tokyo. Poster is here.
2019-10-09 (Seminars)
- I gave a seminar on laser interferometric gravitational wave detectors and macroscopic quantum mechanics at Institute of Cosmophysics, Kobe University. Slides are here.
2019-09-27 (Papers)
- We have designed and developed a laser modulation system which enables a low noise control of interferometric gravitational wave detectors, and successfully demonstrated the proof-of-principle. The joint paper was published as Classical and Quantum Gravity 36, 205009 (2019).
2019-09-20 (JapaneseConferences)
- I gave a talk on small scale space gravitational wave telescope at the JPS meeting held at Yamagata University. Slides are here.
2019-09-13 (Papers)
- We proposed a new method to search for axion dark matter using an optical linear cavity. Our method can be applied to linear cavities used in interferometric gravitational wave detectors and axion search can be done simultaneously with gravitational wave observations. The joint paper was published as Phys. Rev. Lett. 123, 111301 (2019), and featured in UTokyo FOCUS.
2019-09-09 (InternationalConferences)
- I gave a talk on DANCE experiment, which aims to search for axion dark matter with an optical ring cavity, at TAUP2019, Toyama. Slides are here.
2019-08-20 (Papers)
- We have found that separation of gravitational wave polarizations is possible with future gravitational wave detectors even if the number of detectors is less than number of polarization modes. This is because the orientation of the detector will change significantly during the observation of gravitational waves from compact binaries. The joint paper was published as Phys. Rev. D 100, 042001 (2019).
2019-08-05 (Seminars)
- I gave a seminar on various fundamental physics experiments using laser interferometry at Yorita Lab, Waseda University. Slides are here.
2019-07-26 (InternationalConferences)
- I gave invited lectures on laser interferometry for gravitational wave observations at the summer school held at TianQin Research Center, Sun Yat-sen University. Slides part 1, part 2, part 3, part 4.
2019-07-23 (Papers)
- I wrote a paper presenting results from KAGRA's first cryogenic test operation in April and May 2018 as one of the corresponding authors. The paper was published as Classical and Quantum Gravity 36, 165008 (2019). The paper was featured in Science News magazine article.
2019-07-10 (InternationalConferences)
- I gave a talk on prospects for the upgrade of KAGRA at 13th Edoardo Amaldi Conference on Gravitational Waves, Valencia. Slides are here.
2019-07-06 (JapaneseConferences)
- I gave a talk on axion dark matter search using laser interferometers at Darkon 2019 held at Waseda University. Slides are here.
2019-06-18 (Seminars)
- I gave a seminar on the present status and future prospects of KAGRA at ICRR Seminar. Slides are here.
2019-06-07 (Papers)
- Proceedings paper for MG15 on prospects for the upgrade of KAGRA was posted as arXiv:1906.02866.
2019-05-08 (Papers)
- Our research on mg-scale gravity sensor with Tohoku University was featured on the official YouTube channel of the School of Science, University of Tokyo.
2019-04-12 (Papers)
- The paper on vibration isolation system for power recycling mirrors in KAGRA was published as Classical and Quantum Gravity 36, 095015 (2019).
2019-03-19 (InternationalConferences)
- We had The 1st QFilter Workshop at Laboratoire Kastler Brossel, Paris. I gave a talk on optical levitation of a mirror. QFilter project is France-Japan joint research project which started last year. Slides are here and here.
2019-03-17 (JapaneseConferences)
- I gave a talk on axion dark matter search using an optical cavity at the JPS meeting held at Kyushu University. Slides are here.
2019-02-28 (JapaneseConferences)
- I gave invited lectures on interferometric gravitational wave observations at the 3rd Workshop on Gravity and Cosmology by Young Researchers at Kyoto University. Slides are here and here.
2019-02-19 (Papers)
- We have developed a 7-mg suspended mirror which has enough displacement sensitivity to probe mg-scale gravity. The demonstration paves the way to probe gravitational coupling between masses in quantum regimes. The joint paper was published in Phys. Rev. Lett. 122, 071101 (2019), and featured in Physics.
2019-01-17 (InternationalConferences)
- I gave an invited talk on the status of KAGRA at the Conference on Multi-messenger Astronomy in the Era of LIGO-India, Khandala. I also had an interview with LIGO-India Education and Public Outreach team. Slides are here.
2019-01-08 (Papers)
- I wrote an introductory article on KAGRA as one of the corresponding authors. The article was published as Perspective in Nature Astronomy 3, 35 (2019).
2018-11-28 (Papers)
- Our paper proposing the use of optical ring cavity for axion search was selected as Research Highlight in Nature Photonics.
2018-10-31 (Lectures)
- I gave a lecture on current status and prospects of gravitational wave observations at Junten High School. Slides are here.
2018-10-20 (Lectures)
- I gave a lecture on gravitational wave observations and motivations of fundamental science at Azabu High School. Slides are here.
2018-10-17 (Papers)
- We proposed a new method to search for axion dark matter using an optical ring cavity. Compared with previous methods, the sensitivity can be improved by several orders of magnitude. The joint paper was published as Phys. Rev. Lett. 121, 161301 (2018).
