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Considering homogeneous four-dimensional space-time geometries within real projective geometry provides a mathematically well-defined framework to discuss their deformations and limits without the appearance of coordinate singularities. On…

Mathematical Physics · Physics 2025-05-22 Daniel Spitz

The Mori-Zwanzig projection operator formalism is one of the central tools of nonequilibrium statistical mechanics, allowing to derive macroscopic equations of motion from the microscopic dynamics through a systematic coarse-graining…

Statistical Mechanics · Physics 2020-06-18 Michael te Vrugt , Raphael Wittkowski

Approximations of optimization problems arise in computational procedures and sensitivity analysis. The resulting effect on solutions can be significant, with even small approximations of components of a problem translating into large…

Optimization and Control · Mathematics 2022-08-10 Johannes O. Royset

We propose the first near-optimal quantum algorithm for estimating in Euclidean norm the mean of a vector-valued random variable with finite mean and covariance. Our result aims at extending the theory of multivariate sub-Gaussian…

Quantum Physics · Physics 2022-07-20 Arjan Cornelissen , Yassine Hamoudi , Sofiene Jerbi

We outline a new approach for solving optimization problems which enforce triangle inequalities on output variables. We refer to this as metric-constrained optimization, and give several examples where problems of this form arise in machine…

Numerical Analysis · Computer Science 2018-06-06 Nate Veldt , David Gleich , Anthony Wirth , James Saunderson

Diamond quantum processors consisting of a nitrogen-vacancy (NV) centre and surrounding nuclear spins have been the key to significant advancements in room-temperature quantum computing, quantum sensing and microscopy. The optimisation of…

Quantum Physics · Physics 2020-09-24 YunHeng Chen , Sophie Stearn , Scott Vella , Andrew Horsley , Marcus W. Doherty

A quantum system that interacts with an environment generally undergoes nonunitary evolution described by a non-Markovian or Markovian master equation. In this paper, we construct the non-Markovian Redfield master equation for a quantum…

High Energy Physics - Theory · Physics 2026-01-13 Brenden Bowen , Nishant Agarwal , Archana Kamal

We develop a convex analysis approach for solving LQG optimal control problems and apply it to major-minor (MM) LQG mean-field game (MFG) systems. The approach retrieves the best response strategies for the major agent and all minor agents…

Systems and Control · Computer Science 2020-06-15 Dena Firoozi , Sebastian Jaimungal , Peter E. Caines

A system of $N$ spin-1/2 particles interacting with a thermal reservoir is used as a pedagogical example for advanced undergraduate and graduate students. We introduce and illustrate some methods, approximations, and phenomena related to…

Quantum Physics · Physics 2014-10-09 G. A. Prataviera , S. S. Mizrahi

We consider a large number $N$ of quantum particles coupled via a mean field interaction to another quantum system (reservoir). Our main result is an expansion for the averages of observables, both of the particles and of the reservoir, in…

Mathematical Physics · Physics 2018-05-09 Marco Merkli , Alireza Rafiyi

Open quantum systems are a topic of intense theoretical research. The use of master equations to model a system's evolution subject to an interaction with an external environment is one of the most successful theoretical paradigms. General…

Mean field approximation is a popular method to study the behaviour of stochastic models composed of a large number of interacting objects. When the objects are asynchronous, the mean field approximation of a population model can be…

Performance · Computer Science 2018-07-24 Nicolas Gast , Diego Latella , Mieke Massink

We give a quantum approximation scheme (i.e., $(1 + \varepsilon)$-approximation for every $\varepsilon > 0$) for the classical $k$-means clustering problem in the QRAM model with a running time that has only polylogarithmic dependence on…

Quantum Physics · Physics 2025-05-27 Ragesh Jaiswal

Realizing the potential of near-term quantum computers to solve industry-relevant constrained-optimization problems is a promising path to quantum advantage. In this work, we consider the extractive summarization constrained-optimization…

A wide class of exact master equations for a multiple qubit system can be explicitly constructed by using the corresponding exact non-Markovian quantum state diffusion equations. These exact master equations arise naturally from the quantum…

Quantum Physics · Physics 2015-03-02 Yusui Chen , J. Q. You , Ting Yu

Quantum kernel methods offer significant theoretical benefits by rendering classically inseparable features separable in quantum space. Yet, the practical application of Quantum Machine Learning (QML), currently constrained by the…

Machine Learning · Computer Science 2026-02-03 Philipp Altmann , Maximilian Mansky , Maximilian Zorn , Jonas Stein , Claudia Linnhoff-Popien

For algorithms based on interacting particle systems that admit a mean-field description, convergence analysis is often more accessible at the mean-field level. In order to transfer convergence results obtained at the mean-field level to…

Probability · Mathematics 2025-11-03 Nicolai Jurek Gerber , Franca Hoffmann , Urbain Vaes

Optimal quantum machines can be implemented by linear projective operations. In the present work a general qubit symmetrization theory is presented by investigating the close links to the qubit purification process and to the programmable…

Quantum Physics · Physics 2009-11-10 F. Sciarrino , C. Sias , M. Ricci , F. De Martini

The work is devoted to the study of quantum integrable systems associated with quantum loop algebras. The recently obtained equation for the zero temperature inhomogeneous reduced density operator is analyzed. It is demonstrated that any…

Mathematical Physics · Physics 2020-04-07 Alexander V. Razumov

The standard theoretical descriptions of the dynamics of open quantum systems rely on the assumption that the correlations with the environment can be neglected at some reference (initial) time. While being reasonable in specific instances,…

Quantum Physics · Physics 2021-11-22 Andrea Trevisan , Andrea Smirne , Nina Megier , Bassano Vacchini