![Keiko Kokeyama BSc, MSc, PhD, FHEA](https://profiles-cardiff.imgix.net/attachments/4420?w=200&h=200&auto=format&crop=faces&fit=crop&q=90")
Dr Keiko Kokeyama
(she/her)
BSc, MSc, PhD, FHEA
- Available for postgraduate supervision
Teams and roles for Keiko Kokeyama
Senior Lecturer
Gravity Exploration Institute
Overview
I am an experimental physicist in gravitational-wave detector science. Since the monumental first detection of gravitational waves from a binary black hole merger in 2015, followed by a neutron star merger in 2017, it has been a golden age of gravitational-wave astrophysics. The gravitational wave detectors are laser interferometers to detect distortions of space-time caused by gravitational waves, coming from somewhere in the universe. Because the distortions of space-time are extremely small, typically an order of 10^(-21) m (0.000...21 zeros... 001 m, one-millionth of a proton diameter), the gravitational-wave detectors are extremely sensitive, as precise as Heisenberg's uncertainty limit allows. I worked on two large-scale detectors, the LIGO Livingston detector and the KAGRA detector, to make the detector work and improve the sensitivity to run the astrophysical observations. Because the instruments must be very sensitive, many state-of-the-art technologies are being developed and implemented. Currently, at Cardiff, I work on new technologies to make future detectors more sensitive. We want to observe more numbers of black hole or neutron star mergers from even the father universe.
Please visit our website for more information: https://exp.gravity.cf.ac.uk/
Publication
2025
- Abac, A. G. et al., 2025. Search for continuous gravitational waves from known pulsars in the first part of the fourth LIGO-Virgo-KAGRA observing run. The Astrophysical Journal 983 (2) 99. (10.3847/1538-4357/adb3a0)
- Abac, A. G. et al., 2025. Search for gravitational waves emitted from SN 2023ixf. The Astrophysical Journal 985 (2) 183. (10.3847/1538-4357/adc681)
- Aiello, L. et al. 2025. Swift-BAT GUANO follow-up of gravitational-wave triggers in the Third LIGO–Virgo–KAGRA observing run. The Astrophysical Journal 980 (2) 207. (10.3847/1538-4357/ad9749)
- Aiello, L. et al., 2025. Tests of general relativity with GWTC-3. Physical Review D 112 084080. (10.1103/PhysRevD.112.084080)
- Akutsu, T. et al., 2025. Identification of noise-associated glitches in KAGRA O3GK with hierarchical veto. Progress of Theoretical and Experimental Physics 2025 (8) 083F01. (10.1093/ptep/ptaf093)
- Al-Shammari, S. et al. 2025. GW241011 and GW241110: Exploring binary formation and fundamental physics with asymmetric, high-spin black hole coalescences. The Astrophysical Journal Letters 993 L21. (10.3847/2041-8213/ae0d54)
- Al-Shammari, S. et al. 2025. GW231123: A binary black hole merger with total mass 190–265 M⊙. The Astrophysical Journal Letters 993 (1) L25. (10.3847/2041-8213/ae0c9c)
- al-Shammari, S. et al. 2025. All-sky search for short gravitational-wave bursts in the first part of the fourth LIGO-Virgo-KAGRA observing run. Physical Review D 112 102005. (10.1103/wjdz-jdby)
- Al-Shammari, S. et al. 2025. GWTC-4.0: An introduction to version 4.0 of the Gravitational-Wave Transient Catalog. The Astrophysical Journal Letters 995 (1) L18. (10.3847/2041-8213/ae0c06)
- Amarasinghege, O. et al. 2025. GW250114: Testing Hawking’s area law and the Kerr nature of black holes. Physical Review Letters 135 111403. (10.1103/kw5g-d732)
- Iwaguchi, S. et al., 2025. Proof-of-principle experiment on a displacement-noise-free neutron interferometer for gravitational wave detection. Physical Review D (particles, fields, gravitation, and cosmology) 112 102002. (10.1103/yg4l-cj1t)
- Patra, A. et al. 2025. Broadband limits on stochastic length fluctuations from a pair of table-top interferometers. Physical Review Letters 135 101402. (10.1103/61j9-cjkk)
