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We show that quantum circuits where the initial state and all the following quantum operations can be represented by positive Wigner functions can be classically efficiently simulated. This is true both for continuous-variable as well as…

Quantum Physics · Physics 2015-06-11 A. Mari , J. Eisert

Composite bosons, here called {\it quasibosons} (e.g. mesons, excitons, etc.), occur in various physical situations. Quasibosons differ from bosons or fermions as their creation and annihilation operators obey non-standard commutation…

Mathematical Physics · Physics 2011-11-11 A. M. Gavrilik , I. I. Kachurik , Yu. A. Mishchenko

We derive exact closed-form expressions for the matrix exponential of the anti-Hermitian spin-adapted singlet double excitation fermionic operators. These expressions enable the efficient implementation of such operators within unitary…

This paper addresses the problem of computing the eigenvalues lying in the gaps of the essential spectrum of a periodic Schrodinger operator perturbed by a fast decreasing potential. We use a recently developed technique, the so called…

Spectral Theory · Mathematics 2009-11-13 Lyonell Boulton , Michael Levitin

We carry out a detailed study of the three-point fermion-photon interaction vertex at one loop order for massive fermions in reduced quantum electrodynamics. This calculation is carried out in arbitrary covariant gauges and space-time…

High Energy Physics - Phenomenology · Physics 2023-10-17 Victor Miguel Banda Guzmán , Adnan Bashir , Luis Albino , Dania Rodríguez-Tzintzun

The problem of Chern-Simons-like term induction via quantum corrections in four-dimensions is investigated in two different cases. In the first case, we consider two distinct approaches to deal with the exact fermion propagator of the…

High Energy Physics - Theory · Physics 2024-03-04 E. Passos , K. E. L. de farias , M. A. Anacleto , E. Maciel , C. A. G. Almeida

We study the {\it quasi-classical limit} of a quantum system composed of finitely many non-relativistic particles coupled to a quantized field in Nelson-type models. We prove that, as the field becomes classical and the corresponding…

Mathematical Physics · Physics 2018-08-08 Michele Correggi , Marco Falconi

The Wigner function plays a central role in QCD as a phase space object encoding correlations among quarks, antiquarks, and gluons, yet its interpretation remains subtle due to its quasiprobabilistic nature and possible negativity. Recent…

High Energy Physics - Phenomenology · Physics 2026-04-07 Chueng-Ryong Ji , Daniel W. Piasecki

We consider the problem of designing an Ansatz for the fermion-photon vertex function, using three-dimensional quantum electrodynamics as a test case. In many existing studies, restrictions have been placed on the form of the vertex Ansatz…

High Energy Physics - Theory · Physics 2009-08-11 C. J. Burden , P. C. Tjiang

Consider a 2D composites with non-overlapping equal inclusions imbedded in a host material of the normalized unit conductivity. The conductivity of inclusions takes two values $\sigma_1$ and $\sigma_2$ with the probabilities $p$ and $1-p$,…

Mathematical Physics · Physics 2017-12-18 Vladimir Mityushev

The one-dimensional effective-mass Klein-Gordon equation for the real, and non-\textrm{PT}-symmetric/non-Hermitian generalized Morse potential is solved by taking a series expansion for the wave function. The energy eigenvalues, and the…

Quantum Physics · Physics 2015-05-20 Altug Arda , Ramazan Sever

We calculate the effective electromagnetic Lagrangian up to the lowest-order corrections in the derivatives for two fermionic systems of interest in condensed matter physics in the linearized approximation of the tight-binding Hamiltonian…

High Energy Physics - Theory · Physics 2025-04-01 R. Martínez von Dossow , Luis F. Urrutia

Thought experiments about the physical nature of set theoretical counterexamples to the axiom of choice motivate the investigation of peculiar constructions, e.g. an infinite dimensional Hilbert space with a modular quantum logic. Applying…

Quantum Physics · Physics 2016-09-08 N. Brunner , K. Svozil , M. Baaz

The position operator (defined within the Schroedinger representation in the standard way) becomes meaningless when periodic boundary conditions are adopted for the wavefunction, as usual in condensed matter physics. We show how to define…

Materials Science · Physics 2009-10-30 R. Resta

An optimized Rayleigh-Schr\"{o}dinger expansion scheme of solving the functional Schr\"odinger equation with an external source is proposed to calculate the effective potential beyond the Gaussian approximation. For a scalar field theory…

High Energy Physics - Theory · Physics 2009-11-07 Wen-Fa Lu , Chul Koo Kim , Kyun Nahm

The efficient encoding of the fermionic Schr\"odinger equation as a spin system Hamiltonian is a long-term problem. I describe an encoding for the fermionic position space Schr\"odinger equation on a finite-volume periodic lattice with a…

Quantum Physics · Physics 2023-10-13 Kenneth S. McElvain

Using the operator formulation we discuss the bosonization of the two-dimensional derivative-coupling model. The fully bosonized quantum Hamiltonian is obtained by computing the composite operators as the leading terms in the Wilson short…

High Energy Physics - Theory · Physics 2008-01-14 L. V. Belvedere , A. F. Rodrigues

A conducting two-dimensional periodic composite of two anisotropic phases with anisotropic, not necessarily symmetric, conductivity tensors is considered. By finding approximate representations for the relevant operators, an approximation…

Mathematical Physics · Physics 2018-03-06 Graeme W. Milton

The effective potential theory is a physically motivated method for extending traditional plasma transport theories to stronger coupling. It is practical in the sense that it is easily incorporated within the framework of the Chapman-Enskog…

Plasma Physics · Physics 2015-06-23 Scott D. Baalrud , Kim O. Rasmussen , Jerome Daligault

We first rewrite the perturbation expansion of the time evolution operator [An Min Wang, quant-ph/0611216] in a form as concise as possible. Then we derive out the perturbation expansion of the time-dependent complete Green operator and…

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