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We introduce a semiclassical quantization method which is based on a stroboscopic description of the classical and the quantum flows. We show that this approach emerges naturally when one is interested in extracting the energy spectrum…

Chaotic Dynamics · Physics 2007-05-23 Bruno Eckhardt , Uzy Smilansky

The measurements of quasi-periodic oscillations (QPOs) provide a quite powerful tool to test the nature of astrophysical black hole candidates in the strong gravitational field regime. In this paper, we use QPOs within the relativistic…

General Relativity and Quantum Cosmology · Physics 2021-12-08 Xin Jiang , Peng Wang , Houwen Wu , Haitang Yang

Differential equations on spaces of operators are very little developed in Mathematics, being in general very challenging. Here, we study a novel system of such (non-linear) differential equations. We show it has a unique solution for all…

Mathematical Physics · Physics 2025-01-22 Jean-Bernard Bru , Nathan Metraud

We investigate a quantization problem which asks for the construction of an algebra for relative elliptic problems of pseudodifferential type associated to smooth embeddings. Specifically, we study the problem for embeddings in the category…

Differential Geometry · Mathematics 2017-10-09 Karsten Bohlen , René Schulz

We use nonstandard analysis to formulate quantum mechanics in hyperfinite-dimensional spaces. Self-adjoint operators on hyperfinite-dimensional spaces have complete eigensets, and bound states and continuum states of a Hamiltonian can thus…

Mathematical Physics · Physics 2007-05-23 Andreas Raab

The Quantum Approximate Optimization Algorithm (QAOA) requires considered optimization problems to be translated into a compatible format. A popular transformation step in this pipeline involves the quadratization of higher-order binary…

Quantum Physics · Physics 2025-11-26 Damian Rovara , Lukas Burgholzer , Robert Wille

The quantum approximate optimization algorithm (QAOA) transforms a simple many-qubit wavefunction into one which encodes a solution to a difficult classical optimization problem. It does this by optimizing the schedule according to which…

Quantum Physics · Physics 2022-06-29 Yunlong Yu , Chenfeng Cao , Carter Dewey , Xiang-Bin Wang , Nic Shannon , Robert Joynt

Operator product expansions (OPEs) in quantum field theory (QFT) provide an asymptotic relation between products of local fields defined at points $x_1, \dots, x_n$ and local fields at point $y$ in the limit $x_1, \dots, x_n \to y$. They…

High Energy Physics - Theory · Physics 2023-12-05 Stefan Hollands , Robert M. Wald

This paper concentrates on the quantitative homogenization of higher-order elliptic systems with almost-periodic coefficients in bounded Lipschitz domains. For coefficients which are almost-periodic in the sense of H. Weyl, we establish…

Analysis of PDEs · Mathematics 2020-01-30 Yao Xu , Weisheng Niu

We show that in the semiclassical limit, classically chaotic systems have universal spectral statistics. Concentrating on short-time statistics, we identify the pairs of classical periodic orbits determining the small-$\tau$ behavior of the…

Chaotic Dynamics · Physics 2007-05-23 Sebastian Müller

We investigate the asymptotic behavior of Halpern-type iterations applied to quasi-nonexpansive operators arising in best approximation problems over the intersection of finitely many closed convex sets in $\mathbb{R}^n$. Assuming a local…

Optimization and Control · Mathematics 2026-05-29 Pablo Barros , Vincent Guigues , Roger Behling , Luiz-Rafael Santos

We employ the operational quasiprobability (OQ) as a work distribution, which reproduces the Jarzynski equality and yields the average work consistent with the classical definition. The OQ distribution can be experimentally implemented…

Quantum Physics · Physics 2025-10-07 Jeongwoo Jae , Junghee Ryu , Hoon Ryu

Introducing an H-Hopf algebroid structure into U_{q,p}(\widedhat{sl}_2), we investigate the vertex operators of the elliptic quantum group U_{q,p}(\widedhat{sl}_2) defined as intertwining operators of infinite dimensional…

Quantum Algebra · Mathematics 2008-11-26 Hitoshi Konno

Quantum process tomography (QPT) plays a central role in characterizing quantum gates and circuits, diagnosing quantum devices, calibrating hardware, and supporting quantum error correction. However, conventional QPT methods face challenges…

Quantum Physics · Physics 2026-02-06 Huynh Le Dan Linh , Vu Tuan Hai , Le Bin Ho

In this paper we work with the approximation of unitary groups of operators of the form $e^{-itH}$ where $H\in\mathscr{L}(\mathcal{H})$ is the Hamiltonian of a given quantum dynamical system modeled in the discretizable Hilbert space…

Functional Analysis · Mathematics 2011-03-29 Fredy Vides

Consider an elliptic self-adjoint pseudodifferential operator $A$ acting on $m$-columns of half-densities on a closed manifold $M$, whose principal symbol is assumed to have simple eigenvalues. Relying on a basis of pseudodifferential…

Analysis of PDEs · Mathematics 2022-01-12 Matteo Capoferri

High frequency (millisecond) quasi-periodic oscillations (HF QPOs) are observed in the X-ray power-density spectra of several microquasars and low mass X-ray binaries. Two distinct QPO peaks, so-called twin peak QPOs, are often detected…

High Energy Astrophysical Phenomena · Physics 2015-09-02 Pavel Bakala , Kateřina Goluchová , Gabriel Török , Eva Šrámková , Marek A. Abramowicz , Frederic H. Vincent , Grzegorz P. Mazur

This paper explores operators with countable, continuous, and hybrid spectra, focusing on both finite dimensional and infinite dimensional cases, particularly in non-Hermitian systems. For finite dimensional operators, a novel concept of…

Functional Analysis · Mathematics 2024-11-20 Shih-Yu Chang

Some of the most remarkable tilings and discrete quasiperiodic sets used in quasicrystal physics can be obtained by using strip projection method in a superspace of dimension four, five or six, and the projection of a unit hypercube as a…

Mathematical Physics · Physics 2009-11-11 Nicolae Cotfas

The Quantum Approximate Optimization Algorithm (QAOA) is a promising candidate algorithm for demonstrating quantum advantage in optimization using near-term quantum computers. However, QAOA has high requirements on gate fidelity due to the…

Quantum Physics · Physics 2023-03-20 Xiaoyuan Liu , Ruslan Shaydulin , Ilya Safro