- Tanioka, S. , Pearce, T. and Kokeyama, K. 2025. Development of a polarimetry method toward in situ substrate birefringence characterization of ground-based gravitational wave detectors. Review of Scientific Instruments 96 (7) 074503. (10.1063/5.0279006)
2024
- Abac, A. G. et al., 2024. Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo. The Astrophysical Journal 973 (2) 132. (10.3847/1538-4357/ad65ce)
- Abac, A. G. et al., 2024. A search using GEO600 for gravitational waves coincident with fast radio bursts from SGR 1935+2154. The Astrophysical Journal 977 (2) 255. (10.3847/1538-4357/ad8de0)
- Abac, A. G. et al., 2024. Observation of gravitational waves from the coalescence of a 2.5–4.5 M ⊙ compact object and a neutron star. The Astrophysical Journal Letters 970 (2) L34. (10.3847/2041-8213/ad5beb)
- Abac, A. et al., 2024. Ultralight vector dark matter search using data from the KAGRA O3GK run. Physical Review D (particles, fields, gravitation, and cosmology) 110 (4) 042001. (10.1103/physrevd.110.042001)
- Abbott, R. et al., 2024. Search for gravitational-lensing signatures in the full third observing run of the LIGO–Virgo network. Astrophysical Journal 970 (191)(10.3847/1538-4357/ad3e83)
- Abbott, R. et al., 2024. Search for gravitational-wave transients associated with magnetar bursts in Advanced LIGO and Advanced Virgo data from the third observing run. The Astrophysical Journal 966 (1) 137. (10.3847/1538-4357/ad27d3)
- Fletcher, C. et al., 2024. A joint Fermi-GBM and Swift-BAT analysis of Gravitational-wave candidates from the third Gravitational-wave Observing Run. The Astrophysical Journal 964 (2) 149. (10.3847/1538-4357/ad1eed)
- Sakai, Y. et al., 2024. Training process of unsupervised learning architecture for gravity spy dataset. Annalen der Physik 536 (2) 2200140. (10.1002/andp.202200140)
- Wang, H. et al., 2024. Characterization of birefringence inhomogeneity of KAGRA sapphire mirrors from transmitted wavefront error measurements. Physical Review D (particles, fields, gravitation, and cosmology) 110 (8) 082007. (10.1103/physrevd.110.082007)
2023
- Abbott, R. et al., 2023. Constraints on the cosmic expansion history from GWTC–3. Astrophysical Journal 949 (2) 76. (10.3847/1538-4357/ac74bb)
- Abbott, R. et al., 2023. Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO. Astrophysical Journal Supplement 267 (2) 29. (10.3847/1538-4365/acdc9f)
- Abe, H. et al., 2023. Noise subtraction from KAGRA O3GK data using Independent Component Analysis. Classical and Quantum Gravity 40 (8) 085015. (10.1088/1361-6382/acc0cb)
- Akutsu, T. et al., 2023. Input optics systems of the KAGRA detector during O3GK. Progress of Theoretical and Experimental Physics 2023 (2) 023F01. (10.1093/ptep/ptac166)
2022
- Abbott, R. et al., 2022. Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO-Virgo Run O3b. Astrophysical Journal 928 (2) 186. (10.3847/1538-4357/ac532b)
- Abbott, R. et al., 2022. Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo. Astronomy & Astrophysics 659 A84. (10.1051/0004-6361/202141452)
- Abbott, R. et al., 2022. Constraints on dark photon dark matter using data from LIGO's and Virgo's third observing run. Physical Review D 105 (6) 063030. (10.1103/PhysRevD.105.063030)
- Abbott, R. et al., 2022. Model-based cross-correlation search for gravitational waves from the low-mass x-ray binary scorpius x-1 in ligo o3 data. Astrophysical Journal Letters 941 (2) L30. (10.3847/2041-8213/aca1b0)
- Abbott, R. et al., 2022. Searches for gravitational waves from known pulsars at two harmonics in the second and third LIGO-Virgo observing runs. Astrophysical Journal 935 (1) 1. (10.3847/1538-4357/ac6acf)
- Abe, H. et al., 2022. Performance of the KAGRA detector during the first joint observation with GEO 600 (O3GK). Progress of Theoretical and Experimental Physics ptac093. (10.1093/ptep/ptac093)
- Abe, H. et al., 2022. The current status and future prospects of KAGRA, the large-scale cryogenic gravitational wave telescope built in the Kamioka underground. Galaxies 10 (3) 63. (10.3390/galaxies10030063)
