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Identifying symmetries in quantum dynamics, such as identity or time-reversal invariance, is a crucial challenge with profound implications for quantum technologies. We introduce a unified framework combining group representation theory and…

Quantum Physics · Physics 2025-02-04 Masahito Hayashi , Yu-Ao Chen , Chenghong Zhu , Xin Wang

Quantum computation has been growing rapidly in both theory and experiments. In particular, quantum computing devices with a large number of qubits have been developed by IBM, Google, IonQ, and others. The current quantum computing devices…

Quantum Physics · Physics 2021-02-10 Rishabh Gupta , Rongxin Xia , Raphael D. Levine , Sabre Kais

K. It\^{o} characterised in \cite{ito} zero-mean stationary Gauss Markov-processes evolving on a class of infinite-dimensional spaces. In this work we extend the work of It\^{o} in the case of Hilbert spaces: Gauss-Markov families that are…

Probability · Mathematics 2013-07-11 Ben Goldys , Szymon Peszat , Jerzy Zabczyk

Quantum Process Tomography (QPT) is a powerful tool to characterize quantum operations, but it requires considerable resources making it impractical for more than 2-qubit systems. This work proposes an alternative approach that requires…

Quantum Physics · Physics 2022-05-18 Vicente Leyton-Ortega , Tyler Kharazi , Raphael C. Pooser

Recent understanding of the thermodynamics of small-scale systems have enabled the characterization of the thermodynamic requirements of implementing quantum processes for fixed input states. Here, we extend these results to construct…

Quantum Physics · Physics 2021-07-26 Philippe Faist , Mario Berta , Fernando G. S. L. Brandao

A quantum system's state is identified with a density matrix. Though their probabilistic interpretation is rooted in ensemble theory, density matrices embody a known shortcoming. They do not completely express an ensemble's physical…

Quantum Physics · Physics 2021-06-30 Fabio Anza , James P. Crutchfield

We develop a rigorous and implementable framework for Gibbs sampling of infinite-dimensional quantum systems governed by unbounded Hamiltonians. Extending dissipative Gibbs samplers beyond finite dimensions raises fundamental obstacles,…

Quantum Physics · Physics 2026-04-02 Simon Becker , Cambyse Rouzé , Robert Salzmann

The dissipation generated during a quasistatic thermodynamic process can be characterised by introducing a metric on the space of Gibbs states, in such a way that minimally-dissipating protocols correspond to geodesic trajectories. Here, we…

Quantum Physics · Physics 2019-10-25 Matteo Scandi , Martí Perarnau-Llobet

In the near future, a major challenge in quantum computing is to scale up robust qubit prototypes to practical problem sizes and to implement comprehensive error correction for computational precision. Due to inevitable quantum…

Quantum Physics · Physics 2018-03-28 Joni Ikonen , Juha Salmilehto , Mikko Möttönen

Repeated computations on the same molecular system, but with different geometries, are often performed in quantum chemistry, for instance, in ab-initio molecular dynamics simulations or geometry optimizations. While many efficient…

Chemical Physics · Physics 2020-12-02 E. Polack , A. Mikhalev , Geneviève Dusson , B. Stamm , F. Lipparini

Scalable characterization of quantum processors is crucial for mitigating noise and imperfections. While randomized measurement protocols enable efficient access to local observables, inferring a globally consistent description of…

Quantum Physics · Physics 2026-03-10 Zidu Liu , Dominik S. Wild

Topological symmetries, invertible and otherwise, play a fundamental role in the investigation of quantum field theories. Despite their ubiquitous importance across a multitude of disciplines ranging from string theory to condensed matter…

Quantum Physics · Physics 2025-10-17 Christopher Lamb , Robert M. Konik , Hubert Saleur , Ananda Roy

We propose a numerical technique based on a combination of short-iterative Lanczos and exact diagonalization methods, suitable for simulating the time evolution of the reduced density matrix of a single qubit interacting with an…

In this thesis, we present optimization tools for different problems in quantum information theory. First, we introduce an algorithm for quantum estate estimation. The algorithm consists of orthogonal projections on intersecting…

Quantum Physics · Physics 2022-04-19 Daniel Uzcategui Contreras

Information Geometry generalizes to infinite dimension by modeling the tangent space of the relevant manifold of probability densities with exponential Orlicz spaces. We review here several properties of the exponential manifold on a…

Statistics Theory · Mathematics 2023-07-19 Bertrand Lods , Giovanni Pistone

In standard thermodynamics, internal energy is a state function, independent of process rates. We show that this structure breaks down in open quantum systems undergoing thermalization. Within Gorini-Kossakowski-Lindblad-Sudarshan (GKLS)…

Statistical Mechanics · Physics 2026-05-12 Hyeong-Chan Kim , Youngone Lee

Variational quantum algorithms, optimized using gradient-based methods, often exhibit sub-optimal convergence performance due to their dependence on Euclidean geometry. Quantum natural gradient descent (QNGD) is a more efficient method that…

Quantum Physics · Physics 2025-06-05 Mohammad Aamir Sohail , Mohsen Heidari , S. Sandeep Pradhan

Landauer's principle introduces a symmetry between computational and physical processes: erasure of information, a logically irreversible operation, must be underlain by an irreversible transformation dissipating energy. Monitoring micro-…

Quantum gate set tomography (GST) has emerged as a promising method for the full characterization of quantum logic gates. In contrast to quantum process tomography (QPT), GST self-consistently and correctly accounts for state preparation…

Quantum Physics · Physics 2015-09-11 Daniel Greenbaum

The relevance of the concept of Fisher information is increasing in both statistical physics and quantum computing. From a statistical mechanical standpoint, the application of Fisher information in the kinetic theory of gases is…

Quantum Physics · Physics 2018-05-09 Carlo Cafaro , Paul M. Alsing