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Reconstructing the Hamiltonian of a quantum system is an essential task for characterizing and certifying quantum processors and simulators. Existing techniques either rely on projective measurements of the system before and after coherent…

We present an algorithm for marginalising changepoints in time-series models that assume a fixed number of unknown changepoints. Our algorithm is differentiable with respect to its inputs, which are the values of latent random variables…

Machine Learning · Computer Science 2019-11-25 Hyoungjin Lim , Gwonsoo Che , Wonyeol Lee , Hongseok Yang

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

Using two extremely different models of glass formers in two and three dimensions we demonstrate how to encode the subtle changes in the geometric rearrangement of particles during the scenario of the glass transition. We construct a…

Statistical Mechanics · Physics 2015-05-13 Laurent Boue , Edan Lerner , Itamar Procaccia , Jacques Zylberg

Training data attribution (TDA) methods ask which training documents are responsible for a model behavior. However, models often learn broad concepts shared across many examples. Moreover, existing TDA methods are supervised -- they require…

Artificial Intelligence · Computer Science 2026-03-18 J Rosser

In the case of quantum systems interacting with multiple environments, the time-evolution of the reduced density matrix is described by the Liouvillian. For a variety of physical observables, the long-time limit or steady state solution is…

Quantum Physics · Physics 2022-01-05 Rodrigo A. Vargas-Hernández , Ricky T. Q. Chen , Kenneth A. Jung , Paul Brumer

We develop a general approach for monitoring and controlling evolution of open quantum systems. In contrast to the master equations describing time evolution of density operators, here, we formulate a dynamical equation for the evolution of…

Quantum Physics · Physics 2009-08-09 M. Mohseni , A. T. Rezakhani

We present a variational principle for the extraction of a time-dependent orthonormal basis from random realizations of transient systems. The optimality condition of the variational principle leads to a closed-form evolution equation for…

Numerical Analysis · Mathematics 2020-07-01 Hessam Babaee

A construction of covariant quantum phase observables, for Hamiltonians with a finite number of energy eigenvalues, has been recently given by D. Arsenovic et al. [Phys. Rev. A 85, 044103 (2012)]. For Hamiltonians generating periodic…

Quantum Physics · Physics 2012-11-15 Michael J. W. Hall , David T. Pegg

We present a quantum algorithm based on repeated measurement to solve initial-value problems for nonlinear ordinary differential equations (ODEs), which may be generated from partial differential equations in plasma physics. We map a…

Quantum Physics · Physics 2025-04-30 Joseph Andress , Alexander Engel , Yuan Shi , Scott Parker

The dynamic of complex ordering systems with active rotational degrees of freedom exemplified by protein self-assembly is explored using a machine learning workflow that combines deep learning-based semantic segmentation and rotationally…

Soft Condensed Matter · Physics 2021-04-26 Sergei V. Kalinin , Shuai Zhang , Mani Valleti , Harley Pyles , David Baker , James J. De Yoreo , Maxim Ziatdinov

We consider an open quantum system which contains unstable states. The time evolution of the system can be described by an effective non-hermitian Hamiltonian H_{eff}, in accord with the Wigner--Weisskopf approximation, and an additional…

Quantum Physics · Physics 2011-08-04 Reinhold A. Bertlmann , Walter Grimus , Beatrix C. Hiesmayr

Quantum systems governed by time-dependent Hamiltonians pose significant challenges for the accurate computation of unitary time-evolution operators, which are essential for predicting quantum state dynamics. In this work, we introduce a…

Quantum Physics · Physics 2026-01-21 Antonio Guerra , Daniel Uzcategui-Contreras , Aldo Delgado , Esteban S. Gómez

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

In this work, we develop a mathematical framework to model a quantum system whose Hamiltonian may depend on the state of changing environment, that evolves according to a Markovian process. When the environment changes its state, the…

Quantum Physics · Physics 2023-08-17 Henryk Gzyl

Generalized Gibbs ensembles have been used as powerful tools to describe the steady state of integrable many-particle quantum systems after a sudden change of the Hamiltonian. Here we demonstrate numerically, that they can be used for a…

Strongly Correlated Electrons · Physics 2018-05-02 Florian Lange , Zala Lenarčič , Achim Rosch

We develop an optimization-based approach to the problem of reconstructing temperature-dependent material properties in complex thermo-fluid systems described by the equations for the conservation of mass, momentum and energy. Our goal is…

Fluid Dynamics · Physics 2013-04-11 Vladislav Bukshtynov , Bartosz Protas

The vast complexity is a daunting property of generic quantum states that poses a significant challenge for theoretical treatment, especially in non-equilibrium setups. Therefore, it is vital to recognize states which are locally less…

Quantum Physics · Physics 2022-07-28 Markus Schmitt , Zala Lenarčič

Gradient matching with Gaussian processes is a promising tool for learning parameters of ordinary differential equations (ODE's). The essence of gradient matching is to model the prior over state variables as a Gaussian process which…

Machine Learning · Statistics 2016-10-25 Nico S. Gorbach , Stefan Bauer , Joachim M. Buhmann

In this work we intend to study a class of time-dependent quantum systems with non-Hermitian Hamiltonians, particularly those whose Hermitian counterpart are important for the comprehension of posed problems in quantum optics and quantum…

Quantum Physics · Physics 2007-05-23 A. de Souza Dutra , M. B. Hott , V. G. C. S dos Santos