- Fairhurst, S. et al. 2022. All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data. Physical Review D 106 (10)(10.1103/PhysRevD.106.102008)
- Sakai, Y. et al., 2022. Unsupervised learning architecture for classifying the transient noise of interferometric gravitational-wave detectors. Scientific Reports 12 (1) 9935. (10.1038/s41598-022-13329-4)
2021
- Abbott, R. et al., 2021. All-sky search for short gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run. Physical Review D 104 122004. (10.1103/PhysRevD.104.122004)
- Akutsu, T. et al., 2021. Overview of KAGRA: Calibration, detector characterization, physical environmental monitors, and the geophysics interferometer. Progress of Theoretical and Experimental Physics 2021 (5) 05A102. (10.1093/ptep/ptab018)
- Akutsu, T. et al., 2021. Overview of KAGRA: Detector design and construction history. Progress of Theoretical and Experimental Physics 2021 (5) 05A101. (10.1093/ptep/ptaa125)
- Akutsu, T. et al., 2021. Overview of KAGRA: KAGRA science. Progress of Theoretical and Experimental Physics 2021 (5) 05A103. (10.1093/ptep/ptaa120)
- Akutsu, T. et al., 2021. Radiative cooling of the thermally isolated system in KAGRA gravitational wave telescope. Journal of Physics: Conference Series 1857 (1) 012002. (10.1088/1742-6596/1857/1/012002)
- Kawamura, S. et al., 2021. Current status of space gravitational wave antenna DECIGO and B-DECIGO. Progress of Theoretical and Experimental Physics 2021 (5) 05A105. (10.1093/ptep/ptab019)
2020
- Abbott, B. P. et al., 2020. Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA. Living Reviews in Relativity 23 (1) 3. (10.1007/s41114-020-00026-9)
- Akutsu, T. et al., 2020. An arm length stabilization system for KAGRA and future gravitational-wave detectors. Classical and Quantum Gravity 37 (3) 035004. (10.1088/1361-6382/ab5c95)
- Yamada, R. et al., 2020. Optimization of quantum noise by completing the square of multiple interferometer outputs in quantum locking for gravitational wave detectors. Physics Letters A 384 (26) 126626. (10.1016/j.physleta.2020.126626)
- Zhu, Z. -. et al., 2020. Application of independent component analysis to the iKAGRA data. Progress of Theoretical and Experimental Physics 2020 (5) 053F01. (10.1093/ptep/ptaa056)
2019
- Akiyama, Y. et al., 2019. Vibration isolation system with a compact damping system for power recycling mirrors of KAGRA. Classical and Quantum Gravity 36 (9) 095015. (10.1088/1361-6382/ab0fcb)
- KAGRA collaboration, and Kokeyama, K. 2019. KAGRA: 2.5 generation interferometric gravitational wave detector. Nature Astronomy 3 (1), pp.35-40. (10.1038/s41550-018-0658-y)
- Yamamoto, K. et al., 2019. Design and experimental demonstration of a laser modulation system for future gravitational-wave detectors. Classical and Quantum Gravity 36 (20) 205009. (10.1088/1361-6382/ab4489)
2018
- Akutsu, T. et al., 2018. Construction of KAGRA: an underground gravitational-wave observatory. Progress of Theoretical and Experimental Physics 2018 (1) 013F01. (10.1093/ptep/ptx180)
- Kokeyama, K. et al. 2018. Demonstration for a two-axis interferometric tilt sensor in KAGRA. Physics Letters A 382 (29), pp.1950-1955. (10.1016/j.physleta.2018.05.004)
2016
- Abbott, B. P. et al., 2016. Astrophysical implications of the binary black hole merger GW150914. Astrophysical Journal Letters 818 (2) L22. (10.3847/2041-8205/818/2/L22)
- Abbott, B. P. et al., 2016. GW150914: the advanced LIGO detectors in the era of first discoveries. Physical Review Letters 116 (13) 131103. (10.1103/PhysRevLett.116.131103)
- Abbott, B. P. et al., 2016. Observation of gravitational waves from a binary black hole merger. Physical Review Letters 116 (6) 061102. (10.1103/PhysRevLett.116.061102)
- Mueller, C. L. et al., 2016. The advanced LIGO input optics. Review of Scientific Instruments 87 (1) 014502. (10.1063/1.4936974)
2015
