Violation of Eigenstate Thermalization Hypothesis in Quantum Field Theories with Higher-Form Symmetry

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 theory leads to the breakdown of the eigenstate thermalization hypothesis for many nontrivial $(d-p)$-dimensional observables. For higher-form (i.e., $p\geq 1$) symmetry, this indicates the absence of thermalization for observables that are non-local but much smaller than the whole system size. We numerically demonstrate this argument for the (2+1)-dimensional $\mathbb{Z}_2$ lattice gauge theory. While local observables such as the plaquette operator thermalize, the non-local observable exciting a magnetic dipole instead relaxes to the generalized Gibbs ensemble that takes account of the $\mathbb{Z}_2$ 1-form symmetry.Comment: 7 pages, 4 figures, supplemental material with 6 pages and 1 figure; v2: minor modifications, references added, published version in PR

Correlation between aerobic threshold and cardiopulmonary response to exercise onset in patients with myocardial infarction

Purpose: This study aimed to identify the correlation between aerobic threshold (AT) and cardiopulmonary response at the start of exercise in patients with myocardial infarction (MI). Subjects and Methods: Thirty-one male patients with MI underwent a sub-maximal cardiopulmonary exercise test with expiratory gas analysis to determine their peak oxygen uptake (V̇O₂) level, using Ramp protocol. Results: The patients demonstrated an extended time constant (TC) and decline in AT in this study. Extended TC suggested impaired cardiac function due to reduced left ventricular ejection fraction (LVEF), as well as an LVEF of 59.8% on average. However, there was no significant correlation between TC and AT. Pearson product-moment correlation coefficients were 0.56 between AT and area under the oxygen uptake curve (V̇O₂AUC), -0.22 between TC and V̇O₂AUC, and -0.23 between AT and TC. Conclusion: V̇O₂AUC is representative of oxygen utilization and is correlated with AT in patients with MI.首都大学東京学位論文 乙第192号 副論

Molecular Dynamics Simulation of Grain Boundary Formation and Migration in Silicon

Molecular dynamics simulation using Tersoff potential was carried out to investigate the formation and the migration of (010) AE5 twist boundary in silicon. Effects of carbon atoms on the grain boundary formation and the grain boundary migration were also investigated. Amorphous thin layers remained at the twist boundary even after crystallization, and changes in the thickness of this layers caused grain boundary migration. When carbon atoms were segregated at the twist boundary, these atoms prevented shrinkage of an amorphous thin layer, and the grain boundary migration was retarded. Precipitated carbon atoms within the grain produces a strain field and this strain field possibly became driving force for the grain boundary migration