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Traditional computations of the dark matter (DM) relic abundance, for models where attractive self-interactions are mediated by light force-carriers and bound states exist, rely on the solution of a coupled system of classical on-shell…

High Energy Physics - Phenomenology · Physics 2018-12-26 Tobias Binder , Laura Covi , Kyohei Mukaida

We generalize the notion of joint measurability to continuous variable systems by extending a recently introduced compression algorithm of quantum measurements to this realm. The extension results in a property that asks for the minimal…

Quantum Physics · Physics 2026-03-03 Pauli Jokinen , Sophie Egelhaaf , Juha-Pekka Pellonpää , Roope Uola

Entanglement in multipartite quantum systems is much more elusive than its bipartite counterpart. In recent past the usefulness of multipartite entangled states in several information theoretic tasks have been demonstrated. Being a…

Quantum Physics · Physics 2018-02-02 Sutapa Saha , Some Sankar Bhattacharya , Arup Roy , Amit Mukherjee , Ramij Rahaman

A major problem in system identification is the incorporation of prior knowledge about the physical properties of the given system, such as stability, positivity and passivity. In this paper, we present first steps towards tackling this…

Optimization and Control · Mathematics 2024-04-15 Brayan M. Shali , Henk J. van Waarde

We prove the existence of a sequence of commutative diagrams generalizing existing results on the cohomology of the Borel-Serre boundary and well-rounded retract to the context of the well-tempered complex. Our main theorem provides a…

Number Theory · Mathematics 2025-10-21 Dylan Galt , Mark McConnell

We study maximal representations of nonnegative sesquilinear forms in real or complex Hilbert spaces, that are not necessarily closed or even closable. We associate positive self-adjoint operators with such forms, in a sense similar to…

Functional Analysis · Mathematics 2025-05-15 Zoltán Sebestyén , Zsigmond Tarcsay

Spectral properties of random Schr\"odinger operators are encoded in the average of products of Greens functions. For probability distributions with enough finite moments, the supersymmetric approach offers a useful dual representation.…

Mathematical Physics · Physics 2021-11-17 Margherita Disertori , Mareike Lager

Purification is a tool that allows to represent mixed quantum states as pure states on enlarged Hilbert spaces. A purification of a given state is not unique and its entanglement strongly depends on the particular choice made. Moreover, in…

Strongly Correlated Electrons · Physics 2019-01-08 Johannes Hauschild , Eyal Leviatan , Jens H. Bardarson , Ehud Altman , Michael P. Zaletel , Frank Pollmann

We argue that Hopf-algebra deformations of symmetries -- as encountered in non-commutative models of quantum spacetime -- carry an intrinsic content of $operator$ $entanglement$ that is enforced by the coproduct-defined notion of composite…

Quantum Physics · Physics 2026-01-01 Michele Arzano , Goffredo Chirco

This article presents a concrete mathematical framework for the generation of entangled quantum states from classical stochastic processes. We demonstrate that any density operator $\rho_{AB}$ of a composite system can be derived from the…

Quantum Physics · Physics 2026-01-27 Andrei Khrennikov

We investigate optimal separable approximations (decompositions) of states rho of bipartite quantum systems A and B of arbitrary dimensions MxN following the lines of Ref. [M. Lewenstein and A. Sanpera, Phys. Rev. Lett. 80, 2261 (1998)].…

Quantum Physics · Physics 2016-09-08 S. Karnas , M. Lewenstein

The spontaneous disentanglement hypothesis is motivated by some outstanding issues in standard quantum mechanics, including the problem of quantum measurement. The current study compares between some possible methods that can be used to…

Quantum Physics · Physics 2026-02-10 Eyal Buks

Entanglement in quantum many-body systems is the key concept for future technology and science, opening up a possibility to explore uncharted realms in an enormously large Hilbert space. The hybrid quantum-classical algorithms have been…

Strongly Correlated Electrons · Physics 2023-08-02 Donggyu Kim , Pureum Noh , Hyun-Yong Lee , Eun-Gook Moon

Using the mixed space representation (t,p) in the context of scalar field theories, we prove in a simple manner that the Feynman graphs at finite temperature are related to the corresponding zero temperature diagrams through a simple…

High Energy Physics - Theory · Physics 2008-11-26 Fernando T. Brandt , Ashok Das , Olivier Espinosa , Josif Frenkel , Silvana Perez

Magic, capturing the deviation of a quantum state from the stabilizer formalism, is a key resource underpinning the quantum advantage. The recently introduced stabilizer R\'enyi entropy (SRE) offers a tractable measure of magic, avoiding…

Quantum Physics · Physics 2025-08-06 Lei-Yi-Nan Liu , Su Yi , Jian Cui

An example is given of an interaction that produces an infinite amount of entanglement in an infinitely short time, but only a finite amount in longer times. The interaction arises from a standard Kerr nonlinearity and a 50/50 beamsplitter,…

Quantum Physics · Physics 2009-11-10 S. J. van Enk

We discuss the numerical solution methods available when solving for the steady-state density matrix of a time-independent open quantum optical system, where the system operators are expressed in a suitable basis representation as sparse…

Quantum Physics · Physics 2015-04-28 P. D. Nation

Interrelation of the Coleman's representabilty theory for 1-density operators and abstract algebraic form of the Hohenberg-Kohn theorem is studied in detail. Convenient realization of the Hohenberg-Kohn set of classes of 1-electron…

Chemical Physics · Physics 2015-06-26 A. I. Panin

We develop a novel numerical scheme for the simulation of dissipative quantum dynamics following from two-body Lindblad master equations. All defining continuum properties of the Lindblad dynamics, hermiticity, positivity and in particular…

Computational Physics · Physics 2021-02-24 Oskar Ålund , Yukinao Akamatsu , Fredrik Laurén , Takahiro Miura , Jan Nordström , Alexander Rothkopf

We introduce the Gaussian quantum operator representation, using the most general multi-mode Gaussian operator basis. The representation unifies and substantially extends existing phase-space representations of density matrices for Bose…

Quantum Physics · Physics 2009-11-10 Joel F. Corney , Peter D. Drummond
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