2018-09-15 (JapaneseConferences)
- I gave a talk on KAGRA upgrades at the JPS meeting held at Shinshu University. Slides are here.
2018-07-12 (Papers)
- We studied the separability of non-tensorial polarizations of gravitational waves from compact binary coalescences. We showed that the number of detectors should be at least as much as the number of the polarizations to distinguish the polarizations. The joint paper was published as Phys. Rev. D 98, 022008 (2018).
2018-07-02 (InternationalConferences)
- I gave a talk on prospects for sensitivity improvement of KAGRA at the 15th Marcel Grossmann Meeting, Rome. Slides are here.
2018-06-30 (InternationalConferences)
- I gave a talk on sensitivity optimization and upgrade plans of KAGRA at the 4th KAGRA International Workshop, Seoul. Slides are here.
2018-06-12 (Papers)
- Using particle swarm optimization, we showed that the detection range and the sky localization of binary neutron stars by KAGRA can be further improved. Our results clearly showed that particle swarm optimization is useful for designing the sensitivity of cryogenic gravitational wave detectors. My paper was published as Phys. Rev. D 97, 122003 (2018).
2018-05-14 (InternationalConferences)
- I gave a talk on sensitivity optimization of cryogenic gravitational wave detectors at GWADW2018, Alaska. Slides are here.
2018-05-03 (Papers)
- We succeeded in formalizing a method for calculating suspension thermal noise under non-uniform temperature. The joint paper was published as Phys. Rev. D 97, 102001 (2018).
2018-05-03 (Papers)
- We systematically investigated seismic cross-coupling noise in torsion pendulums and experimentally confirmed our model. We also succeeded in actually reducing the noise. The joint paper was published as Phys. Rev. D 97, 104003 (2018).
2018-04-26 (Papers)
- Observing scenario paper by LIGO, Virgo and KAGRA was published as Living Reviews in Relativity 21, 3 (2018). The paper summarizes the observation plans of each detector and prospects for sky localization of binary neutron stars.
2018-04-10 (Calculators)
- I made a calculator for deriving laser power from the output of the popular photodiode.
2018-03-22 (JapaneseConferences)
- I gave a talk on particle swarm optimization of the sensitivity of KAGRA at the JPS meeting held at Tokyo University of Science. Slides are here.
2018-01-19 (Papers)
- KAGRA collaboration paper on the construction and the first test operation in March and April 2016 was published as Progress of Theoretical and Experimental Physics 2018, 013F01 (2018). I mainly wrote Section 5.1, which describes the details of the first test run.
2017-11-28 (Papers)
- Proceedings of the MG14 Meeting was published. It includes my paper on the higher order test of Lorentz invariance.
2017-10-26 (InternationalConferences)
- I gave an invited talk on laser interferometry for gravitational wave astronomy at IONS2017 held at OIST. Slides are here.
2017-10-25 (Papers)
- We developed an interferometer control model and successfully designed the actuation parameters for all the KAGRA mirrors to have sufficient force range as well as to have sufficiently small noise. My paper was published as Classical and Quantum Gravity 34, 225001 (2017).
2017-09-21 (JapaneseConferences)
- I gave a talk on reaching the standard quantum limit by the optical levitation of a macroscopic mirror at the JPS meeting held at Iwate University. Slides are here.
2017-09-13 (JapaneseConferences)
- I gave a talk on sensitivity improvement plans for KAGRA at the JPS meeting held at Utsunomiya University. Slides are here.
2017-07-25 (InternationalConferences)
- I gave a KAGRA status talk at TAUP2017, Laurentian University, Canada. Slides are here.
2017-06-16 (Seminars)
- I gave a seminar talk on the status and future prospects of gravitational wave observations at Research Center for Neutrino Science, Tohoku University. Slides are here.
2017-06-08 (Papers)
- We proposed a new method to optically levitate a mg-scale mirror, and showed that reaching the standard quantum limit is feasible with this method. My paper was published as Optics Express 25, 13799 (2017).
2017-05-22 (InternationalConferences)
- I gave a talk on KAGRA upgrades at the 3rd KAGRA International Workshop, Academia Sinica, Taiwan. Slides are here.
2017-05-09 (InternationalConferences)
- I gave a talk on KAGRA upgrades at GWADW2017, Hamilton Island, Australia. Slides are here.
2017-04-20 (InternationalConferences)
- I gave a talk on optical cavity tests of Lorentz invariance at LNPC2017, Pacifico Yokohama, Japan. Slides are here.
2017-03-30 (InternationalConferences)
- I gave some talks at 16th KAGRA Face to Face Meeting, Niigata University, Japan.
2017-03-17 (JapaneseConferences)
- I gave a talk on the mirror actuator design for KAGRA at the JPS meeting held at Osaka University. Slides are here.
2017-02-28 (InternationalConferences)
- I gave a KAGRA status talk at ELiTES: 5th general meeting, Europa House, Tokyo. Slides are here.

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