12 citations · 34 across the 12 of their papers we have counts for
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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…
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…
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…
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…
Feasible generation of gravity-induced entanglement by using optomechanical systems
Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto
We report the feasibility of detecting the gravity-induced entanglement (GIE) with optomechanical systems, which is the first investigation that clarifies the feasible experimental…
Large violation of Leggett-Garg inequalities with coherent-state projectors for a harmonic oscillator and chiral scalar field
Tomoya Hirotani, Akira Matsumura, Yasusada Nambu +1
We investigate violations of Leggett-Garg inequalities (LGIs) for a harmonic oscillator and a (1+1)-dimensional chiral scalar field with coherent-state projectors, which is equival…
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…
Negativity volume of the generalized Wigner function in gravitating hybrid system
Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto
We evaluate the gravity-induced negativity volume of the generalized Wigner function in a hybrid system consisting of a particle in a two-localized superposition state and an oscil…
Violation of the two-time Leggett-Garg inequalities for a coarse-grained quantum field
Masaki Tani, Kosei Hatakeyama, Daisuke Miki +2
We investigate the violation of the Leggett-Garg inequalities for a quantum field, focusing on the two-time quasi-probability distribution function of the dichotomic variable with…
Violation of the two-time Leggett-Garg inequalities for a harmonic oscillator
Kosei Hatakeyama, Daisuke Miki, Masaki Tani +5
We investigate the violation of the Leggett-Garg inequalities for a harmonic oscillator in various quantum states. We focus on the two-time quasi-probability distribution function…