Ryusuke Hamazaki
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View article: Numerical code for Optimal Work Extraction from Finite-Time Closed Quantum Dynamics
Numerical code for Optimal Work Extraction from Finite-Time Closed Quantum Dynamics Open
This repository provides the minimal source code used to generate the numerical data presented in Figures 3 and 4 of the paper: Shoki Sugimoto, Takahiro Sagawa, and Ryusuke Hamazaki, Optimal Work Extraction from Finite-Time Closed Quantum …
View article: Eigenstate Thermalization Hypothesis with Projective Representation
Eigenstate Thermalization Hypothesis with Projective Representation Open
The Eigenstate Thermalization Hypothesis (ETH) provides a sufficient condition for thermalization of isolated quantum systems. While the standard ETH is formulated in the absence of degeneracy, physical systems often possess symmetries tha…
View article: Quasiprobability Thermodynamic Uncertainty Relation
Quasiprobability Thermodynamic Uncertainty Relation Open
We derive a quantum extension of the thermodynamic uncertainty relation where dynamical fluctuations are quantified by the Terletsky-Margenau-Hill quasiprobability, a quantum generalization of the classical joint probability. The obtained …
View article: Topology and Spectrum in Measurement-Induced Phase Transitions
Topology and Spectrum in Measurement-Induced Phase Transitions Open
Competition among repetitive measurements of noncommuting observables and unitary dynamics can give rise to a wide variety of entanglement phases. Here, we characterize topological phases in monitored quantum systems by their spectrum and …
View article: Transitions of the Lyapunov spectrum and entanglement entropy in monitored quantum dynamics with homogeneous unitary gates
Transitions of the Lyapunov spectrum and entanglement entropy in monitored quantum dynamics with homogeneous unitary gates Open
We explore the Lyapunov spectrum and entanglement entropy in systems evolved by quantum measurements and spatially homogeneous unitary gates. In models with temporally random and Floquet unitary gates, we find that the Lyapunov exponents t…
View article: Dataset for "Measurement-Induced Crossover of Quantum Jump Statistics in Postselection-Free Many-Body Dynamics"
Dataset for "Measurement-Induced Crossover of Quantum Jump Statistics in Postselection-Free Many-Body Dynamics" Open
Dataset for the Python language. The "np" stands for the abbreviation for "numpy". MICJumpStatistics.zip: The folder "Variance" includes the two-dimensional array for the set [SFQJ, variance in the total system] for the measurement strengt…
View article: Speed limits to fluctuation dynamics
Speed limits to fluctuation dynamics Open
Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems, along with dynamics of the mean. While universal speed limits for the mean have actively been studied recently, constraints fo…
View article: Kinetically constrained models constructed from dissipative quantum dynamics
Kinetically constrained models constructed from dissipative quantum dynamics Open
We propose a construction of kinetically constrained models using the\nMarkovian quantum dynamics under strong dissipation. Engineering the\nGorini-Kossakowski-Sudarshan-Lindblad (GKSL) equation through classical noise,\nwe show that stron…
View article: Measurement-Induced Spectral Transition
Measurement-Induced Spectral Transition Open
We show that noisy quantum dynamics exposed to weak measurements exhibit a spectral transition between gapless and gapped phases. To this end, we employ the Lyapunov spectrum obtained through singular values of a non-unitary matrix describ…
View article: Quantum velocity limits for multiple observables: Conservation laws, correlations, and macroscopic systems
Quantum velocity limits for multiple observables: Conservation laws, correlations, and macroscopic systems Open
How multiple observables mutually influence their dynamics has been a crucial issue in statistical mechanics. We here introduce a new concept, “quantum velocity limits,” to establish a quantitative and rigorous theory for nonequilibrium qu…
View article: Absorption to fluctuating bunching states in nonunitary boson dynamics
Absorption to fluctuating bunching states in nonunitary boson dynamics Open
We show that noisy nonunitary dynamics of bosons drives arbitrary initial states into a novel , where all bosons occupy one time-dependent mode. We propose a concept of the noisy spectral gap, a generalization of the spectral gap in noisel…
View article: Quasiparticles of decoherence processes in open quantum many-body systems: Incoherentons
Quasiparticles of decoherence processes in open quantum many-body systems: Incoherentons Open
The relaxation dynamics of an open quantum system is determined by the competition between the coherent Hamiltonian dynamics of a system and the dissipative dynamics due to interactions with environments. It is therefore of fundamental int…
View article: Speed limits to fluctuation dynamics
Speed limits to fluctuation dynamics Open
Fluctuation dynamics of an experimentally measured observable offer a primary signal for nonequilibrium systems, along with dynamics of the mean. While universal speed limits for the mean have actively been studied recently, constraints fo…
View article: Absorption to Fluctuating Bunching States in Non-Unitary Boson Dynamics
Absorption to Fluctuating Bunching States in Non-Unitary Boson Dynamics Open
We show that noisy nonunitary dynamics of bosons drives arbitrary initial states into a novel fluctuating bunching state, where all bosons occupy one time-dependent mode. We propose a concept of the noisy spectral gap, a generalization of …
View article: Violation of Eigenstate Thermalization Hypothesis in Quantum Field Theories with Higher-Form Symmetry
Violation of Eigenstate Thermalization Hypothesis in Quantum Field Theories with Higher-Form Symmetry Open
