Equal-Time Terms in Perturbation Theory and Convolutions of Tempered Distributions

1971 ◽  
Vol 4 (6) ◽  
pp. 1681-1689
Author(s):  
Paul Otterson
Keyword(s):  
Perturbation Theory ◽  
Tempered Distributions ◽  
Equal Time

scholarly journals Hamiltonian approach to QCD in Coulomb gauge: Perturbative treatment of the quark sector

2015 ◽  
Vol 30 (17) ◽  
pp. 1550100 ◽  
Author(s):  
Davide R. Campagnari ◽  
Hugo Reinhardt
Keyword(s):  
Perturbation Theory ◽  
Quantum Chromodynamics ◽  
Quark Propagator ◽  
Functional Integral ◽  
Coulomb Gauge ◽  
Hamiltonian Approach ◽  
Equal Time ◽  
Quark Sector ◽  
Schrödinger Perturbation ◽  
Perturbative Treatment

We study the static gluon and quark propagator of the Hamiltonian approach to quantum chromodynamics in Coulomb gauge in one-loop Rayleigh–Schrödinger perturbation theory. We show that the results agree with the equal-time limit of the four-dimensional propagators evaluated in the functional integral (Lagrangian) approach.

Equal-time behaviour of current commutators in perturbation theory

1969 ◽  
Vol 26 (1-2) ◽  
pp. 181-189
Author(s):  
F. Kaschluhn ◽  
E. Wieczorek ◽  
W. Zoellner
Keyword(s):  
Perturbation Theory ◽  
Time Behaviour ◽  
Equal Time

scholarly journals Nonperturbative matching between equal-time and lightcone quantization

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
A. Liam Fitzpatrick ◽  
Emanuel Katz ◽  
Matthew T. Walters
Keyword(s):  
Perturbation Theory ◽  
Equal Time ◽  
Mass Gap ◽  
Physical Quantities ◽  
Borel Resummation

Abstract We investigate the nonperturbative relation between lightcone (LC) and standard equal-time (ET) quantization in the context of λϕ4 theory in d = 2. We discuss the perturbative matching between bare parameters and the failure of its naive nonperturbative extension. We argue that they are nevertheless the same theory nonperturbatively, and that furthermore the nonperturbative map between bare parameters can be extracted from ET perturbation theory via Borel resummation of the mass gap. We test this map by using it to compare physical quantities computed using numerical Hamiltonian truncation methods in ET and LC.

Singular equal-time behaviour of current commutators in perturbation theory

1968 ◽  
Vol 8 (1) ◽  
pp. 84-94 ◽  
Author(s):  
F. Kaschluhn ◽  
E. Wieczorek ◽  
W. Zoellner
Keyword(s):  
Perturbation Theory ◽  
Time Behaviour ◽  
Equal Time

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

Energy, Information, and Superluminal Speed in Quantum Electrodynamics

2020 ◽  
pp. 27-33
Author(s):  
Boris A. Veklenko
Keyword(s):  
Electromagnetic Field ◽  
Perturbation Theory ◽  
Quantum Electrodynamics ◽  
Excited Atom ◽  
Standard Quantum ◽  
Energy Information

Without using the perturbation theory, the article demonstrates a possibility of superluminal information-carrying signals in standard quantum electrodynamics using the example of scattering of quantum electromagnetic field by an excited atom.

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