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Current quantum computing devices have different strengths and weaknesses depending on their architectures. This means that flexible approaches to circuit design are necessary. We address this task by introducing a novel space-efficient…

Given a statistical ensemble of quantum states, the corresponding Page curve quantifies the average entanglement entropy associated with each possible spatial bipartition of the system. In this work, we study a natural extension in the…

High Energy Physics - Theory · Physics 2022-08-31 Sara Murciano , Pasquale Calabrese , Lorenzo Piroli

We demonstrate how resonances in a quantum graph consisting of a compact core and semi-infinite leads can be identified from the eigenvalue behavior of the cut-off system.

Quantum Physics · Physics 2026-01-26 Pavel Exner , Jiří Lipovský , Jan Pekař

We investigate quantum graphs with infinitely many vertices and edges without the common restriction on the geometry of the underlying metric graph that there is a positive lower bound on the lengths of its edges. Our central result is a…

Mathematical Physics · Physics 2018-10-30 Pavel Exner , Aleksey Kostenko , Mark Malamud , Hagen Neidhardt

One of the most celebrated accomplishments of modern physics is the description of fundamental principles of nature in the language of geometry. As the motion of celestial bodies is governed by the geometry of spacetime, the motion of…

Mesoscale and Nanoscale Physics · Physics 2024-09-23 Tianyu Liu , Xiao-Bin Qiang , Hai-Zhou Lu , X. C. Xie

On a finite connected metric graph, we establish upper bounds for the eigenvalues of the Laplacian. These bounds depend on the length, the Betti number, and the number of pendant vertices. For trees, these estimates are sharp. We also…

Spectral Theory · Mathematics 2016-09-26 Sinan Ariturk

The interplay between thermodynamics, general relativity and quantum mechanics has long intrigued researchers. Recently, important advances have been obtained in thermodynamics, mainly regarding its application to the quantum domain through…

General Relativity and Quantum Cosmology · Physics 2025-02-07 Marcos L. W. Basso , Jonas Maziero , Lucas Chibebe Céleri

We discuss a method by which quantum fluctuations can be included in microscopic transport models based on wave packets that are not energy eigenstates. By including the next-to-leading order term in the cumulant expansion of the…

Nuclear Theory · Physics 2009-10-30 A. Ohnishi , J. Randrup

We study the multi-periodic oscillations in the spontaneous emission rate of an atom in a medium with refractive index n sandwiched between two parallel mirrors. The oscillations are not obvious in the analytical formula for the rate…

Quantum Physics · Physics 2007-05-23 H. J. Zhao , M. L. Du

We have carried out first-principles calculations on electronic properties of graphene quantum dots embedded in hexagonal boron nitride monolayer sheets. The calculations with density functional theory show that the band gaps of quantum…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Junwen Li , Vivek B. Shenoy

In this letter we study the weak-convergence properties of random variables generated by unsharp quantum measurements. More precisely, for a sequence of random variables generated by repeated unsharp quantum measurements, we study the limit…

Quantum Physics · Physics 2020-08-12 Aleksandra Dimić , Borivoje Dakić

We consider the motion by mean curvature of an $n$-dimensional graph over a time-dependent domain in $\mathbb{R}^n$, intersecting $\mathbb{R}^n$ at a constant angle. In the general case, we prove local existence for the corresponding…

Analysis of PDEs · Mathematics 2008-12-10 Alexandre Freire

We initiate the study of approximate quantum fractional revival in graphs, a generalization of pretty good quantum state transfer in graphs. We give a complete characterization of approximate fractional revival in a graph in terms of the…

Combinatorics · Mathematics 2020-05-04 Ada Chan , Whitney Drazen , Or Eisenberg , Mark Kempton , Gabor Lippner

Decay of bound states due to coupling with free particle states is a general phenomenon occurring at energy scales from MeV in nuclear physics to peV in ultracold atomic gases. Such a coupling gives rise to Fano-Feshbach resonances (FFR)…

We demonstrate that quantum correlations can emerge from the statistical correlations of random discrete models, without an a priori assumption that the random models are quantum mechanical in nature, that is without considering…

Disordered Systems and Neural Networks · Physics 2023-05-05 Ioannis Kleftogiannis , Ilias Amanatidis

We propose an improved scheme of perturbation theory based on our exact solution [An Min Wang, quant-ph/0611216] in general quantum systems independent of time. Our elementary start-point is to introduce the perturbing parameter as late as…

Quantum Physics · Physics 2007-05-23 An Min Wang

Many computational problems are unchanged under some symmetry operation. In classical machine learning, this can be reflected with the layer structure of the neural network. In quantum machine learning, the ansatz can be tuned to correspond…

The explicit solution to the spectral problem of quantum graphs is used to obtain the exact distributions of several spectral statistics, such as the oscillations of the quantum momentum eigenvalues around the average, $\delta…

Quantum Physics · Physics 2007-05-23 Yu. Dabaghian

An initial local excitation in a confined quantum system evolves exploring the whole system, returning to the initial position as a mesoscopic echo at the Heisenberg time. We consider a two weakly coupled spin chains, a spin ladder, where…

We investigate the equidistribution of the eigenfunctions on quantum graphs in the high-energy limit. Our main result is an estimate of the deviations from equidistribution for large well-connected graphs. We use an exact field-theoretic…

Chaotic Dynamics · Physics 2009-11-13 S. Gnutzmann , J. P. Keating , F. Piotet