- Evans, M. et al., 2015. Observation of Parametric Instability in Advanced LIGO. Physical Review Letters 114 (16) 161102. (10.1103/PhysRevLett.114.161102)
2014
- Kokeyama, K. et al. 2014. Residual amplitude modulation in interferometric gravitational wave detectors. Journal of the Optical Society of America A 31 (1), pp.81-88. (10.1364/JOSAA.31.000081)
- Staley, A. et al., 2014. Achieving resonance in the advanced LIGO gravitational-wave interferometer. Classical and Quantum Gravity 31 (24) 245010. (10.1088/0264-9381/31/24/245010)
2013
- Lodhia, D. et al., 2013. Interferometer phase noise due to beam misalignment on diffraction gratings. Optics Express 21 (24), pp.29578-29591. (10.1364/OE.21.029578)
2012
- Fulda, P. et al., 2012. Review of the Laguerre-Gauss mode technology research program at Birmingham. Presented at: 9th Edoardo Amaldi Conference and Numerical Relativity - Data Analysis Meeting (Amaldi 9/NRDA 2011) Cardiff, Wales 10-15 July 2011. Vol. 363.IOP Publishing: Conference Series. , pp.012010. (10.1088/1742-6596/363/1/012010)
2011
- Bond, C. et al., 2011. Higher order Laguerre-Gauss mode degeneracy in realistic, high finesse cavities. Physical Review D - Particles, Fields, Gravitation and Cosmology 84 (10) 102002. (10.1103/PhysRevD.84.102002)
2010
- Fulda, P. et al., 2010. Experimental demonstration of higher-order Laguerre-Gauss mode interferometry. Physical Review D - Particles, Fields, Gravitation and Cosmology 82 (1) 012002. (10.1103/PhysRevD.82.012002)
- Somiya, K. , Kokeyama, K. and Nawrodt, R. 2010. Remarks on thermoelastic effects at low temperatures and quantum limits in displacement measurements. Physical Review D, Particles and fields 63 (8) 127101. (10.1103/PHYSREVD.82.127101)
2009
- Kokeyama, K. et al. 2009. Development of a displacement- and frequency-noise-free interferometer in a 3D configuration for gravitational wave detection. Physical Review Letters 103 171101. (10.1103/PhysRevLett.103.171101)
2008
- Kokeyama, K. et al. 2008. The experimental plan of displacement- and frequency-noise free laser interferometer. Presented at: The Seventh Edoardo Amaldi Conference On Gravitational Waves (amaldi7) Sydney, Australia 8-14 July 2007. Vol. 122.IOP Publishing: Conference Series. (10.1088/1742-6596/122/1/012022)
- Kokeyama, K. et al. 2008. Development of a signal-extraction scheme for resonant sideband extraction. Classical and Quantum Gravity 25 (23) 235013. (10.1088/0264-9381/25/23/235013)
- Sato, S. et al., 2008. Demonstration of displacement-noise-free interferometry using bi-directional Mach-Zehnder interferometers. Classical and Quantum Gravity 25 (11) 114031. (10.1088/0264-9381/25/11/114031)
2007
- Sato, S. et al., 2007. Diagonalization of the length sensing matrix of a dual recycled laser interferometer gravitational wave antenna. Physical Review D - Particles, Fields, Gravitation and Cosmology 75 (8) 082004. (10.1103/PhysRevD.75.082004)
- Sato, S. et al., 2007. Demonstration of displacement- and frequency-noise-free laser interferometry using bidirectional Mach-Zehnder Interferometers. Physical Review Letters 98 (14) 141101. (10.1103/PhysRevLett.98.141101)
2006
- Chen, Y. et al., 2006. Interferometers for displacement-noise-free gravitational-wave detection. Physical Review Letters 97 (15) 151103. (10.1103/PhysRevLett.97.151103)
- Kawazoe, F. et al., 2006. The experimental plan of the 4m resonant sideband extraction prototype for the LCGT. Journal of Physics: Conference Series 32 , pp.380-385. 058. (10.1088/1742-6596/32/1/058)
- Kokeyama, K. et al. 2006. Downselect of the signal extraction scheme for LCGT. Journal of Physics: Conference Series 32 065. (10.1088/1742-6596/32/1/065)
- Sato, S. et al., 2006. Diagonalizing sensing matrix of broadband RSE. Journal of Physics: Conference Series 32 , pp.470-475. 072. (10.1088/1742-6596/32/1/072)
Articles
- Abac, A. G. et al., 2024. Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo. The Astrophysical Journal 973 (2) 132. (10.3847/1538-4357/ad65ce)
