Discrete Time-Crystalline Order in Cavity and Circuit QED Systems.
- Z. Gong, Ryusuke Hamazaki, Masahito Ueda
- PhysicsPhysical Review Letters
- 4 August 2017
A phenomenology of dissipative discrete time crystals is established by generalizing the Landau theory of phase transitions to Floquet open systems and finding clear signatures of a transient discrete time-crystalline behavior, which is absent in the isolated counterpart.
Magnetic Solitons in a Spin-1 Bose-Einstein Condensate.
- Xiao Chai, Di Lao, K. Fujimoto, Ryusuke Hamazaki, Masahito Ueda, C. Raman
- PhysicsPhysical Review Letters
- 13 December 2019
Here, using a "magnetic shadowing" technique, a new type of soliton in a spinor Bose-Einstein condensate is observed, one that exists only when the underlying interactions are antiferromagnetic and which is deeply embedded within a full spin-1 quantum system.
Constructing neural stationary states for open quantum many-body systems
- N. Yoshioka, Ryusuke Hamazaki
- PhysicsPhysical review B
- 19 February 2019
A new variational scheme based on the neural-network quantum states to simulate the stationary states of open quantum many-body systems, which is dubbed as the neural stationary state ansatz, and shown to simulate various spin systems efficiently.
Universality classes of non-Hermitian random matrices
- Ryusuke Hamazaki, K. Kawabata, N. Kura, Masahito Ueda
- Physics
- 30 April 2019
Non-Hermitian random matrices have been utilized in such diverse fields as dissipative and stochastic processes, mesoscopic physics, nuclear physics, and neural networks. However, the only known…
Non-Hermitian Many-Body Localization.
- Ryusuke Hamazaki, K. Kawabata, Masahito Ueda
- PhysicsPhysical Review Letters
- 28 November 2018
It is demonstrated that a real-complex transition profoundly affects the dynamical stability of non-Hermitian interacting systems with asymmetric hopping that respects time-reversal symmetry.
Eigenstate Thermalization in Long-Range Interacting Systems.
- Shoki Sugimoto, Ryusuke Hamazaki, M. Ueda
- PhysicsPhysical Review Letters
- 24 November 2021
Motivated by recent ion experiments on tunable long-range interacting quantum systems [Neyenhuis et al., Sci. Adv. 3, e1700672 (2017)SACDAF2375-254810.1126/sciadv.1700672], we test the strong…
Atypicality of Most Few-Body Observables.
- Ryusuke Hamazaki, Masahito Ueda
- PhysicsPhysical Review Letters
- 16 August 2017
It is shown that the typicality argument does not apply to most few- body observables for few-body Hamiltonians when the width of the energy shell decreases at most polynomially with increasing the size of the system.
Liouvillian Skin Effect: Slowing Down of Relaxation Processes without Gap Closing.
- T. Haga, Masaya Nakagawa, Ryusuke Hamazaki, Masahito Ueda
- PhysicsPhysical Review Letters
- 2 May 2020
The relaxation processes of a quantum dissipative system that exhibits the Liouvillian skin effect is investigated, and it is shown that the longest relaxation time τ that is maximized over initial states and local observables is given by τ∼Δ^{-1}(1+L/ξ) with L being the system size.
Test of the Eigenstate Thermalization Hypothesis Based on Local Random Matrix Theory.
- Shoki Sugimoto, Ryusuke Hamazaki, Masahito Ueda
- PhysicsPhysical Review Letters
- 13 May 2020
It is verified that the eigenstate thermalization hypothesis (ETH) holds universally for locally interacting quantum many-body systems and an overwhelming majority of pairs of local Hamiltonians and observables satisfy the ETH with exponentially small fluctuations.
Bounds in nonequilibrium quantum dynamics
- Z. Gong, Ryusuke Hamazaki
- PhysicsInternational Journal of Modern Physics B
- 4 February 2022
We review various bounds concerning out-of-equilibrium dynamics in few-level and many-body quantum systems. We primarily focus on closed quantum systems but will also mention some related results for…
...
...