All Stories

  1. Gauge-Invariant Perturbation Theory on the Schwarzschild Background Spacetime: Part III—Realization of Exact Solutions

    Article • Universe, February 2025, MDPI AG

    Dr. Kouji Nakamura

  2. Gauge-Invariant Perturbation Theory on the Schwarzschild Background Spacetime Part II: Even-Mode Perturbations

    Article • Universe, January 2025, MDPI AG

    Dr. Kouji Nakamura

  3. Gauge-Invariant Perturbation Theory on the Schwarzschild Background Spacetime Part I: Formulation and Odd-Mode Perturbations

    Article • Universe, January 2025, MDPI AG

    Dr. Kouji Nakamura

  4. Comparing a Gauge-Invariant Formulation and a “Conventional Complete Gauge-Fixing Approach” for l=0,1-Mode Perturbations on the Schwarzschild Background Spacetime

    Article • Universe, November 2024, MDPI AG

    Dr. Kouji Nakamura

  5. Gauge-Invariant Perturbation Theory on the Schwarzschild Background Spacetime Part II: — Even-Mode Perturbations —

    Article • October 2024, MDPI AG

    Dr. Kouji Nakamura

  6. Comparing a Gauge-Invariant Formulation and a “Conventional Complete Gauge-Fixing Approach” for l = 0, 1 Mode Perturbations on the Schwarzschild Background Spacetime

    Article • September 2024, MDPI AG

    Dr. Kouji Nakamura

  7. Constraints on the Cosmic Expansion History from GWTC–3

    Article • The Astrophysical Journal, June 2023, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  8. Population of Merging Compact Binaries Inferred Using Gravitational Waves through GWTC-3

    Article • Physical Review X, March 2023, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  9. Input optics systems of the KAGRA detector during O3GK

    Article • Progress of Theoretical and Experimental Physics, December 2022, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  10. Model-based Cross-correlation Search for Gravitational Waves from the Low-mass X-Ray Binary Scorpius X-1 in LIGO O3 Data

    Article • The Astrophysical Journal Letters, December 2022, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  11. All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data

    Article • November 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  12. Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

    Article • September 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  13. Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO-Virgo data

    Article • August 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  14. Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO’s and Advanced Virgo’s Third Observing Run

    Article • Physical Review Letters, August 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  15. All-sky, all-frequency directional search for persistent gravitational waves from Advanced LIGO’s and Advanced Virgo’s first three observing runs

    Article • June 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  16. Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

    Article • The Astrophysical Journal, June 2022, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  17. Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

    Article • The Astrophysical Journal, May 2022, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  18. All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data

    Article • May 2022, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  19. First joint observation by the underground gravitational-wave detector KAGRA with GEO 600

    Article • Progress of Theoretical and Experimental Physics, April 2022, Oxford University Press (OUP)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  20. The Current Status and Future Prospects of KAGRA, the Large-Scale Cryogenic Gravitational Wave Telescope Built in the Kamioka Underground

    Article • Galaxies, April 2022, MDPI AG

    Dr. Kouji Nakamura

  21. Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO–Virgo Run O3b

    Article • The Astrophysical Journal, April 2022, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  22. Constraints on dark photon dark matter using data from LIGO’s and Virgo’s third observing run

    Article • March 2022, American Physical Society (APS)

    Dr Aldo Ejlli, Dr. Kouji Nakamura

  23. Search for intermediate-mass black hole binaries in the third observing run of Advanced LIGO and Advanced Virgo

    Article • EAS Publications Series, March 2022, EDP Sciences

    Dr Aldo Ejlli, Dr. Kouji Nakamura

  24. Search for continuous gravitational waves from 20 accreting millisecond x-ray pulsars in O3 LIGO data

    Article • January 2022, American Physical Society (APS)

    Dr Aldo Ejlli, Dr. Kouji Nakamura

  25. All-sky search for short gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run

    Article • December 2021, American Physical Society (APS)

    Dr Aldo Ejlli, Dr. Kouji Nakamura

  26. All-sky search for long-duration gravitational-wave bursts in the third Advanced LIGO and Advanced Virgo run

    Article • November 2021, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  27. Searches for Continuous Gravitational Waves from Young Supernova Remnants in the Early Third Observing Run of Advanced LIGO and Virgo

    Article • The Astrophysical Journal, November 2021, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  28. Constraints from LIGO O3 Data on Gravitational-wave Emission Due to R-modes in the Glitching Pulsar PSR J0537–6910

    Article • The Astrophysical Journal, November 2021, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  29. All-sky search for continuous gravitational waves from isolated neutron stars in the early O3 LIGO data

    Article • October 2021, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  30. Quantum noise and vacuum fluctuations in balanced homodyne detections through ideal multi-mode detectors

