The self-energy problem in ground state and phonon calculation of quantum solids

1976 ◽  
Vol 23 (3-4) ◽  
pp. 319-334 ◽  
Author(s):  
H. Bolterauer ◽  
P. Gillessen
Keyword(s):  
Ground State ◽  
The Self ◽  
Quantum Solids ◽  
Energy Problem ◽  
Self Energy ◽  
Phonon Calculation

scholarly journals A New Attempt on the Self-Energy Problem of the Photon

1952 ◽  
Vol 8 (3) ◽  
pp. 265-279 ◽  
Author(s):  
O. Hara ◽  
H. Shimazu
Keyword(s):  
The Self ◽  
Energy Problem ◽  
Self Energy

An INDO MO Study on the Ground State and the Cationic States of Cyclopentadienyl Nickel Nitrosyl

1981 ◽  
Vol 36 (12) ◽  
pp. 1361-1366 ◽  
Author(s):  
Michael C. Böhm
Keyword(s):  
Perturbation Theory ◽  
Electronic Structure ◽  
Ground State ◽  
The Self ◽  
Many Body ◽  
Self Energy ◽  
Cyclopentadienyl Ligand ◽  
Energy Part ◽  
Correct Sequence ◽  
Many Body Perturbation Theory

The electronic structure of cyclopentadienyl nickel nitrosyl (1) in the ground state as well as the cationic states of 1 are investigated by means of a semiempirical INDO Hamiltonian and many body perturbation theory. It is demonstrated that the nature of the NiNO coupling is largely covalent while the interaction between the 3d center and the cyclopentadienyl ligand is predominantly of ionic type. The ground state MO sequence of the Ni 3d orbitals is 4e2(3dx²-y²/3dxy) below 7e1(3dXz/3dyz) and 15a1(3dz2). The sequence of the ionization potentials is 8e1 (Cp - π) < 15a1<4e2<7e1. The ionization energies have been determined by means of the Green’s function formalism; the self-energy part has been calculated by a second order and a renormalized approximation. Both procedures predict the correct sequence of ionization events.

scholarly journals AN ANALYSIS OF THE SELF-ENERGY PROBLEM FOR THE ELECTRON IN QUANTUM ELECTRODYNAMICS

1952 ◽  
Vol 30 (1) ◽  
pp. 70-78
Author(s):  
P. N. Daykin
Keyword(s):  
Quantum Electrodynamics ◽  
The Self ◽  
Positive Energy ◽  
Energy Problem ◽  
Electron Theory ◽  
Hole Theory ◽  
Self Energy ◽  
Virtual Photons ◽  
S Matrix ◽  
The One

Feynman's S-matrix for the self-energy of the free resting electron is evaluated without the restriction that the virtual photons in the intermediate state have only positive energy. Both the one-electron theory and the hole theory of the positron are treated. It is shown that in the one-electron theory the normally quadratically divergent transverse part of the self-energy vanishes if the photon field is assumed to be symmetric in positive and negative energies. A similar theorem does not hold in the hole theory. A particular type of interaction leads to a vanishing self-energy in one-electron theory. However, this does not solve the self-energy problem, as in this case radiation corrections to scattering would vanish as well. The S-matrix for the self-energy of a bound electron is evaluated in a similar manner. The decay probability for an excited state is calculated as the imaginary part of the self-energy. The correct value is obtained only in hole theory and in interaction with positive energy photons. In the special case in which the external field is a uniform magnetic field, again only hole theory with this same interaction gives the correct value for the anomalous magnetic moment.

Quantum Electrodynamics: The Self-Energy Problem

1950 ◽  
Vol 78 (2) ◽  
pp. 98-103 ◽  
Author(s):  
Hartland S. Snyder
Keyword(s):  
Quantum Electrodynamics ◽  
The Self ◽  
Energy Problem ◽  
Self Energy

scholarly journals Remark on the Self Energy Problem of the Photon

1952 ◽  
Vol 7 (5-6) ◽  
pp. 591-592
Author(s):  
O. Hara ◽  
H. Shimazu
Keyword(s):  
The Self ◽  
Energy Problem ◽  
Self Energy

scholarly journals Opacity from Loops in AdS

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Alexandria Costantino ◽  
Sylvain Fichet
Keyword(s):  
Imaginary Part ◽  
Quantum Dynamics ◽  
Model Building ◽  
Asymptotic Properties ◽  
The Self ◽  
Effective Theory ◽  
Self Energy ◽  
Higher Dimensional ◽  
Timelike Region ◽  
Spectral Representations

Abstract We investigate how quantum dynamics affects the propagation of a scalar field in Lorentzian AdS. We work in momentum space, in which the propagator admits two spectral representations (denoted “conformal” and “momentum”) in addition to a closed-form one, and all have a simple split structure. Focusing on scalar bubbles, we compute the imaginary part of the self-energy ImΠ in the three representations, which involves the evaluation of seemingly very different objects. We explicitly prove their equivalence in any dimension, and derive some elementary and asymptotic properties of ImΠ.Using a WKB-like approach in the timelike region, we evaluate the propagator dressed with the imaginary part of the self-energy. We find that the dressing from loops exponentially dampens the propagator when one of the endpoints is in the IR region, rendering this region opaque to propagation. This suppression may have implications for field-theoretical model-building in AdS. We argue that in the effective theory (EFT) paradigm, opacity of the IR region induced by higher dimensional operators censors the region of EFT breakdown. This confirms earlier expectations from the literature. Specializing to AdS5, we determine a universal contribution to opacity from gravity.

scholarly journals Classical gravitational self-energy from double copy

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Gabriel Luz Almeida ◽  
Stefano Foffa ◽  
Riccardo Sturani
Keyword(s):  
Gravitational Field ◽  
Binary System ◽  
The Self ◽  
Gravitational Coupling ◽  
Leading Order ◽  
Body System ◽  
Self Energy ◽  
Composite Systems ◽  
Body Dynamics ◽  
Double Copy

Abstract We apply the classical double copy to the calculation of self-energy of composite systems with multipolar coupling to gravitational field, obtaining next-to-leading order results in the gravitational coupling GN by generalizing color to kinematics replacement rules known in literature. When applied to the multipolar description of the two-body system, the self-energy diagrams studied in this work correspond to tail processes, whose physical interpretation is of radiation being emitted by the non-relativistic source, scattered by the curvature generated by the binary system and then re-absorbed by the same source. These processes contribute to the conservative two-body dynamics and the present work represents a decisive step towards the systematic use of double copy within the multipolar post-Minkowskian expansion.

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