- Abac, A. G. et al., 2024. A search using GEO600 for gravitational waves coincident with fast radio bursts from SGR 1935+2154. The Astrophysical Journal 977 (2) 255. (10.3847/1538-4357/ad8de0)
- Abac, A. G. et al., 2024. Observation of gravitational waves from the coalescence of a 2.5–4.5 M ⊙ compact object and a neutron star. The Astrophysical Journal Letters 970 (2) L34. (10.3847/2041-8213/ad5beb)
- Abac, A. G. et al., 2025. Search for continuous gravitational waves from known pulsars in the first part of the fourth LIGO-Virgo-KAGRA observing run. The Astrophysical Journal 983 (2) 99. (10.3847/1538-4357/adb3a0)
- Abac, A. G. et al., 2025. Search for gravitational waves emitted from SN 2023ixf. The Astrophysical Journal 985 (2) 183. (10.3847/1538-4357/adc681)
- Abac, A. et al., 2024. Ultralight vector dark matter search using data from the KAGRA O3GK run. Physical Review D (particles, fields, gravitation, and cosmology) 110 (4) 042001. (10.1103/physrevd.110.042001)
- Abbott, B. P. et al., 2016. Astrophysical implications of the binary black hole merger GW150914. Astrophysical Journal Letters 818 (2) L22. (10.3847/2041-8205/818/2/L22)
- Abbott, B. P. et al., 2016. GW150914: the advanced LIGO detectors in the era of first discoveries. Physical Review Letters 116 (13) 131103. (10.1103/PhysRevLett.116.131103)
- Abbott, B. P. et al., 2016. Observation of gravitational waves from a binary black hole merger. Physical Review Letters 116 (6) 061102. (10.1103/PhysRevLett.116.061102)
- Abbott, B. P. et al., 2020. Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA. Living Reviews in Relativity 23 (1) 3. (10.1007/s41114-020-00026-9)
- Abbott, R. et al., 2021. All-sky search for short gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run. Physical Review D 104 122004. (10.1103/PhysRevD.104.122004)
- Abbott, R. et al., 2022. Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO-Virgo Run O3b. Astrophysical Journal 928 (2) 186. (10.3847/1538-4357/ac532b)
- Abbott, R. et al., 2022. Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo. Astronomy & Astrophysics 659 A84. (10.1051/0004-6361/202141452)
- Abbott, R. et al., 2022. Constraints on dark photon dark matter using data from LIGO's and Virgo's third observing run. Physical Review D 105 (6) 063030. (10.1103/PhysRevD.105.063030)
- Abbott, R. et al., 2023. Constraints on the cosmic expansion history from GWTC–3. Astrophysical Journal 949 (2) 76. (10.3847/1538-4357/ac74bb)
- Abbott, R. et al., 2022. Model-based cross-correlation search for gravitational waves from the low-mass x-ray binary scorpius x-1 in ligo o3 data. Astrophysical Journal Letters 941 (2) L30. (10.3847/2041-8213/aca1b0)
- Abbott, R. et al., 2023. Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO. Astrophysical Journal Supplement 267 (2) 29. (10.3847/1538-4365/acdc9f)
- Abbott, R. et al., 2024. Search for gravitational-lensing signatures in the full third observing run of the LIGO–Virgo network. Astrophysical Journal 970 (191)(10.3847/1538-4357/ad3e83)
- Abbott, R. et al., 2024. Search for gravitational-wave transients associated with magnetar bursts in Advanced LIGO and Advanced Virgo data from the third observing run. The Astrophysical Journal 966 (1) 137. (10.3847/1538-4357/ad27d3)
- Abbott, R. et al., 2022. Searches for gravitational waves from known pulsars at two harmonics in the second and third LIGO-Virgo observing runs. Astrophysical Journal 935 (1) 1. (10.3847/1538-4357/ac6acf)
- Abe, H. et al., 2022. Performance of the KAGRA detector during the first joint observation with GEO 600 (O3GK). Progress of Theoretical and Experimental Physics ptac093. (10.1093/ptep/ptac093)
- Abe, H. et al., 2023. Noise subtraction from KAGRA O3GK data using Independent Component Analysis. Classical and Quantum Gravity 40 (8) 085015. (10.1088/1361-6382/acc0cb)
