scholarly journals QUANTUM ELECTRODYNAMICS OF RELATIVISTIC BOUND STATES WITH CUTOFFS

2004 ◽  
Vol 01 (02) ◽  
pp. 271-314 ◽  
Author(s):  
JEAN-MARIE BARBAROUX ◽  
MOUEZ DIMASSI ◽  
JEAN-CLAUDE GUILLOT
Keyword(s):  
Current Density ◽  
Coulomb Potential ◽  
Ground State ◽  
Quantum Electrodynamics ◽  
Bound States ◽  
Coupling Constants ◽  
Relativistic Electrons ◽  
Small Coupling ◽  
Electrons And Positrons ◽  
Relativistic Bound States

We consider a Hamiltonian with ultraviolet and infrared cutoffs, describing the interaction of relativistic electrons and positrons in the Coulomb potential with photons in Coulomb gauge. The interaction includes both interaction of the current density with transversal photons and the Coulomb interaction of charge density with itself. We prove that the Hamiltonian is self-adjoint and has a ground state for sufficiently small coupling constants.

scholarly journals QED in the clothed-particle representation: a fresh look at positronium properties treatment

2020 ◽  
Author(s):  
Yan Kostylenko ◽  
Adam Arslanaliev ◽  
Aleksandr V. Shebeko
Keyword(s):  
Decay Rate ◽  
Distinctive Feature ◽  
Ground State ◽  
Quantum Electrodynamics ◽  
Bound States ◽  
Analytical Expression ◽  
New Family ◽  
Electron Positron ◽  
Electrons And Positrons

We have extended our previous applications of the method of unitary clothing transformations (UCTs) in mesodynamics [1,2] to quantum electrodynamics (QED) [3,4]. An analytical expression for the QED Hamiltonian in the clothed-particle representation (CPR) has been derived. Its distinctive feature is the appearance of a new family of the Hermitian and energy independent interaction operators built up in the e^2e2-order for the clothed electrons and positrons instead the primary canonical interaction between electromagnetic and electron-positron fields. The problem of describing the bound states in QED in case of the positronium system has been considered. The first correction to the energy of the ground state of the para-positronium and its decay rate to two photons has been calculated by using the new interaction operators.

scholarly journals The relativistic bound states of Coulomb potential plus a new ring-shaped potential

2006 ◽  
Vol 55 (8) ◽  
pp. 3875
Author(s):  
Chen Chang-Yuan ◽  
Sun Dong-Sheng ◽  
Lu Fa-Lin
Keyword(s):  
Coulomb Potential ◽  
Bound States ◽  
Relativistic Bound States

scholarly journals Existence of ground state of an electron in the BDF approximation

2014 ◽  
Vol 26 (05) ◽  
pp. 1450007 ◽  
Author(s):  
Jérémy Sok
Keyword(s):  
External Field ◽  
Ground State ◽  
Quantum Electrodynamics ◽  
Adjoint Operator ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Relativistic Electrons ◽  
Relativistic Limit ◽  
Existence Of Minimizers ◽  
Dirac Sea

The Bogoliubov–Dirac–Fock (BDF) model allows us to describe relativistic electrons interacting with the Dirac sea. It can be seen as a mean-field approximation of Quantum Electrodynamics (QED) where photons are neglected. This paper treats the case of an electron together with the Dirac sea in the absence of any external field. Such a system is described by its one-body density matrix, an infinite rank, self-adjoint operator. The parameters of the model are the coupling constant α > 0 and the ultraviolet cut-off Λ > 0: we consider the subspace of squared integrable functions made of the functions whose Fourier transform vanishes outside the ball B(0, Λ). We prove the existence of minimizers of the BDF energy under the charge constraint of one electron and no external field provided that α, Λ-1 and α log(Λ) are sufficiently small. The interpretation is the following: in this regime the electron creates a polarization in the Dirac vacuum which allows it to bind. We then study the non-relativistic limit of such a system in which the speed of light tends to infinity (or equivalently α tends to zero) with αlog(Λ) fixed: after rescaling and translation the electronic solution tends to a Choquard–Pekar ground state.

scholarly journals PAULI–FIERZ MODEL WITH KATO-CLASS POTENTIALS AND EXPONENTIAL DECAYS

2010 ◽  
Vol 22 (10) ◽  
pp. 1181-1208 ◽  
Author(s):  
TAKERU HIDAKA ◽  
FUMIO HIROSHIMA
Keyword(s):  
Ground State ◽  
Quantum Electrodynamics ◽  
Bound States ◽  
The Self ◽  
Nonrelativistic Quantum ◽  
Kato Class ◽  
Symmetric Semigroup

Generalized Pauli–Fierz Hamiltonian with Kato-class potential K PF in nonrelativistic quantum electrodynamics is defined and studied by a path measure. K PF is defined as the self-adjoint generator of a strongly continuous one-parameter symmetric semigroup and it is shown that its bound states spatially exponentially decay pointwise and the ground state is unique.

