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Hamiltonian learning protocols are essential tools to benchmark quantum computers and simulators. Yet rigorous methods for time-dependent Hamiltonians and Lindbladians remain scarce despite their wide use. We close this gap by learning the…

Quantum Physics · Physics 2025-10-10 Daniel Stilck França , Tim Möbus , Cambyse Rouzé , Albert H. Werner

We present a new class of exponential integrators for ordinary differential equations. They are locally exact, i.e., they preserve the linearization of the original system at every point. Their construction consists in modifying existing…

Numerical Analysis · Mathematics 2011-04-08 Jan L. Cieśliński

The characterization of many-body correlations provides a powerful tool for analyzing correlated quantum materials. However, experimental extraction of quantum entanglement in correlated electronic systems remains an open problem in…

Strongly Correlated Electrons · Physics 2023-04-21 Faluke Aikebaier , Teemu Ojanen , Jose L. Lado

This paper develops a new approach to small time local attainability of smooth manifolds of any dimension, possibly with boundary and to prove H\"older continuity of the minimum time function. We give explicit pointwise conditions of any…

Optimization and Control · Mathematics 2023-04-21 Pierpaolo Soravia

The Hamiltonian of a quantum system governs the dynamics of the system via the Schrodinger equation. In this paper, the Hamiltonian is reconstructed in the Pauli basis using measurables on random states forming a time series dataset. The…

Quantum Physics · Physics 2023-05-10 Rishabh Gupta , Raja Selvarajan , Manas Sajjan , Raphael D. Levine , Sabre Kais

Correlated many-body problems ubiquitously appear in various fields of physics such as condensed matter physics, nuclear physics, and statistical physics. However, due to the interplay of the large number of degrees of freedom, it is…

Strongly Correlated Electrons · Physics 2018-02-12 Hiroyuki Fujita , Yuya O. Nakagawa , Sho Sugiura , Masaki Oshikawa

Embedding calculations that find approximate solutions to the Schr\"{o}dinger equation for large molecules and realistic solids are performed commonly in a three step procedure involving (i) construction of a model system with effective…

Strongly Correlated Electrons · Physics 2016-11-15 Alexander A. Rusakov , Jordan J. Phillips , Dominika Zgid

Many important physical systems can be described as the evolution of a Hamiltonian system, which has the important property of being conservative, that is, energy is conserved throughout the evolution. Physics Informed Neural Networks and…

Machine Learning · Computer Science 2025-12-10 Harsh Choudhary , Chandan Gupta , Vyacheslav Kungurtsev , Melvin Leok , Georgios Korpas

We study the conditions for obtaining maximally multipartite entangled states (MMES) as non-degenerate eigenstates of Hamiltonians that involve only short-range interactions. We investigate small-size systems (with a number of qubits…

Quantum Physics · Physics 2010-11-04 P. Facchi , G. Florio , S. Pascazio , F. Pepe

Exactly solvable Hamiltonians are useful in the study of quantum many-body systems using quantum computers. In the variational quantum eigensolver, a decomposition of the target Hamiltonian into exactly solvable fragments can be used for…

Quantum Physics · Physics 2024-02-15 Smik Patel , Artur F. Izmaylov

Learning about a Hamiltonian $H$ from its time evolution $e^{-iHt}$ is a fundamental task in quantum science. A flurry of recent work has developed powerful new algorithms with provable guarantees for this task, for a variety of natural…

Quantum Physics · Physics 2026-04-20 Ziyun Chen , Jerry Li , Joseph Slote

Local non-Hermitian (NH) quantum systems generically exhibit breakdown of Lieb-Robinson (LR) bounds, motivating study of whether new locality measures might shed light not seen by existing measures. In this paper we extend the standard…

Quantum Physics · Physics 2024-09-16 Brian Barch

In this work, we consider a fundamental task in quantum many-body physics - finding and learning ground states of quantum Hamiltonians and their properties. Recent works have studied the task of predicting the ground state expectation value…

Quantum Physics · Physics 2025-01-16 Štěpán Šmíd , Roberto Bondesan

Domain specific localization of eigenstates has been a persistent observation for systems with local symmetries. The underlying mechanism for this localization behaviour has however remained elusive. We provide here an analysis of locally…

Quantum Physics · Physics 2024-01-19 Peter Schmelcher

We consider the problem of learning the Hamiltonian of a quantum system from estimates of Gibbs-state expectation values. Various methods for achieving this task were proposed recently, both from a practical and theoretical point of view.…

Quantum Physics · Physics 2024-10-31 Adam Artymowicz , Hamza Fawzi , Omar Fawzi , Samuel O. Scalet

We consider two related tasks: (a) estimating a parameterisation of a given Gibbs state and expectation values of Lipschitz observables on this state; and (b) learning the expectation values of local observables within a thermal or quantum…

Quantum Physics · Physics 2024-09-09 Emilio Onorati , Cambyse Rouzé , Daniel Stilck França , James D. Watson

Limited resources motivate decomposing large-scale problems into smaller,``local" subsystems and stitching together the so-found solutions. We explore the physics underlying this approach and discuss the concept of ``local hardness", i.e.,…

Disordered Systems and Neural Networks · Physics 2025-12-24 Mutian Shen , Gerardo Ortiz , Zhiqiao Dong , Martin Weigel , Zohar Nussinov

The adiabatic quantum algorithm has drawn intense interest as a potential approach to accelerating optimization tasks using quantum computation. The algorithm is most naturally realised in systems which support Hamiltonian evolution, rather…

Quantum Physics · Physics 2019-10-02 Liming Zhao , Carlos A. Perez-Delgado , Simon C. Benjamin , Joseph F. Fitzsimons

The Hamiltonian of an isolated quantum mechanical system determines its dynamics and physical behaviour. This study investigates the possibility of learning and utilising a system's Hamiltonian and its variational thermal state estimation…

Quantum Physics · Physics 2023-12-22 Jack Y. Araz , Michael Spannowsky

The problem of finding superintegrable Hamiltonians and their integrals of motion can be reduced to solving a series of compatibility equations that result from the overdetermination of the commutator or Poisson bracket relations. The…

Mathematical Physics · Physics 2025-12-23 Ian Marquette , Anthony Parr