    Article • Progress of Theoretical and Experimental Physics, September 2021, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  31. Search for anisotropic gravitational-wave backgrounds using data from Advanced LIGO and Advanced Virgo’s first three observing runs

    Article • July 2021, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  32. Upper limits on the isotropic gravitational-wave background from Advanced LIGO and Advanced Virgo’s third observing run

    Article • July 2021, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  33. Observation of Gravitational Waves from Two Neutron Star–Black Hole Coalescences

    Article • The Astrophysical Journal Letters, June 2021, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli, Dr. Guillermo Valdes

  34. Constraints on Cosmic Strings Using Data from the Third Advanced LIGO–Virgo Observing Run

    Article • Physical Review Letters, June 2021, American Physical Society (APS)

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  35. Proposal of a gauge-invariant treatment of l = 0, 1-mode perturbations on Schwarzschild background spacetime

    Article • Classical and Quantum Gravity, June 2021, Institute of Physics Publishing

    Dr. Kouji Nakamura

  36. Diving below the Spin-down Limit: Constraints on Gravitational Waves from the Energetic Young Pulsar PSR J0537-6910

    Article • The Astrophysical Journal Letters, May 2021, American Astronomical Society

    Dr. Kouji Nakamura, Dr Aldo Ejlli

  37. Radiative Cooling of the Thermally Isolated System in KAGRA Gravitational Wave Telescope

    Article • Journal of Physics Conference Series, April 2021, Institute of Physics Publishing

    Dr. Kouji Nakamura

  38. Vibration isolation systems for the beam splitter and signal recycling mirrors of the KAGRA gravitational wave detector

    Article • Classical and Quantum Gravity, March 2021, Institute of Physics Publishing

    Dr. Kouji Nakamura

  39. Current status of space gravitational wave antenna DECIGO and B-DECIGO

    Article • Progress of Theoretical and Experimental Physics, February 2021, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  40. Overview of KAGRA: Calibration, detector characterization, physical environmental monitors, and the geophysics interferometer

    Article • Progress of Theoretical and Experimental Physics, February 2021, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  41. Formal Solutions of Any-Order Mass, Angular-Momentum, andDipole Perturbations on the Schwarzschild Background Spacetime

    Article • Letters in High Energy Physics, January 2021, Andromeda Publishing and Education Services

    Dr. Kouji Nakamura

  42. Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

    Article • Living Reviews in Relativity, September 2020, Springer Science + Business Media

    Dr. Kouji Nakamura

  43. Overview of KAGRA: Detector design and construction history

    Article • Progress of Theoretical and Experimental Physics, August 2020, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  44. Overview of KAGRA: KAGRA science

    Article • Progress of Theoretical and Experimental Physics, August 2020, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  45. Application of independent component analysis to the iKAGRA data

    Article • Progress of Theoretical and Experimental Physics, May 2020, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  46. Theory and Applications of Physical Science Vol. 3

    Article • February 2020, Sciencedomain International

    Dr. Kouji Nakamura

  47. An arm length stabilization system for KAGRA and future gravitational-wave detectors

    Article • Classical and Quantum Gravity, January 2020, Institute of Physics Publishing

    Dr. Kouji Nakamura

  48. The status of KAGRA underground cryogenic gravitational wave telescope

    Article • Journal of Physics Conference Series, January 2020, Institute of Physics Publishing

    Dr. Kouji Nakamura

  49. Space gravitational-wave antennas DECIGO and B-DECIGO

    Article • International Journal of Modern Physics D, September 2019, World Scientific Pub Co Pte Lt

    Dr. Kouji Nakamura

  50. First cryogenic test operation of underground km-scale gravitational-wave observatory KAGRA

    Article • Classical and Quantum Gravity, July 2019, Institute of Physics Publishing

    Dr. Kouji Nakamura

  51. Vibration isolation system with a compact damping system for power recycling mirrors of KAGRA

    Article • Classical and Quantum Gravity, April 2019, Institute of Physics Publishing

    Dr. Kouji Nakamura

  52. KAGRA: 2.5 generation interferometric gravitational wave detector

    Article • Nature Astronomy, January 2019, Springer Science + Business Media

    Dr. Kouji Nakamura

  53. Extension of the input–output relation for a Michelson interferometer to arbitrary coherent-state light sources: Gravitational-wave detector and weak-value amplification

    Article • Annals of Physics, May 2018, Elsevier

    Dr. Kouji Nakamura

  54. Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

    Article • Living Reviews in Relativity, April 2018, Springer Science + Business Media

    Professor László Árpád Gergely, Dr. Kouji Nakamura

  55. Construction of KAGRA: an underground gravitational-wave observatory

    Article • Progress of Theoretical and Experimental Physics, January 2018, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  56. The status of DECIGO

