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Given a set of $n$ distinct real numbers, our goal is to form a symmetric, unreduced, tridiagonal, matrix with those numbers as eigenvalues. We give an algorithm which is a stable implementation of a naive algorithm forming the…

Numerical Analysis · Mathematics 2023-11-07 Luca Dieci , Alessandro Pugliese

We attempt to construct the full equations of motion for the Neveu-Schwarz and the Ramond sectors of the heterotic string field theory. Although they are non-polynomial also in the Ramond string field $\Psi$, we can construct them order by…

High Energy Physics - Theory · Physics 2014-05-07 Hiroshi Kunitomo

Squeezed Schr\"odinger cat states are a valuable resource for quantum error correction and quantum computing. In this paper, we investigate the gate for generating such states in the optical regime. Our scheme is based on the entanglement…

Quantum Physics · Physics 2025-04-28 A. V. Baeva , A. S. Losev , I. V. Sokolov

This paper presents an algorithmic method for generating random orthogonal matrices \(A\) that satisfy the property \(A^t S A = S\), where \(S\) is a fixed real invertible symmetric or skew-symmetric matrix. This method is significant as it…

Numerical Analysis · Mathematics 2024-12-19 Ali Saraeb

The paper is a continuation of the study started in \cite{Yorzh1}. Schrodinger operators on finite compact metric graphs are considered under the assumption that the matching conditions at the graph vertices are of $\delta$ type. Either an…

Mathematical Physics · Physics 2014-04-02 Yulia Ershova , Alexander V. Kiselev

We present a package for FeynRules which derives the Feynman rules for the Standard Model Effective Field Theory up to dimension-six using the background field method for gauge fixing. The package includes operators which shift the kinetic…

High Energy Physics - Phenomenology · Physics 2021-03-17 T. Corbett

An algorithm and a computer program in Fortran 95 are presented which enumerate the Hugenholtz diagram representation of the many-body perturbation series for the ground state energy with a two-body interaction. The output is in a form…

Computational Physics · Physics 2009-11-10 P. D. Stevenson

We develop a quantum algorithm for solving high-dimensional fractional Poisson equations. By applying the Caffarelli-Silvestre extension, the $d$-dimensional fractional equation is reformulated as a local partial differential equation in…

Numerical Analysis · Mathematics 2025-05-06 Shi Jin , Nana Liu , Yue Yu

In this contribution the matrix element generator AMEGIC++ will be presented. It automatically generates Feynman diagrams, helicity amplitudes, and suitable phase space mappings for processes involving multi-particle final states within the…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. Gleisberg , S. Hoeche , F. Krauss , A. Schaelicke , S. Schumann , J. Winter , G. Soff

We give an algorithm for obtaining expansions of massive two-loop Feynman graphs in powers of the external momentum around a finite, nonzero value of the momentum. This is based on our general two-loop formalism to reduce massive two-loop…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. Ghinculov , Y. P. Yao

The local phase-invariance of the momentum-space Schr\"odinger equation for free-particle has been used to construct quantum kinematics that describes a motion of the particle in external U(1) background gauge field. The gauge structure…

Quantum Physics · Physics 2010-06-10 Boyan Obreshkov

We consider Schr\"odinger operators on sparse graphs. The geometric definition of sparseness turn out to be equivalent to a functional inequality for the Laplacian. In consequence, sparseness has in turn strong spectral and functional…

Spectral Theory · Mathematics 2014-02-07 Michel Bonnefont , Sylvain Golenia , Matthias Keller

The finite difference time domain (FDTD) algorithm and Green function algorithm are implemented into the numerical simulation of electromagnetic scattering by ordinary objects in Schwarzschild space-time. FDTD method in curved space-time is…

Computational Physics · Physics 2018-04-13 Shouqing Jia

In this article we obtain asymptotic formulas for the Bloch eigenvalues of the operator generated by a system of Schrodinger equations with periodic PT-symmetric complex-valued coefficients. Then using these formulas we classify the…

Spectral Theory · Mathematics 2021-10-13 O. A. Veliev

We give a Python program that is capable to compute and print all the distinct trivalent 2-stratifold graphs up to $N$ white vertices with trivial fundamental group. Our algorithm uses the three basic operations to construct new graphs from…

General Topology · Mathematics 2020-11-30 Myriam Hernández-Ketchul , Jesús Rodríguez-Viorato

We analyze perturbative aspects of gauged matrix models, including those where classically the gauge symmetry is partially broken. Ghost fields play a crucial role in the Feynman rules for these vacua. We use this formalism to elucidate the…

High Energy Physics - Theory · Physics 2009-11-07 Robbert Dijkgraaf , Sergei Gukov , Vladimir A. Kazakov , Cumrun Vafa

We point out an enhancement of the pair production rate of charged fermions in a strong electric field in the presence of time dependent classical axion-like background field, which we call axion assisted Schwinger effect. While the…

High Energy Physics - Phenomenology · Physics 2021-05-19 Valerie Domcke , Yohei Ema , Kyohei Mukaida

Starting from degree N solutions of a time dependent Schroedinger-like equation for classical orthogonal polynomials, a linear matrix equation describing perturbations around the N zeros of the polynomial is derived. The matrix has…

Classical Analysis and ODEs · Mathematics 2015-06-23 Ryu Sasaki

We prove the bispectrality of some class of matrix Schr\"odinger operators with polynomial potentials that satisfy a second-order matrix autonomous differential equation. The physical equation is constructed using the formal theory of the…

Spectral Theory · Mathematics 2024-02-02 Brian D. Vasquez Campos

A method of Feynman diagrams summation, based on using Schwinger-Dyson equations and Ward identities, is verified by calculating some four-loop diagrams in N=1 supersymmetric electrodynamics, regularized by higher derivatives. In…

High Energy Physics - Theory · Physics 2009-11-11 A. B. Pimenov , K. V. Stepanyantz