- Abe, H. et al., 2022. The current status and future prospects of KAGRA, the large-scale cryogenic gravitational wave telescope built in the Kamioka underground. Galaxies 10 (3) 63. (10.3390/galaxies10030063)
- Aiello, L. et al. 2025. Swift-BAT GUANO follow-up of gravitational-wave triggers in the Third LIGO–Virgo–KAGRA observing run. The Astrophysical Journal 980 (2) 207. (10.3847/1538-4357/ad9749)
- Aiello, L. et al., 2025. Tests of general relativity with GWTC-3. Physical Review D 112 084080. (10.1103/PhysRevD.112.084080)
- Akiyama, Y. et al., 2019. Vibration isolation system with a compact damping system for power recycling mirrors of KAGRA. Classical and Quantum Gravity 36 (9) 095015. (10.1088/1361-6382/ab0fcb)
- Akutsu, T. et al., 2025. Identification of noise-associated glitches in KAGRA O3GK with hierarchical veto. Progress of Theoretical and Experimental Physics 2025 (8) 083F01. (10.1093/ptep/ptaf093)
- Akutsu, T. et al., 2020. An arm length stabilization system for KAGRA and future gravitational-wave detectors. Classical and Quantum Gravity 37 (3) 035004. (10.1088/1361-6382/ab5c95)
- Akutsu, T. et al., 2023. Input optics systems of the KAGRA detector during O3GK. Progress of Theoretical and Experimental Physics 2023 (2) 023F01. (10.1093/ptep/ptac166)
- Akutsu, T. et al., 2021. Overview of KAGRA: Calibration, detector characterization, physical environmental monitors, and the geophysics interferometer. Progress of Theoretical and Experimental Physics 2021 (5) 05A102. (10.1093/ptep/ptab018)
- Akutsu, T. et al., 2021. Overview of KAGRA: Detector design and construction history. Progress of Theoretical and Experimental Physics 2021 (5) 05A101. (10.1093/ptep/ptaa125)
- Akutsu, T. et al., 2021. Overview of KAGRA: KAGRA science. Progress of Theoretical and Experimental Physics 2021 (5) 05A103. (10.1093/ptep/ptaa120)
- Akutsu, T. et al., 2021. Radiative cooling of the thermally isolated system in KAGRA gravitational wave telescope. Journal of Physics: Conference Series 1857 (1) 012002. (10.1088/1742-6596/1857/1/012002)
- Akutsu, T. et al., 2018. Construction of KAGRA: an underground gravitational-wave observatory. Progress of Theoretical and Experimental Physics 2018 (1) 013F01. (10.1093/ptep/ptx180)
- Al-Shammari, S. et al. 2025. GW241011 and GW241110: Exploring binary formation and fundamental physics with asymmetric, high-spin black hole coalescences. The Astrophysical Journal Letters 993 L21. (10.3847/2041-8213/ae0d54)
- Al-Shammari, S. et al. 2025. GW231123: A binary black hole merger with total mass 190–265 M⊙. The Astrophysical Journal Letters 993 (1) L25. (10.3847/2041-8213/ae0c9c)
- al-Shammari, S. et al. 2025. All-sky search for short gravitational-wave bursts in the first part of the fourth LIGO-Virgo-KAGRA observing run. Physical Review D 112 102005. (10.1103/wjdz-jdby)
- Al-Shammari, S. et al. 2025. GWTC-4.0: An introduction to version 4.0 of the Gravitational-Wave Transient Catalog. The Astrophysical Journal Letters 995 (1) L18. (10.3847/2041-8213/ae0c06)
- Amarasinghege, O. et al. 2025. GW250114: Testing Hawking’s area law and the Kerr nature of black holes. Physical Review Letters 135 111403. (10.1103/kw5g-d732)
- Bond, C. et al., 2011. Higher order Laguerre-Gauss mode degeneracy in realistic, high finesse cavities. Physical Review D - Particles, Fields, Gravitation and Cosmology 84 (10) 102002. (10.1103/PhysRevD.84.102002)
- Chen, Y. et al., 2006. Interferometers for displacement-noise-free gravitational-wave detection. Physical Review Letters 97 (15) 151103. (10.1103/PhysRevLett.97.151103)
- Evans, M. et al., 2015. Observation of Parametric Instability in Advanced LIGO. Physical Review Letters 114 (16) 161102. (10.1103/PhysRevLett.114.161102)
- Fairhurst, S. et al. 2022. All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data. Physical Review D 106 (10)(10.1103/PhysRevD.106.102008)
- Fletcher, C. et al., 2024. A joint Fermi-GBM and Swift-BAT analysis of Gravitational-wave candidates from the third Gravitational-wave Observing Run. The Astrophysical Journal 964 (2) 149. (10.3847/1538-4357/ad1eed)
