General representation of physical quantities in scheme-invariant perturbation theory and its optimization

1987 ◽  
Vol 70 (2) ◽  
pp. 158-164
Author(s):  
V. I. Vovk ◽  
S. I. Maksimov
Keyword(s):  
Perturbation Theory ◽  
General Representation ◽  
Physical Quantities ◽  
Invariant Perturbation Theory

scholarly journals Stochastic computation of g − 2 in QED

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ryuichiro Kitano ◽  
Hiromasa Takaura ◽  
Shoji Hashimoto
Keyword(s):  
Perturbation Theory ◽  
Numerical Computation ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Stochastic Perturbation ◽  
Higher Order ◽  
Feynman Diagrams ◽  
Perturbative Series ◽  
Physical Quantities

Abstract We perform a numerical computation of the anomalous magnetic moment (g − 2) of the electron in QED by using the stochastic perturbation theory. Formulating QED on the lattice, we develop a method to calculate the coefficients of the perturbative series of g − 2 without the use of the Feynman diagrams. We demonstrate the feasibility of the method by performing a computation up to the α3 order and compare with the known results. This program provides us with a totally independent check of the results obtained by the Feynman diagrams and will be useful for the estimations of not-yet-calculated higher order values. This work provides an example of the application of the numerical stochastic perturbation theory to physical quantities, for which the external states have to be taken on-shell.

Higher orders in the invariant perturbation theory for chiral lagrangians

1973 ◽  
Vol 8 (2) ◽  
pp. 117-120 ◽  
Author(s):  
L. D. Faddeev ◽  
A. A. Slavnov
Keyword(s):  
Perturbation Theory ◽  
Chiral Lagrangians ◽  
Invariant Perturbation Theory

Atomic Forces

2021 ◽  
pp. 93-130
Author(s):  
C. Julian Chen
Keyword(s):  
Perturbation Theory ◽  
Van Der Waals ◽  
Hard Core ◽  
Covalent Bond ◽  
Van Der Waals Force ◽  
Mathematical Form ◽  
Ionic Bond ◽  
Bond Force ◽  
Flat Sample ◽  
Physical Quantities

This chapter discusses the physics and properties of four types of atomic forces occurring in STM and AFM: the van der Waals force, the hard core repulsion, the ionic bond, and the covalent bond. The general mathematical form of the van der Waals force between a tip and a flat sample is derived. The focus of this chapter is the covalent-bond force, which is a key in the understanding of STM and AFM. The concept of covalent bond is illustrated by the hydrogen molecular ion, the prototypical molecule used by Pauling to illustrate Heisenberg’s concept of resonance. The Herring-Landau perturbation theory of the covalent bond, an analytical incarnation of the concept of resonance, is presented in great detail. It is then applied to molecules built from many-electron atoms, to show that the perturbation theory can be applied to practical systems to produce simple analytic results for measurable physical quantities with decent accuracy.

Thermal Properties of the FCC Al3Zr : First-Principles Study

2010 ◽  
Vol 650 ◽  
pp. 313-319 ◽  
Author(s):  
Dong Lin Li ◽  
Ping Chen ◽  
Jian Xiong Yi ◽  
Bi Yu Tang ◽  
Li Ming Peng ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Functional Theory ◽  
Density Functional Perturbation Theory ◽  
Wide Range ◽  
The Face ◽  
Ab Inito ◽  
Physical Quantities

Ab inito density functional theory (DFT) and density function perturbation theory (DFPT) have been applied to investigate the thermal properties of the face-center-cubic (fcc) Al3Zr alloy over a wide range of pressure and temperature. Phonon dispersions were obtained at equilibrium and strained configurations by density functional perturbation theory. Using the quasiharmonic approximation for the free energy, several interesting physical quantities such as thermal Grüneisen parameter, heat capacity at constant pressure and volume, thermal expansion coefficient and entropy, as well as adiabatic bulk modulus and isothermal bulk modulus, were calculated as a function of temperature and pressure, and the variation features of these quantities were discussed in details.

scholarly journals S-duality invariant perturbation theory improved by holography

2017 ◽  
Vol 2017 (4) ◽  
Author(s):  
Abhishek Chowdhury ◽  
Masazumi Honda ◽  
Somyadip Thakur
Keyword(s):  
Perturbation Theory ◽  
Invariant Perturbation Theory
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