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The extended Bose-Hubbard model for a double-well potential with pair tunneling is studied through both exact diagonalization and mean field theory (MFT). When pair tunneling is strong enough, the ground state wavefunction predicted by the…

Quantum Gases · Physics 2015-05-05 Qizhong Zhu , Qi Zhang , Biao Wu

We obtain an exact solution of the 1D Dirac equation for a square well potential of depth greater then twice the particle's mass. The energy spectrum formula in the Klein zone is surprisingly very simple and independent of the depth of the…

Quantum Physics · Physics 2015-05-13 A. D. Alhaidari

We study cusped Wilson line operators in the Abelian Higgs model in $ d = 4 - \epsilon $ at large external charges. Using a double-scaling limit $ Q \to \infty $, $ \epsilon \to 0 $ with $ Q\epsilon $ fixed, we develop a semiclassical…

High Energy Physics - Theory · Physics 2026-04-20 Jahmall Bersini , Domenico Orlando , Susanne Reffert , Jesse Woods

The spontaneous switching of a quantum particle between the wells of a double-well potential is a phenomenon of general interest to physics and chemistry. It was broadly believed that the switching rate decreases steadily with the size of…

Quantum Physics · Physics 2025-10-14 Qile Su , Rodrigo G. Cortiñas , Jayameenakshi Venkatraman , Shruti Puri

We study the problem of minimizing or maximizing the fundamental spectral gap of Schr\"odinger operators on metric graphs with either a convex potential or a ``single-well'' potential on an appropriate specified subset. (In the case of…

Spectral Theory · Mathematics 2024-01-10 Mohammed Ahrami , Zakaria El Allali , Evans M Harrell , James B. Kennedy

We derive a new Sequential-Monte-Carlo-based algorithm to estimate the capacity of two-dimensional channel models. The focus is on computing the noiseless capacity of the 2-D one-infinity run-length limited constrained channel, but the…

Information Theory · Computer Science 2014-08-12 Christian A. Naesseth , Fredrik Lindsten , Thomas B. Schön

We establish accurate eigenvalue asymptotics and, as a by-product, sharp estimates of the splitting between two consecutive eigenvalues, for the Dirichlet magnetic Laplacian with a non-uniform magnetic field having a jump discontinuity…

Mathematical Physics · Physics 2024-03-13 Wafaa Assaad , Bernard Helffer , Ayman Kachmar

The performance of quantum annealing for combinatorial optimization is fundamentally limited by the minimum energy gap $\Delta$ encountered at quantum phase transitions. We investigate the scaling of $\Delta$ with system size $N$ for two…

Disordered Systems and Neural Networks · Physics 2026-05-22 L. Brodoloni , G. E. Astrakharchik , S. Giorgini , S. Pilati

We use the discrete approach to solve the Schr\"odinger as well as the Bloch equations for a free particle and the quantum gas of free particles embedded in an infinite quantum well with the finite width. We obtain the expressions of energy…

Quantum Physics · Physics 2023-03-16 Dušan Popov

Shallow one-dimensional double well potentials appear in atomic and molecular physics and other fields. Unlike the "deep" wells of macroscopic quantum coherent systems, shallow double wells need not present low-lying two-level systems. We…

We perform a systematic WKB expansion to all orders for a one-dimensional system with potential $V(x)=U_0/\cos^2{(\alpha x)}$. We are able to sum the series to the exact energy spectrum. Then we show that at any finite order the error of…

Quantum Physics · Physics 2016-09-08 Marko Robnik , Luca Salasnich

This paper proposes a universal microscopic model for the shallow confinement regime of single-electron tunneling devices. We consider particle escape from a quantum well generically emerging as a bifurcation in a smooth electrostatic…

Mesoscale and Nanoscale Physics · Physics 2025-04-11 Austris Akmentinsh , Niels Ubbelohde , Vyacheslavs Kashcheyevs

We introduce a numerical method to obtain approximate eigenvalues for some problems of Sturm-Liouville type. As an application, we consider an infinite square well in one dimension in which the mass is a function of the position. Two…

Quantum Physics · Physics 2014-02-24 Juan Jose Alvarez , Manuel Gadella , Luis Pedro Lara

We consider time-dependent Schroedinger equations in one dimension with double well potential and an external nonlinear perturbation. If the initial state belongs to the eigenspace spanned by the eigenvectors associated to the two lowest…

Mathematical Physics · Physics 2007-05-23 Andrea Sacchetti

We prove that the singularities of a potential in the two and three dimensional Schr\"odinger equation are the same as the singularities of the Born approximation (Diffraction Tomography), obtained from backscattering inverse data, with an…

Analysis of PDEs · Mathematics 2009-02-19 Juan Manuel Reyes , Alberto Ruiz

We consider a non relativistic charged particle in a 1-dimensional infinite square potential well. This quantum system is subjected to a control, which is a uniform (in space) time depending electric field. It is represented by a complex…

Analysis of PDEs · Mathematics 2008-01-11 Karine Beauchard , Mazyar Mirrahimi

The evolution of the quantum wave packet describing an atom trapped in the surface-tip junction of the scanning tunneling microscope is investigated by using the time-dependent Schroedinger equation, and by a quasi-classical Hamiltonian…

Quantum Physics · Physics 2008-02-21 M. Grigorescu

An $\hbar$-expansion is presented for the ensemble-averaged spectral function of noninteracting matter waves in random potentials. We obtain the leading quantum corrections to the deep classical limit at high energies by the Wigner-Weyl…

Quantum Gases · Physics 2015-06-01 Martin-Isbjörn Trappe , Dominique Delande , Cord A. Müller

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

We consider the two-matrix model with potentials whose derivative are arbitrary rational function of fixed pole structure and the support of the spectra of the matrices are union of intervals (hard-edges). We derive an explicit formula for…

High Energy Physics - Theory · Physics 2009-11-11 M. Bertola
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