- Fulda, P. et al., 2010. Experimental demonstration of higher-order Laguerre-Gauss mode interferometry. Physical Review D - Particles, Fields, Gravitation and Cosmology 82 (1) 012002. (10.1103/PhysRevD.82.012002)
- Iwaguchi, S. et al., 2025. Proof-of-principle experiment on a displacement-noise-free neutron interferometer for gravitational wave detection. Physical Review D (particles, fields, gravitation, and cosmology) 112 102002. (10.1103/yg4l-cj1t)
- KAGRA collaboration, and Kokeyama, K. 2019. KAGRA: 2.5 generation interferometric gravitational wave detector. Nature Astronomy 3 (1), pp.35-40. (10.1038/s41550-018-0658-y)
- Kawamura, S. et al., 2021. Current status of space gravitational wave antenna DECIGO and B-DECIGO. Progress of Theoretical and Experimental Physics 2021 (5) 05A105. (10.1093/ptep/ptab019)
- Kawazoe, F. et al., 2006. The experimental plan of the 4m resonant sideband extraction prototype for the LCGT. Journal of Physics: Conference Series 32 , pp.380-385. 058. (10.1088/1742-6596/32/1/058)
- Kokeyama, K. et al. 2006. Downselect of the signal extraction scheme for LCGT. Journal of Physics: Conference Series 32 065. (10.1088/1742-6596/32/1/065)
- Kokeyama, K. et al. 2008. Development of a signal-extraction scheme for resonant sideband extraction. Classical and Quantum Gravity 25 (23) 235013. (10.1088/0264-9381/25/23/235013)
- Kokeyama, K. et al. 2014. Residual amplitude modulation in interferometric gravitational wave detectors. Journal of the Optical Society of America A 31 (1), pp.81-88. (10.1364/JOSAA.31.000081)
- Kokeyama, K. et al. 2018. Demonstration for a two-axis interferometric tilt sensor in KAGRA. Physics Letters A 382 (29), pp.1950-1955. (10.1016/j.physleta.2018.05.004)
- Kokeyama, K. et al. 2009. Development of a displacement- and frequency-noise-free interferometer in a 3D configuration for gravitational wave detection. Physical Review Letters 103 171101. (10.1103/PhysRevLett.103.171101)
- Lodhia, D. et al., 2013. Interferometer phase noise due to beam misalignment on diffraction gratings. Optics Express 21 (24), pp.29578-29591. (10.1364/OE.21.029578)
- Mueller, C. L. et al., 2016. The advanced LIGO input optics. Review of Scientific Instruments 87 (1) 014502. (10.1063/1.4936974)
- Patra, A. et al. 2025. Broadband limits on stochastic length fluctuations from a pair of table-top interferometers. Physical Review Letters 135 101402. (10.1103/61j9-cjkk)
- Sakai, Y. et al., 2024. Training process of unsupervised learning architecture for gravity spy dataset. Annalen der Physik 536 (2) 2200140. (10.1002/andp.202200140)
- Sakai, Y. et al., 2022. Unsupervised learning architecture for classifying the transient noise of interferometric gravitational-wave detectors. Scientific Reports 12 (1) 9935. (10.1038/s41598-022-13329-4)
- Sato, S. et al., 2008. Demonstration of displacement-noise-free interferometry using bi-directional Mach-Zehnder interferometers. Classical and Quantum Gravity 25 (11) 114031. (10.1088/0264-9381/25/11/114031)
- Sato, S. et al., 2007. Diagonalization of the length sensing matrix of a dual recycled laser interferometer gravitational wave antenna. Physical Review D - Particles, Fields, Gravitation and Cosmology 75 (8) 082004. (10.1103/PhysRevD.75.082004)
- Sato, S. et al., 2006. Diagonalizing sensing matrix of broadband RSE. Journal of Physics: Conference Series 32 , pp.470-475. 072. (10.1088/1742-6596/32/1/072)
- Sato, S. et al., 2007. Demonstration of displacement- and frequency-noise-free laser interferometry using bidirectional Mach-Zehnder Interferometers. Physical Review Letters 98 (14) 141101. (10.1103/PhysRevLett.98.141101)
- Somiya, K. , Kokeyama, K. and Nawrodt, R. 2010. Remarks on thermoelastic effects at low temperatures and quantum limits in displacement measurements. Physical Review D, Particles and fields 63 (8) 127101. (10.1103/PHYSREVD.82.127101)
