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This work is concerned with the excited state quantum phase transitions (ESQPTs) defined in Ann.Phys. 323, 1106 (2008). In many-body models that exhibit such transitions, the ground state quantum phase transition (QPT) occurs in parallel…

Statistical Mechanics · Physics 2018-01-08 Francisco Pérez-Bernal , Lea F. Santos

Solving finite-temperature properties of quantum many-body systems is generally challenging to classical computers due to their high computational complexities. In this article, we present experiments to demonstrate a hybrid…

The preparation of thermal equilibrium states is important for the simulation of condensed-matter and cosmology systems using a quantum computer. We present a method to prepare such mixed states with unitary operators, and demonstrate this…

Artificial neural networks have been recently introduced as a general ansatz to compactly represent many- body wave functions. In conjunction with Variational Monte Carlo, this ansatz has been applied to find Hamil- tonian ground states and…

Strongly Correlated Electrons · Physics 2018-10-24 Kenny Choo , Giuseppe Carleo , Nicolas Regnault , Titus Neupert

Irreversibility, despite being a necessary condition for thermalization, still lacks a sound understanding in the context of isolated quantum many-body systems. In this work we approach this question by studying the behavior of generic…

Statistical Mechanics · Physics 2018-11-14 Markus Schmitt , Stefan Kehrein

The description of excited state dynamics in multichromophoric systems constitutes both a theoretical and experimental challenge in modern physical chemistry. An experimental protocol which can systematically characterize both coherent and…

Quantum Physics · Physics 2011-10-31 Joel Yuen-Zhou , Jacob J. Krich , Masoud Mohseni , Alán Aspuru-Guzik

We propose a type of phase transition in quantum many-body systems, which occurs in highly excited quantum many-body scar states, while most of the spectrum is largely unaffected. Such scar state phase transitions can be realized by…

Quantum Physics · Physics 2024-10-10 Peter Græns Larsen , Anne E. B. Nielsen

We design faster-than-adiabatic state transfers (switching of quantum numbers) in time-dependent coupled-oscillator Hamiltonians. The manipulation to drive the process is found using a two-dimensional invariant recently proposed in S.…

Quantum Physics · Physics 2022-06-22 Xiao-Jing Lu , Ion Lizuain , J. G. Muga

The exact ground state of a strongly interacting quantum many-body system can be obtained by evolving a trial state with finite overlap with the ground state to infinite imaginary time. In this work, we use a newly discovered fourth order…

Condensed Matter · Physics 2009-11-10 Orion Ciftja , Siu A. Chin

We propose and analyze a new approach to the coherent control and manipulation of quantum degrees of freedom in disordered, interacting systems in the many-body localized phase. Our approach leverages a number of unique features of…

Quantum Physics · Physics 2015-08-31 Soonwon Choi , Norman Y. Yao , Sarang Gopalakrishnan , Mikhail D. Lukin

We investigate how dynamical decoupling methods may be used to manipulate the time evolution of quantum many-body systems. These methods consist of sequences of external control operations designed to induce a desired dynamics. The systems…

Quantum Physics · Physics 2015-05-18 Julie Dinerman , Lea F. Santos

We lay out an experiment to realize time-reversal invariant topological insulators in alkali atomic gases. We introduce an original method to synthesize a gauge field in the near-field of an atom-chip, which effectively mimics the effects…

Preparation of a target quantum many-body state on quantum simulators is one of the significant steps in quantum science and technology. With a small number of qubits, a few quantum states, such as the Greenberger-Horne-Zeilinger state,…

Quantum Physics · Physics 2023-07-28 Donggyu Kim , Eun-Gook Moon

We consider an arbitrary quantum system coupled non perturbatively to a large arbitrary and fully quantum environment. In [G. Ithier and F. Benaych-Georges, Phys. Rev. A 96, 012108 (2017)] the typicality of the dynamics of such an embedded…

Quantum Physics · Physics 2017-12-20 Grégoire Ithier , Saeed Ascroft , Florent Benaych-Georges

Simulations of quantum chemistry and quantum materials are believed to be among the most important potential applications of quantum information processors, but realizing practical quantum advantage for such problems is challenging. Here,…

Accurately determining ground-state properties of quantum many-body systems remains one of the major challenges of quantum simulation. In this work, we present a protocol for estimating the ground-state energy using only global time…

A dynamical quantum phase transition can occur during time evolution of sudden quenched quantum systems across a phase transition. It corresponds to the nonanalytic behavior at a critical time of the rate function of the quantum state…

Quantum Physics · Physics 2019-05-14 Xue-Yi Guo , Chao Yang , Yu Zeng , Yi Peng , He-Kang Li , Hui Deng , Yi-Rong Jin , Shu Chen , Dongning Zheng , Heng Fan

In the pursuit of numerically identifying the ground state of quantum many-body systems, approximate quantum wavefunction ansatzes are commonly employed. This study focuses on the spectral decomposition of these approximate quantum…

Quantum Physics · Physics 2025-08-29 Yu-Qin Chen , Shi-Xin Zhang

We propose a natural application of Quantum Linear Systems Problem (QLSP) solvers such as the HHL algorithm to efficiently prepare highly excited interior eigenstates of physical Hamiltonians in a variational and targeted manner. This is…

Quantum Physics · Physics 2023-10-13 Shao-Hen Chiew , Leong-Chuan Kwek

A crucial milestone in the field of quantum simulation and computation is to demonstrate that a quantum device can compute certain tasks that are impossible to reproduce by a classical computer with any reasonable resources. Such a…