161 citations · 261 across the 22 of their papers we have counts for
24 papers
Absence of Spin-Glass Order on Migdal--Kadanoff Hierarchical Lattices near Three Dimensions
Manaka Okuyama, Masayuki Ohzeki
We derive a rigorous sufficient condition for the absence of spin-glass order in the Ising spin glass with symmetric binary couplings on Migdal--Kadanoff (MK) hierarchical lattices…
Griffiths inequalities and Gibbs-Bogoliubov inequality for general gauge glasses with Gaussian disorder on Nishimori line
Manaka Okuyama, Masayuki Ohzeki
We consider a class of gauge glass models with Gaussian disorder on the Nishimori line, including the Ising spin glass, the gauge glass, the gauge glass, and the gauge-i…
Existence of a Phase Transition in the One-Dimensional Ising Spin Glass Model with Long-Range Interactions on the Nishimori Line
Manaka Okuyama, Masayuki Ohzeki
Dyson [Commun. Math. Phys. 12, 91 (1969)] rigorously proved the existence of a phase transition in the one-dimensional Ising model with long-range interactions of the form …
Temperature chaos as a logical consequence of the reentrant transition in spin glasses
Hidetoshi Nishimori, Masayuki Ohzeki, Manaka Okuyama
Temperature chaos is a striking phenomenon in spin glasses, where even slight changes in temperature lead to a complete reconfiguration of the spin state. Another intriguing effect…
Existence of long-range order in random-field Ising model on Dyson hierarchical lattice
Manaka Okuyama, Masayuki Ohzeki
We study the random-field Ising model on a Dyson hierarchical lattice, where the interactions decay in a power-law-like form, , with respect to the distance. Witho…
Replica bound for Ising spin glass models in one dimension
Manaka Okuyama, Masayuki Ohzeki
The interpolation method is a powerful tool for rigorous analysis of mean-field spin glass models, both with and without dilution. In this study, we show that the interpolation met…
Free energy equivalence between mean-field models and nonsparsely diluted mean-field models
Manaka Okuyama, Masayuki Ohzeki
We studied nonsparsely diluted mean-field models that differ from sparsely diluted mean-field models, such as the Viana--Bray model. When the existence probability of each edge fol…
Toward mean-field bound for critical temperature on Nishimori line
Manaka Okuyama, Masayuki Ohzeki
The critical inverse temperature of the mean-field approximation establishes a lower bound of the true critical inverse temperature in a broad class of ferromagnetic spin models. T…
Threshold theorem in quantum annealing with deterministic analog control errors
Manaka Okuyama, Masayuki Ohzeki
We investigate the effect of deterministic analog control errors in the time-dependent Hamiltonian on isolated quantum dynamics. Deterministic analog control errors are formulated…
Mean-field theory is exact for Ising spin glass models with Kac potential in non-additive limit on Nishimori line
Manaka Okuyama, Masayuki Ohzeki
Recently, Mori [Phys. Rev. E 84, 031128 (2011)] has conjectured that the free energy of Ising spin glass models with the Kac potential in the non-additive limit, such as the power-…
Gibbs-Bogoliubov inequality on Nishimori line
Manaka Okuyama, Masayuki Ohzeki
The Gibbs-Bogoliubov inequality states that the free energy of a system is always lower than that calculated by a trial function. In this study, we show that a counterpart of the G…
Threshold theorem in isolated quantum dynamics with stochastic control errors
Manaka Okuyama, Kentaro Ohki, Masayuki Ohzeki
We investigate the effect of stochastic control errors in the time-dependent Hamiltonian on isolated quantum dynamics. The control errors are formulated as time-dependent stochasti…
Exact solution of free entropy for matrix-valued geometric Brownian motion with non-commutative matrices via the replica method
Manaka Okuyama, Masayuki Ohzeki
Geometric Brownian motion (GBM) is a standard model in stochastic differential equations. In this study, we consider a matrix-valued GBM with non-commutative matrices. Introduction…
Upper bound on the second derivative of the quenched pressure in spin-glass models: weak Griffiths second inequality
Manaka Okuyama, Masayuki Ohzeki
The Griffiths first and second inequalities have played an important role in the analysis of ferromagnetic models. In spin-glass models, although the counterpart of the Griffiths f…
Some inequalities for correlation functions of Ising models with quenched randomness
Manaka Okuyama, Masayuki Ohzeki
Correlation inequalities have played an essential role in the analysis of ferromagnetic models but have not been established in spin glass models. In this study, we obtain some cor…
Inequality for local energy of Ising models with quenched randomness and its application
Manaka Okuyama, Masayuki Ohzeki
In this study, we extend the lower bound on the average of the local energy of the Ising model with quenched randomness [J. Phys. Soc. Jpn. 76, 074711 (2007)] obtained for a symmet…
An exact solution of the partition function for mean-field quantum spin systems without the static approximation
Manaka Okuyama, Masayuki Ohzeki
Suzuki-Trotter decomposition is a well-known technique used to calculate the partition function of quantum spin systems, in which the imaginary-time dependence of the partition fun…
A useful fundamental speed limit for the imaginary-time Schrodinger equation
Manaka Okuyama, Masayuki Ohzeki
The quantum speed limit (QSL), or the energy-time uncertainty relation, gives a fundamental speed limit for quantum dynamics. Recently, Kieu [arXiv:1702.00603] derived a new class…
Comment on "Energy-time uncertainty relation for driven quantum systems" and "Quantum Speed Limit for Non-Markovian Dynamics"
Manaka Okuyama, Ryo Takahashi, Masayuki Ohzeki
Deffner and Lutz [J. Phys. A 46, 335302 (2013) and Phys. Rev. Lett. 111, 010402 (2013).] extended the Mandelstam-Tamm bound and the Margolus-Levitin bound to time-dependent and non…
Quantum Speed Limit is Not Quantum
Manaka Okuyama, Masayuki Ohzeki
The quantum speed limit (QSL), or the energy-time uncertainty relation, describes the fundamental maximum rate for quantum time evolution and has been regarded as being unique in q…
Quantum-Classical Correspondence of Shortcuts to Adiabaticity
Manaka Okuyama, Kazutaka Takahashi
We formulate the theory of shortcuts to adiabaticity in classical mechanics. For a reference Hamiltonian, the counterdiabatic term is constructed from the dispersionless Korteweg-d…
From Classical Nonlinear Integrable Systems to Quantum Shortcuts to Adiabaticity
Manaka Okuyama, Kazutaka Takahashi
Using shortcuts to adiabaticity, we solve the time-dependent Schroedinger equation that is reduced to a classical nonlinear integrable equation. For a given time-dependent Hamilton…
Anomalous behavior of the energy gap in the one-dimensional quantum XY model
Manaka Okuyama, Yuuki Yamanaka, Hidetoshi Nishimori +1
We re-examine the well-studied one dimensional spin-1/2 model to reveal its nontrivial energy spectrum, in particular the energy gap between the ground state and the first exc…
Anomalous behavior of the energy gap in the one-dimensional quantum XY model
Yuuki Yamanaka, Hidetoshi Nishimori
We show for the one-dimensional quantum model with that the energy gap between the ground and first excited states behaves anomalously as a function of the system size…