    Article • Journal of Physics Conference Series, May 2017, Institute of Physics Publishing

    Dr. Kouji Nakamura

  57. CONSTRUCTION OF GAUGE-INVARIANT VARIABLES FOR LINEAR-ORDER METRIC PERTURBATIONS ON AN ARBITRARY BACKGROUND SPACETIME

    Article • January 2015, World Scientific Pub Co Pte Lt

    Dr. Kouji Nakamura

  58. Torsion-bar antenna in the proper reference frame with rotation

    Article • Physical Review D, September 2014, American Physical Society (APS)

    Dr. Kouji Nakamura

  59. Recursive structure in the definitions of gauge-invariant variables for any order perturbations

    Article • Classical and Quantum Gravity, June 2014, Institute of Physics Publishing

    Dr. Kouji Nakamura

  60. Reinterpretations of an experiment on the backaction in a weak measurement

    Article • Physical Review A, October 2013, American Physical Society (APS)

    Dr. Kouji Nakamura

  61. Construction of gauge-invariant variables of linear metric perturbations on an arbitrary background spacetime

    Article • Progress of Theoretical and Experimental Physics, April 2013, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  62. GAUGE-INVARIANT VARIABLES IN GENERAL-RELATIVISTIC PERTURBATIONS: GLOBALIZATION AND ZERO-MODE PROBLEM

    Article • International Journal of Modern Physics D, October 2012, World Scientific Pub Co Pte Lt

    Dr. Kouji Nakamura

  63. Weak-value amplification in a shot-noise-limited interferometer

    Article • Physical Review A, June 2012, American Physical Society (APS)

    Dr. Kouji Nakamura

  64. Detector configuration of KAGRA–the Japanese cryogenic gravitational-wave detector

    Article • Classical and Quantum Gravity, June 2012, Institute of Physics Publishing

    Dr. Kouji Nakamura

  65. Evaluation of weak measurements to all orders

    Article • Physical Review A, January 2012, American Physical Society (APS)

    Dr. Kouji Nakamura

  66. Comparing two different formulations of metric cosmological perturbation theory

    Article • Classical and Quantum Gravity, October 2011, Institute of Physics Publishing

    Dr. Kouji Nakamura

  67. General formulation of general-relativistic higher-order gauge-invariant perturbation theory

    Article • Classical and Quantum Gravity, May 2011, Institute of Physics Publishing

    Dr. Kouji Nakamura

  68. The Japanese space gravitational wave antenna: DECIGO

    Article • Classical and Quantum Gravity, April 2011, Institute of Physics Publishing

    Dr. Kouji Nakamura

  69. Weak Value in Wave Function of Detector

    Article • Journal of the Physical Society of Japan, December 2010, Physical Society of Japan

    Dr. Kouji Nakamura

  70. DECIGO and DECIGO pathfinder

    Article • Classical and Quantum Gravity, April 2010, Institute of Physics Publishing

    Dr. Kouji Nakamura

  71. Second‐Order Gauge‐Invariant Cosmological Perturbation Theory: Current Status

    Article • Advances in Astronomy, January 2010, Wiley

    Dr. Kouji Nakamura

  72. Perturbations of matter fields in the second-order gauge-invariant cosmological perturbation theory

    Article • Physical Review D, December 2009, American Physical Society (APS)

    Dr. Kouji Nakamura

  73. Consistency of Equations in the Second-Order Gauge- Invariant Cosmological Perturbation Theory

    Article • Progress of Theoretical Physics, June 2009, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  74. DECIGO pathfinder

    Article • Classical and Quantum Gravity, April 2009, Institute of Physics Publishing

    Dr. Kouji Nakamura

  75. DECIGO: The Japanese space gravitational wave antenna

    Article • Journal of Physics Conference Series, March 2009, Institute of Physics Publishing

    Dr. Kouji Nakamura

  76. DECIGO: THE JAPANESE SPACE GRAVITATIONAL WAVE ANTENNA

    Article • September 2008, World Scientific Pub Co Pte Lt

    Dr. Kouji Nakamura

  77. DECIGO pathfinder

    Article • Journal of Physics Conference Series, July 2008, Institute of Physics Publishing

    Dr. Kouji Nakamura

  78. The Japanese space gravitational wave antenna - DECIGO

    Article • Journal of Physics Conference Series, July 2008, Institute of Physics Publishing

    Dr. Kouji Nakamura

  79. The Japanese space gravitational wave antenna; DECIGO

    Article • Journal of Physics Conference Series, July 2008, Institute of Physics Publishing