We elucidate how the presence of higher-form symmetries affects the dynamics of thermalization in isolated quantum systems. Under reasonable assumptions, we analytically show that a $p$-form symmetry in a $(d+1)$-dimensional quantum field …
View article: Quantum Velocity Limits for Multiple Observables: Conservation Laws, Correlations, and Macroscopic Systems
Quantum Velocity Limits for Multiple Observables: Conservation Laws, Correlations, and Macroscopic Systems Open
How multiple observables mutually influence their dynamics has been a crucial issue in statistical mechanics. We introduce a new concept, "quantum velocity limits," to establish a quantitative and rigorous theory for non-equilibrium quantu…
View article: Bounds on eigenstate thermalization
Bounds on eigenstate thermalization Open
The eigenstate thermalization hypothesis (ETH), which asserts that every eigenstate of a many-body quantum system is indistinguishable from a thermal ensemble, plays a pivotal role in understanding thermalization of isolated quantum system…
View article: Distinguishability transitions in nonunitary boson-sampling dynamics
Distinguishability transitions in nonunitary boson-sampling dynamics Open
We discover transitions characterized by distinguishability of bosons in nonunitary dynamics with parity-time (PT) symmetry. We show that PT-symmetry breaking, a unique transition in non-Hermitian open systems, enhances regions in which bo…
View article: Role of Topology in Relaxation of One-Dimensional Stochastic Processes
Role of Topology in Relaxation of One-Dimensional Stochastic Processes Open
Stochastic processes are commonly used models to describe dynamics of a wide variety of nonequilibrium phenomena ranging from electrical transport to biological motion. The transition matrix describing a stochastic process can be regarded …
View article: Localization properties in disordered quantum many-body dynamics under continuous measurement
Localization properties in disordered quantum many-body dynamics under continuous measurement Open
We study localization properties of continuously monitored dynamics and associated measurement-induced phase transitions in disordered quantum many-body systems on the basis of the quantum trajectory approach. By calculating the fidelity b…
View article: Quasiparticles of Decoherence Processes in Open Quantum Many-Body Systems: Incoherentons
Quasiparticles of Decoherence Processes in Open Quantum Many-Body Systems: Incoherentons Open
The relaxation dynamics of an open quantum system is determined by the competition between the coherent Hamiltonian dynamics of a system and the dissipative dynamics due to interactions with environments. It is therefore of fundamental int…
View article: Quantum Metrology Protected by Hilbert Space Fragmentation
Quantum Metrology Protected by Hilbert Space Fragmentation Open
We propose an entanglement-enhanced sensing scheme that is robust against spatially inhomogeneous always-on Ising interactions. Our strategy is to tailor coherent quantum dynamics employing the Hilbert-space fragmentation (HSF), a recently…
View article: Emergence of Hilbert Space Fragmentation in Ising Models with a Weak Transverse Field
Emergence of Hilbert Space Fragmentation in Ising Models with a Weak Transverse Field Open
The transverse-field Ising model is one of the fundamental models in quantum many-body systems, yet a full understanding of its dynamics remains elusive in higher than one dimension. Here, we show for the first time the breakdown of ergodi…
View article: Distinguishability Transitions in Non-Unitary Boson Sampling Dynamics
Distinguishability Transitions in Non-Unitary Boson Sampling Dynamics Open
We discover novel transitions characterized by distinguishability of bosons in non-unitary dynamics with parity-time ($\mathcal{PT}$) symmetry. We show that $\mathcal{PT}$ symmetry breaking, a unique transition in non-Hermitian open system…
View article: Eigenstate Thermalization in Long-Range Interacting Systems
Eigenstate Thermalization in Long-Range Interacting Systems Open
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 eigenstate thermalization hypothesis for system…
View article: Lindbladian Many-Body Localization
Lindbladian Many-Body Localization Open
We discover a novel localization transition that alters the dynamics of coherence in disordered many-body spin systems subject to Markovian dissipation. The transition occurs in the middle spectrum of the Lindbladian super-operator whose e…
View article: Universal constraint on nonlinear population dynamics
Universal constraint on nonlinear population dynamics Open
Ecological and evolutionary processes show various population dynamics depending on internal interactions and environmental changes. While crucial in predicting biological processes, discovering general relations for such nonlinear dynamic…
View article: Speed Limits for Macroscopic Transitions
Speed Limits for Macroscopic Transitions Open
Speed of state transitions in macroscopic systems is a crucial concept for foundations of nonequilibrium statistical mechanics as well as various applications in quantum technology represented by optimal quantum control. While extensive st…
View article: Bounds in Nonequilibrium Quantum Dynamics
Bounds in Nonequilibrium Quantum Dynamics Open
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 open quantum systems and classical stoc…
View article: Impact of Dissipation on Universal Fluctuation Dynamics in Open Quantum Systems
Impact of Dissipation on Universal Fluctuation Dynamics in Open Quantum Systems Open
Recent experimental and theoretical works have uncovered nontrivial quantum dynamics due to external dissipation. Using an exact numerical method and a renormalization-group-based analytical technique, we theoretically elucidate that dissi…