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The study of entanglement in the symmetry sectors of a theory has recently attracted a lot of attention since it provides better understanding of some aspects of quantum many-body systems. In this paper, we extend this analysis to the case…

Statistical Mechanics · Physics 2023-06-01 Michele Fossati , Filiberto Ares , Pasquale Calabrese

This study investigates the quantum effects in transverse-field Ising spin glass models with rotationally invariant random interactions. The primary aim is to evaluate the validity of a quasi-static approximation that captures the…

Disordered Systems and Neural Networks · Physics 2025-10-10 Yoshinori Hara , Yoshiyuki Kabashima

We combine the finite size scaling method with the meshfree spectral method to calculate quantum critical parameters for a given Hamiltonian. The basic idea is to expand the exact wave function in a finite exponential basis set and…

Quantum Physics · Physics 2014-02-07 Fahhad H Alharbi , Sabre Kais

We show how quantum metrology protocols that seek to estimate the parameters of a Hamiltonian that exhibits a quantum phase transition can be efficiently simulated on an exponentially smaller quantum computer. Specifically, by exploiting…

Quantum Physics · Physics 2016-12-28 W. L. Boyajian , M. Skotiniotis , W. Dür , B. Kraus

In this work, we investigate the quantum phase transition in a non-Hermitian XY spin chain. The phase diagram shows that the critical points of Ising phase transition expand into a critical transition zone after introducing a non-Hermitian…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Yu-Guo Liu , Lu Xu , Zhi Li

A conventional quantum phase transition (QPT) occurs not only at zero temperature, but also exhibits finite-temperature quantum criticality. Motivated by the discovery of the pseudo-Hermiticity of non-Hermitian systems, we explore the…

Quantum Physics · Physics 2015-12-09 Ci. Li , Zhi. Song

A $\mathcal{PT}$-symmetric, non-Hermitian Hamiltonian in the $\mathcal{PT}$-unbroken regime can lead to unitary dynamics under the appropriate choice of the Hilbert space. The Hilbert space is determined by a Hamiltonian-compatible inner…

Quantum Physics · Physics 2025-03-19 Himanshu Badhani , Subhashish Banerjee , C. M. Chandrashekar

In the present paper we have analysed a fermionic infinite-ranged quantum Heisenberg spin glass (s=1/2) with a BCS coupling in real space in the presence of an applied magnetic field. This model has been obtained by tracing out the…

Statistical Mechanics · Physics 2009-10-31 S. G. Magalhaes , A. A. Schmidt

We study the quantum dynamics of a non-interacting spin ensemble under the effect of a reservoir by applying the framework of the non-Hermitian Hamiltonian operators. Theoretically, the two-level model describes the quantum spin system and…

Quantum Physics · Physics 2022-03-14 D. Cius , A. Consuelo-Leal , A. G. Araujo-Ferreira , R. Auccaise

We study the ground-state phase diagram of a spin-1 Heisenberg chain with staggered long-range (LR) interactions decaying as $\propto r^{-\alpha}$ using a quantum Monte Carlo approach based on the split-spin representation. This formulation…

Strongly Correlated Electrons · Physics 2026-04-23 Justin Tim-Lok Chau , Jiarui Zhao , Nicolas Laflorencie , Zi Yang Meng

We propose an experimentally accessible scheme to determine lower bounds on the quantum Fisher information (QFI), which ascertains multipartite entanglement or usefulness for quantum metrology. The scheme is based on comparing the…

Quantum Physics · Physics 2016-03-14 Florian Fröwis , Pavel Sekatski , Wolfgang Dür

In quantum optics and condensed matter physics non-Hermitian phenomena are often studied under the assumption of an open physical system. However, there are examples of intrinsically non-Hermitian, though often $\mathcal{PT}$ (parity-time)…

Quantum Physics · Physics 2026-03-30 Eduard Naichuk , Jeroen van den Brink , Flavio S. Nogueira

Energetic coherence is indispensable for various operations, including precise measurement of time and acceleration of quantum manipulations. Since energetic coherence is fragile, it is essential to understand the limits in distillation and…

Quantum Physics · Physics 2023-11-21 Koji Yamaguchi , Hiroyasu Tajima

Understanding how well future cosmological experiments can reconstruct the mechanism that generated primordial inhomogeneities is key to assessing the extent to which cosmology can inform fundamental physics. In this work, we apply a…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-23 Michał Piotrak , Thomas Colas , Ana Alonso-Serrano , Alessio Serafini

We find that heavy fermion systems can have bulk "Fermi arcs", with the use of the non-Hermitian topological theory. In an interacting electron system, the microscopic many-body Hamiltonian is Hermitian, but the one-body quasiparticle…

Strongly Correlated Electrons · Physics 2020-11-30 Yuki Nagai , Yang Qi , Hiroki Isobe , Vladyslav Kozii , Liang Fu

For non-Hermitian quantum models, the dynamics is apparently not reflected by the static properties, e.g., the complex energy spectrum, because of the nonorthogonality of the right eigenvectors, the nonunitarity of the time evolution, the…

Quantum Physics · Physics 2021-01-12 Li-Jun Lang , Yijiao Weng , Yunhui Zhang , Enhong Cheng , Qixia Liang

Radical-ion pairs and their reactions have triggered the study of quantum effects in biological systems. This is because they exhibit a number of effects best understood within quantum information science, and at the same time are central…

Quantum Physics · Physics 2017-04-06 K. M. Vitalis , I. K. Kominis

Engineering quantum bath networks through non-Hermitian subsystem Hamiltonians has recently emerged as a promising strategy for qubit cooling, state stabilization, and fault-tolerant quantum computation. However, scaling these systems while…

We show that quantification of the performance of quantum-enhanced measurement schemes based on the concept of quantum Fisher information yields asymptotically equivalent results as the rigorous Bayesian approach, provided generic…

Quantum Physics · Physics 2015-01-13 Marcin Jarzyna , Rafal Demkowicz-Dobrzanski

We propose a scheme to obtain the Heisenberg-limited parameter estimation precision by immersing atoms in a thermally equilibrated quasi-one-dimensional dipolar Bose-Einstein condensate reservoir. We show that the collisions between the…

Quantum Physics · Physics 2018-01-03 Qing-Shou Tan , Ji-Bing Yuan , Guang-Ri Jin , Le-Man Kuang
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