439 citations · 1.8k across the 39 of their papers we have counts for
40 papers
Toward a Complexity Classification of High-Temperature Bosons: Computational Tractability and Power-Law Clustering
Xin-Hai Tong, Tomotaka Kuwahara
Determining when quantum many-body systems admit simple, efficiently simulable structure is a central problem. High-temperature thermal states are a natural candidate for such simp…
Prethermal inverse Mpemba effect
Koudai Sugimoto, Tomotaka Kuwahara, Keiji Saito
The inverse Mpemba effect is a counterintuitive phenomenon in which a system, initially in thermal equilibrium and prepared at different temperatures below that of the final equili…
Trotterization is substantially efficient for low-energy states
Kaoru Mizuta, Tomotaka Kuwahara
Trotterization is one of the central approaches for simulating quantum many-body dynamics on quantum computers or tensor networks. In addition to its simple implementation, recent…
Clustering of Conditional Mutual Information via Quantum Belief-Propagation Channels
Kohtaro Kato, Tomotaka Kuwahara
Conditional mutual information (CMI) has recently attracted significant attention as a key quantity for characterizing quantum correlations in many-body systems. While it is conjec…
Macroscopic Particle Transport in Dissipative Long-Range Bosonic Systems
Hongchao Li, Cheng Shang, Tomotaka Kuwahara +1
Dissipation in quantum many-body systems provides a more general and experimentally realistic perspective on particle transport than closed quantum systems. In this work, we determ…
Entanglement area law in interacting bosons from the Bose-Hubbard model to 4 theory and beyond
Donghoon Kim, Tomotaka Kuwahara
The entanglement area law is a universal principle that characterizes quantum many-body phases and underpins tensor network algorithms. Traditionally, its validity has been limited…
Clustering Theorem for Bose-Hubbard class Gibbs states
Xin-Hai Tong, Tomotaka Kuwahara, Zongping Gong
We establish the exponential clustering of correlation functions for the high-temperature Gibbs states of Bose-Hubbard type models. To overcome the technical difficulties arising f…
Quantum complexity and generalized area law in fully connected models
Donghoon Kim, Tomotaka Kuwahara
The area law for entanglement entropy captures a fundamental constraint on the complexity of quantum many-body ground states and enables their efficient description. While the area…
Provably Efficient Simulation of 1D Long-Range Interacting Systems at Any Temperature
Rakesh Achutha, Donghoon Kim, Yusuke Kimura +1
We introduce a method that ensures efficient computation of one-dimensional quantum systems with long-range interactions across all temperatures. Our algorithm operates within a qu…
Clustering of conditional mutual information and quantum Markov structure at arbitrary temperatures
Tomotaka Kuwahara
Recent investigations have unveiled exotic quantum phases that elude characterization by simple bipartite correlation functions. In these phases, long-range entanglement arising fr…
Symmetry-enhanced Lieb-Robinson bounds for a class of Bose-Hubbard type Hamiltonians
Tomotaka Kuwahara, Marius Lemm
Several recent works have derived Lieb-Robinson bounds (LRBs) for Bose-Hubbard-type Hamiltonians. For certain structured initial states, e.g., vacuum perturbations or near-stationa…
Thermal Area Law in Long-Range Interacting Systems
Donghoon Kim, Tomotaka Kuwahara, Keiji Saito
The area law of the bipartite information measure characterizes one of the most fundamental aspects of quantum many-body physics. In thermal equilibrium, the area law for the mutua…
Clustering theorem in 1D long-range interacting systems at arbitrary temperatures
Yusuke Kimura, Tomotaka Kuwahara
This paper delves into a fundamental aspect of quantum statistical mechanics -- the absence of thermal phase transitions in one-dimensional (1D) systems. Originating from Ising's a…
Fidelity-dissipation relations in quantum gates
Tan Van Vu, Tomotaka Kuwahara, Keiji Saito
Accurate quantum computing relies on the precision of quantum gates. However, quantum gates in practice are generally affected by dissipative environments, which can significantly…
Optimal light cone for macroscopic particle transport in long-range systems: A quantum speed limit approach
Tan Van Vu, Tomotaka Kuwahara, Keiji Saito
Understanding the ultimate rate at which information propagates is a pivotal issue in nonequilibrium physics. Nevertheless, the task of elucidating the propagation speed inherent i…
Effective light cone and digital quantum simulation of interacting bosons
Tomotaka Kuwahara, Tan Van Vu, Keiji Saito
The speed limit of information propagation is one of the most fundamental features in non-equilibrium physics. The region of information propagation by finite-time dynamics is appr…
Exponential clustering of bipartite quantum entanglement at arbitrary temperatures
Tomotaka Kuwahara, Keiji Saito
Macroscopic quantum effects play central roles in the appearance of inexplicable phenomena in low-temperature quantum many-body physics. Such macroscopic quantumness is often evalu…
Fate of measurement-induced phase transition in long-range interactions
Takaaki Minato, Koudai Sugimoto, Tomotaka Kuwahara +1
We consider quantum many-body dynamics under quantum measurements, where the measurement-induced phase transitions (MIPs) occur when changing the frequency of the measurement. In t…
Lieb-Robinson bound and almost-linear light-cone in interacting boson systems
Tomotaka Kuwahara, Keiji Saito
In this work, we investigate how quickly local perturbations propagate in interacting boson systems with Bose-Hubbard-type Hamiltonians. In general, these systems have unbounded lo…
Absence of fast scrambling in thermodynamically stable long-range interacting systems
Tomotaka Kuwahara, Keiji Saito
In this study, we investigate out-of-time-order correlators (OTOCs) in systems with power-law decaying interactions such as , where is the distance. In such systems, th…
Improved thermal area law and quasi-linear time algorithm for quantum Gibbs states
Tomotaka Kuwahara, Álvaro M. Alhambra, Anurag Anshu
One of the most fundamental problems in quantum many-body physics is the characterization of correlations among thermal states. Of particular relevance is the thermal area law, whi…
Sample-efficient learning of quantum many-body systems
Anurag Anshu, Srinivasan Arunachalam, Tomotaka Kuwahara +1
We study the problem of learning the Hamiltonian of a quantum many-body system given samples from its Gibbs (thermal) state. The classical analog of this problem, known as learning…
Many-body scar state intrinsic to periodically driven system: Rigorous results
Sho Sugiura, Tomotaka Kuwahara, Keiji Saito
The violation of the Floquet version of eigenstate thermalization hypothesis is systematically discussed with realistic Hamiltonians. Our model is based on the PXP type interaction…
Strictly linear light cones in long-range interacting systems of arbitrary dimensions
Tomotaka Kuwahara, Keiji Saito
In locally interacting quantum many-body systems, the velocity of information propagation is finitely bounded and a linear light cone can be defined. Outside the light cone, the am…