- Staley, A. et al., 2014. Achieving resonance in the advanced LIGO gravitational-wave interferometer. Classical and Quantum Gravity 31 (24) 245010. (10.1088/0264-9381/31/24/245010)
- Tanioka, S. , Pearce, T. and Kokeyama, K. 2025. Development of a polarimetry method toward in situ substrate birefringence characterization of ground-based gravitational wave detectors. Review of Scientific Instruments 96 (7) 074503. (10.1063/5.0279006)
- Wang, H. et al., 2024. Characterization of birefringence inhomogeneity of KAGRA sapphire mirrors from transmitted wavefront error measurements. Physical Review D (particles, fields, gravitation, and cosmology) 110 (8) 082007. (10.1103/physrevd.110.082007)
- Yamada, R. et al., 2020. Optimization of quantum noise by completing the square of multiple interferometer outputs in quantum locking for gravitational wave detectors. Physics Letters A 384 (26) 126626. (10.1016/j.physleta.2020.126626)
- Yamamoto, K. et al., 2019. Design and experimental demonstration of a laser modulation system for future gravitational-wave detectors. Classical and Quantum Gravity 36 (20) 205009. (10.1088/1361-6382/ab4489)
- Zhu, Z. -. et al., 2020. Application of independent component analysis to the iKAGRA data. Progress of Theoretical and Experimental Physics 2020 (5) 053F01. (10.1093/ptep/ptaa056)
Conferences
- Fulda, P. et al., 2012. Review of the Laguerre-Gauss mode technology research program at Birmingham. Presented at: 9th Edoardo Amaldi Conference and Numerical Relativity - Data Analysis Meeting (Amaldi 9/NRDA 2011) Cardiff, Wales 10-15 July 2011. Vol. 363.IOP Publishing: Conference Series. , pp.012010. (10.1088/1742-6596/363/1/012010)
- Kokeyama, K. et al. 2008. The experimental plan of displacement- and frequency-noise free laser interferometer. Presented at: The Seventh Edoardo Amaldi Conference On Gravitational Waves (amaldi7) Sydney, Australia 8-14 July 2007. Vol. 122.IOP Publishing: Conference Series. (10.1088/1742-6596/122/1/012022)
Research
My research interests fall within the field of detector science for gravitational wave astrophysics.
-
Development of a novel birefringence sensor
-
Advanced sensing and control modeling for thermally affected interferometers
-
Implementation of variable reflectivity mirrors based on the etalon effect
-
Exploration of alternative thermal compensation systems for next-generation gravitational-wave detectors
For more information, visit our experimental group's website: https://exp.gravity.cf.ac.uk/
Teaching
Join my gravitational-wave classes and projects!
2024-25
- Techniques in Precision Measurement (PXT906)
- Experimental Physics (PXT1150)
- MSC Physics Project (PXT999)
2021-22, 2022-23, 2023-24
- Experimental Gravitational-Wave Physics II (PXT902)
- Experimental Physics (PXT1150)
- Physics Project (PXT3315 and 3350)
- MSC Physics Project (PXT999)
2021-22
- Experimental Gravitational-Wave Physics II (PXT902)
Biography
Professional memberships
- LIGO Scientific Collaboration (2009 - 2014, 2021 - Current)
- KAGRA Collaboration (2015 - Current)
- Gravity Allies (2024 - Current)
- KAGRA Scientific Congress Board (2021 - 2023)
Academic positions
- 2024 - Current: Associate Professor, Nagoya University, Japan (50% cross-appointment with Cardiff University).
- 2024 - Current: Senior Lecturer, Cardiff University, UK.
- 2021 - 2023: Lecturer, Cardiff University, UK.
- 2017 - 2021: Assistant Professor, Institute for Cosmic Ray Research, The University of Tokyo, Japan
- 2015 - 2017: Project Assistant Professor, Institute for Cosmic Ray Research, The University of Tokyo, Japan
- 2011 - 2015: Postdoctoral researcher, Louisiana State University, US.
- 2009 - 2011: Postdoctoral researcher, University of Birmingham, UK.
Contact Details
[email protected]
+44 29225 14051
Queen's Buildings, Floor 2, Room N/2.13, 5 The Parade, Newport Road, Cardiff, CF24 3AA
+44 29225 14051
Queen's Buildings, Floor 2, Room N/2.13, 5 The Parade, Newport Road, Cardiff, CF24 3AA