    Dr. Kouji Nakamura

  80. Second-Order Gauge Invariant Cosmological Perturbation Theory

    Article • Progress of Theoretical Physics, January 2007, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  81. Gauge-invariant formulation of second-order cosmological perturbations

    Article • Physical Review D, November 2006, American Physical Society (APS)

    Dr. Kouji Nakamura

  82. The Japanese space gravitational wave antenna—DECIGO

    Article • Classical and Quantum Gravity, March 2006, Institute of Physics Publishing

    Dr. Kouji Nakamura

  83. Spherically symmetric spacetimes with a trapped surface

    Article • Classical and Quantum Gravity, May 2005, Institute of Physics Publishing

    Dr. Kouji Nakamura

  84. Second-Order Gauge Invariant Perturbation Theory: -- Perturbative Curvatures in the Two-Parameter Case --

    Article • Progress of Theoretical Physics, March 2005, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  85. The continuous limit of the multiple lens effect and the optical scalar equation

    Article • Monthly Notices of the Royal Astronomical Society, March 2005, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  86. Causal structure and gravitational waves in brane world cosmology

    Article • Physical Review D, September 2004, American Physical Society (APS)

    Dr. Kouji Nakamura

  87. Gauge Invariant Variables in Two-Parameter Nonlinear Perturbations

    Article • Progress of Theoretical Physics, October 2003, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  88. Comparison of the Oscillatory Behavior of a Gravitating Nambu-Goto String and a Test String

    Article • Progress of Theoretical Physics, August 2003, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  89. The hoop conjecture and cosmic censorship in the brane-world

    Article • Physics Letters B, July 2003, Elsevier

    Dr. Kouji Nakamura

  90. DYNAMICS OF A STRING COUPLED TO GRAVITATIONAL WAVES

    Article • December 2002, World Scientific Pub Co Pte Lt

    Dr. Kouji Nakamura

  91. Does a Nambu-Goto wall emit gravitational waves? Cylindrical Nambu-Goto wall as an example of gravitating nonspherical walls

    Article • Physical Review D, October 2002, American Physical Society (APS)

    Dr. Kouji Nakamura

  92. Initial condition of a gravitating thick loop cosmic string and linear perturbations

    Article • Classical and Quantum Gravity, February 2002, Institute of Physics Publishing

    Dr. Kouji Nakamura

  93. Hoop Conjecture and Black Holes on a Brane

    Article • Progress of Theoretical Physics Supplement, January 2002, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  94. Dynamics of a string coupled to gravitational waves. II. Perturbations propagate along an infinite Nambu-Goto string

    Article • Physical Review D, May 2001, American Physical Society (APS)

    Dr. Kouji Nakamura

  95. Dynamics of a string coupled to gravitational waves: Gravitational wave scattering by a Nambu-Goto straight string

    Article • Physical Review D, October 2000, American Physical Society (APS)

    Dr. Kouji Nakamura

  96. Erratum: Relativistic Zel’dovich approximation in a spherically symmetric model [Phys. Rev. D 57, 6094 (1998)]

    Article • Physical Review D, September 1998, American Physical Society (APS)

    Dr. Kouji Nakamura

  97. Relativistic Zel’dovich approximation in a spherically symmetric model

    Article • Physical Review D, May 1998, American Physical Society (APS)

    Dr. Kouji Nakamura

  98. Surface gravity in dynamical spherically symmetric spacetimes

    Article • Physical Review D, September 1996, American Physical Society (APS)

    Dr. Kouji Nakamura

  99. Critical behavior near the singularity in a scalar field collapse

    Article • Physical Review D, July 1996, American Physical Society (APS)

    Dr. Kouji Nakamura

  100. Quantum formation of black holes and wormholes in the gravitational collapse of a dust shell

    Article • Physical Review D, April 1996, American Physical Society (APS)

    Dr. Kouji Nakamura

  101. Critical Behavior of Black Hole Formation in a Scalar Wave Collapse

    Article • Progress of Theoretical Physics, June 1994, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  102. Critical Behavior of Black Hole Formation in a Scalar Wave Collapse

    Article • Progress of Theoretical Physics, June 1994, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  103. Quantum Fluctuations of Black Hole Geometry

    Article • Progress of Theoretical Physics, October 1993, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  104. Quantum Fluctuations of Black Hole Geometry

    Article • Progress of Theoretical Physics, September 1993, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  105. Evaporation of a Collapsing Shell with Scalar Field Production

    Article • Progress of Theoretical Physics, January 1993, Oxford University Press (OUP)

    Dr. Kouji Nakamura

  106. Evaporation of a Collapsing Shell with Scalar Field Production

    Article • Progress of Theoretical Physics, January 1993, Oxford University Press (OUP)

    Dr. Kouji Nakamura