7 papers
Measurement-Based Estimation of Causal Conditional Variances and Its Application to Macroscopic quantum phenomenon
Kosei Hatakeyama, Ryotaro Fukuzumi, Akira Matsumura +2
We analytically investigate a quantum estimation method for a mechanical oscillator in a detuned cavity system based solely on homodyne measurement records, building on the framewo…
Theoretical Study of the Squeezed-Light-Enhanced Sensitivity to Gravity-Induced Entanglement via Finite-Time Analysis
Kosei Hatakeyama, Daisuke Miki, Kazuhiro Yamamoto
We investigate the advantage of using squeezed input light for generating gravity-induced entanglement (GIE) through Fourier-domain analysis. Based on the findings of Ref.~\cite{Mi…
Momentum Squeezed State Realized via Optimal Filtering in Optomechanics: Implications for Gravity-Induced Entanglement
Ryotaro Fukuzumi, Kosei Hatakeyama, Daisuke Miki +1
We analyze the conditional quantum state of a mechanical mirror in an optomechanical system subject to continuous measurement, feedback control, and quantum filtering. We identify…
Space-based cm/kg-scale Laser Interferometer for Quantum Gravity
Nobuyuki Matsumoto, Katsuta Sakai, Kosei Hatakeyama +5
The experimental verification of the quantum nature of gravity represents a milestone in quantum gravity research. Recently, interest has grown for testing it via gravitationally i…
Decoherence of spin superposition state caused by a quantum electromagnetic field
Kensuke Gallock-Yoshimura, Yuuki Sugiyama, Akira Matsumura +1
In this study, we investigate the decoherence of a spatially superposed electrically neutral spin- particle in the presence of a relativistic quantum electromagnetic field…
Quantumness of gravitational field: A perspective on monogamy relation
Yuuki Sugiyama, Akira Matsumura, Kazuhiro Yamamoto
Understanding the phenomenon of quantum superposition of gravitational fields induced by massive quantum particles is an important starting point for quantum gravity. The purpose o…