67 citations · 313 across the 21 of their papers we have counts for
21 papers
Quantum uncertainty of gravitational field and entanglement in superposed massive particles
Yuuki Sugiyama, Akira Matsumura, Kazuhiro Yamamoto
Investigating the quantum nature of gravity is an important issue in modern physics. Recently, studies pertaining to the quantum superposition of gravitational potential have garne…
Enhancement of quantum gravity signal in an optomechanical experiment
Youka Kaku, Tomohiro Fujita, Akira Matsumura
No experimental evidence of the quantum nature of gravity has been observed yet and a realistic setup with improved sensitivity is eagerly awaited. We find two effects, which can s…
Quantum state of a suspended mirror coupled to cavity light -- Wiener filter analysis of the pendulum and rotational modes
Tomoya Shichijo, Nobuyuki Matsumoto, Akira Matsumura +3
We investigated the quantum state of an optomechanical suspended mirror under continuous measurement and feedback control using Wiener filtering. We focus on the impact of the two-…
Reduced dynamics with Poincaré symmetry in an open quantum system
Akira Matsumura
We consider how the reduced dynamics of an open quantum system coupled to an environment admits the Poincaré symmetry. The reduced dynamics is described by a dynamical map, which i…
Effective description of a suspended mirror coupled to cavity light -Limitations of Q-enhancement due to normal mode splitting by an optical spring-
Yuuki Sugiyama, Tomoya Shichijo, Nobuyuki Matsumoto +3
Pendulums have long been used as force sensors due to their ultimately low dissipation (high-quality factor) characteristic. They are widely used in the measurement of the gravitat…
Generating quantum entanglement between macroscopic objects with continuous measurement and feedback control
Daisuke Miki, Nobuyuki Matsumoto, Akira Matsumura +4
This study is aimed at investigating the feasibility of generating quantum entanglement between macroscopic mechanical mirrors in optomechanical systems while under continuous meas…
Consistency between causality and complementarity guaranteed by the Robertson inequality in quantum field theory
Yuuki Sugiyama, Akira Matsumura, Kazuhiro Yamamoto
It has long been debated whether gravity should be quantized or not. Recently, the authors in [Sci. Rep. 6, 22777 (2016); Proc. Natl. Acad. Sci. U.S.A. 106, 3035 (2009)] discussed…
Role of matter coherence in entanglement due to gravity
Akira Matsumura
We investigate the quantum nature of gravity in terms of the coherence of quantum objects. As a basic setting, we consider two gravitating objects each in a superposition state of…
Effects of photon field on entanglement generation in charged particles
Yuuki Sugiyama, Akira Matsumura, Kazuhiro Yamamoto
The Bose-Marletto-Vedral (BMV) experiment [3, 4] is a proposal for testing the quantum nature of gravity with entanglement due to Newtonian gravity. This proposal has stimulated co…
Path-entangling evolution and quantum gravitational interaction
Akira Matsumura
We explore a general feature of the interaction mediated by the gravitational fields of spatially superposed masses. For this purpose, based on quantum information theory, we chara…
Leggett-Garg inequalities for testing quantumness of gravity
Akira Matsumura, Yasusada Nambu, Kazuhiro Yamamoto
In this study, we determine a violation of the Leggett-Garg inequalities due to gravitational interaction in a hybrid system consisting of a harmonic oscillator and a spatially loc…
Non-Gaussian entanglement in gravitating masses: the role of cumulants
Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto
We develop an entanglement criterion with third- and fourth-order cumulants to detect the entanglement of non-Gaussian states. The efficiency of the entanglement criterion is inves…
Harvesting quantum coherence from axion dark matter
Sugumi Kanno, Akira Matsumura, Jiro Soda
Quantum coherence is one of the most striking features of quantum mechanics rooted in the superposition principle. Recently it has been demonstrated that it is possible to harvest…
Field-induced entanglement in spatially superposed objects
Akira Matsumura
We discuss the generation of field-induced entanglement between two objects each in a superposition of two trajectories.The objects have currents coupled to local quantum fields, a…
Gravity-induced entanglement in optomechanical systems
Akira Matsumura, Kazuhiro Yamamoto
We investigate the phenomenon of gravity-induced entanglement in optomechanical systems. Assuming photon number conservation and the Newtonian potential expanded up to the quadrati…
Entanglement and decoherence of massive particles due to gravity
Daisuke Miki, Akira Matsumura, Kazuhiro Yamamoto
We analyze the dynamics of a gravity-induced entanglement for N massive particles. Considering the linear configuration of these particles, we investigate the entanglement between…
Squeezing of primordial gravitational waves as quantum discord
Akira Matsumura, Yasusada Nambu
We investigate the squeezing of primordial gravitational waves (PGWs) in terms of quantum discord. We construct a classical state of PGWs without quantum discord and compare it wit…
Violation of Bell-CHSH inequalities through optimal local filters in the vacuum
Akira Matsumura, Yasusada Nambu
We investigate quantum correlations appearing for two qubit detectors which are initially uncorrelated and locally coupled to a massless scalar field in a vacuum state. Under the p…
Quantum Circuit Model of Black Hole Evaporation
Tomoro Tokusumi, Akira Matsumura, Yasusada Nambu
We consider a quantum circuit model describing the evaporation process of black holes. We specifically examine the behavior of the multipartite entanglement represented by this mod…
Parameter estimation by decoherence in the double-slit experiment
Akira Matsumura, Taishi Ikeda, Shingo Kukita
We discuss a parameter estimation problem using quantum decoherece in the double-slit interferometer. We consider a particle coupled to a massive scalar field after the particle pa…
Large scale quantum entanglement in de Sitter spacetime
Akira Matsumura, Yasusada Nambu
We investigate quantum entanglement between two symmetric spatialregions in de Sitter space with the Bunch-Davies vacuum. As a discretized model of the scalar field for numerical s…