scholarly journals More on complex Sachdev-Ye-Kitaev eternal wormholes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pengfei Zhang
Keyword(s):  
Black Hole ◽  
Ground State ◽  
Effective Action ◽  
Chemical Potential ◽  
Specific Charge ◽  
Zero Temperature ◽  
Small Coupling ◽  
Chemical Potentials ◽  
Quench Dynamics ◽  
Two Sides

Abstract In this work, we study a generalization of the coupled Sachdev-Ye-Kitaev (SYK) model with U(1) charge conservations. The model contains two copies of the complex SYK model at different chemical potentials, coupled by a direct hopping term. In the zero-temperature and small coupling limit with small averaged chemical potential, the ground state is an eternal wormhole connecting two sides, with a specific charge Q = 0, which is equivalent to a thermofield double state. We derive the conformal Green’s functions and determine corresponding IR parameters. At higher chemical potential, the system transit into the black hole phase. We further derive the Schwarzian effective action and study its quench dynamics. Finally, we compare numerical results with the analytical predictions.

scholarly journals Dynamical Symmetries of the H Atom, One of the Most Important Tools of Modern Physics: SO(4) to SO(4,2), Background, Theory, and Use in Calculating Radiative Shifts

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1323 ◽  
Author(s):  
G. Jordan Maclay
Keyword(s):  
Hydrogen Atom ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Bound States ◽  
Integrated Treatment ◽  
Invariance Group ◽  
Elementary Particle Physics ◽  
Background Theory ◽  
Modern Physics ◽  
History Of

Understanding the hydrogen atom has been at the heart of modern physics. Exploring the symmetry of the most fundamental two body system has led to advances in atomic physics, quantum mechanics, quantum electrodynamics, and elementary particle physics. In this pedagogic review, we present an integrated treatment of the symmetries of the Schrodinger hydrogen atom, including the classical atom, the SO(4) degeneracy group, the non-invariance group or spectrum generating group SO(4,1), and the expanded group SO(4,2). After giving a brief history of these discoveries, most of which took place from 1935–1975, we focus on the physics of the hydrogen atom, providing a background discussion of the symmetries, providing explicit expressions for all of the manifestly Hermitian generators in terms of position and momenta operators in a Cartesian space, explaining the action of the generators on the basis states, and giving a unified treatment of the bound and continuum states in terms of eigenfunctions that have the same quantum numbers as the ordinary bound states. We present some new results from SO(4,2) group theory that are useful in a practical application, the computation of the first order Lamb shift in the hydrogen atom. By using SO(4,2) methods, we are able to obtain a generating function for the radiative shift for all levels. Students, non-experts, and the new generation of scientists may find the clearer, integrated presentation of the symmetries of the hydrogen atom helpful and illuminating. Experts will find new perspectives, even some surprises.

scholarly journals On relativistic entanglement and localization of particles and on their comparison with the nonrelativistic theory

2014 ◽  
Vol 29 (29) ◽  
pp. 1450163 ◽  
Author(s):  
Horace W. Crater ◽  
Luca Lusanna
Keyword(s):  
Bound States ◽  
Clock Synchronization ◽  
Center Of Mass ◽  
Particle Beams ◽  
Open Problems ◽  
Inertial Frames ◽  
Classical Trajectories ◽  
Particle Localization ◽  
Relativistic Bound States ◽  
Classical And Quantum Mechanics

We make a critical comparison of relativistic and nonrelativistic classical and quantum mechanics of particles in inertial frames as well of the open problems in particle localization at both levels. The solution of the problems of the relativistic center-of-mass, of the clock synchronization convention needed to define relativistic 3-spaces and of the elimination of the relative times in the relativistic bound states leads to a description with a decoupled nonlocal (nonmeasurable) relativistic center-of-mass and with only relative variables for the particles (single particle subsystems do not exist). We analyze the implications for entanglement of this relativistic spatial nonseparability not existing in nonrelativistic entanglement. Then, we try to reconcile the two visions showing that also at the nonrelativistic level in real experiments only relative variables are measured with their directions determined by the effective mean classical trajectories of particle beams present in the experiment. The existing results about the nonrelativistic and relativistic localization of particles and atoms support the view that detectors only identify effective particles following this type of trajectories: these objects are the phenomenological emergent aspect of the notion of particle defined by means of the Fock spaces of quantum field theory.

scholarly journals Simulation of ultra-relativistic electrons and positrons channeling in crystals with MBN Explorer

2013 ◽  
Vol 252 ◽  
pp. 404-418 ◽  
Author(s):  
Gennady B. Sushko ◽  
Victor G. Bezchastnov ◽  
Ilia A. Solovʼyov ◽  
Andrei V. Korol ◽  
Walter Greiner ◽  
...  
Keyword(s):  
Relativistic Electrons ◽  
Electrons And Positrons
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