Wave-number dependence of the static screening function of an interacting electron gas. II. Higher-order exchange and correlation effects

1970 ◽  
Vol 48 (2) ◽  
pp. 167-181 ◽  
Author(s):  
D. J. W. Geldart ◽  
Roger Taylor
Keyword(s):  
Density Dependence ◽  
Ground State ◽  
Electron Gas ◽  
Perturbation Expansion ◽  
Interpolation Formula ◽  
Higher Order ◽  
Wave Number ◽  
Correlation Effects ◽  
Many Body ◽  
Static Screening

An interpolation formula is suggested for the wave-number and density dependence of the static screening function for an interacting electron gas in its ground state. The approximate screening function simulates a number of properties of the exact screening function which have been established by analysis of its many-body perturbation expansion. The accuracy of the interpolation formula is discussed and is considered to be adequate for practical calculations in the range of intermediate metallic densities.

Wave-number dependence of the static screening function of an interacting electron gas. I. Lowest-order Hartree–Fock corrections

1970 ◽  
Vol 48 (2) ◽  
pp. 155-165 ◽  
Author(s):  
D. J. W. Geldart ◽  
Roger Taylor
Keyword(s):  
Coulomb Interaction ◽  
Ground State ◽  
Electron Gas ◽  
Perturbation Expansion ◽  
Wave Number ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Static Screening ◽  
Zero Frequency

The lowest-order Hartree–Fock contributions to the zero frequency screening function are examined for an interacting electron gas in its ground state. Computational methods are developed to treat singularities associated with the bare coulomb interaction and vanishing energy denominators of the many-body perturbation expansion. Numerical results are given. The wave-number dependence in the intermediate (k ~ kF) range differs considerably from that of previous estimates.

THE PAIR DISTRIBUTION FUNCTION OF AN INTERACTING ELECTRON GAS

1967 ◽  
Vol 45 (9) ◽  
pp. 3139-3161 ◽  
Author(s):  
D. J. W. Geldart
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Electron Gas ◽  
Pauli Principle ◽  
Distribution Functions ◽  
Upper And Lower Bounds ◽  
Wave Number ◽  
Many Body ◽  
Many Body Perturbation Theory ◽  
Simple Class

The pair distribution function, in the limit of zero separation, of an interacting electron gas at high and metallic densities is investigated by many-body perturbation theory. It is shown that the usual methods for maintaining self-consistency in approximate calculations violate, in general, the nonnegativity of the pair distribution function. In particular, the Pauli principle yields a rigorous sum rule for the parallel spin density fluctuation propagator which is not satisfied. Upper and lower bounds on one-loop and multiloop contributions to the pair distribution functions are given. These bounds are used to discuss correlation corrections. An improved wave-number dependence is given for Hubbard's (1957) approximation to the screening function and numerical results are given for a simple class of exchange corrections.

Higher-order growth rate of instability of obliquely propagating kinetic Alfvén and ion-acoustic solitons in a magnetized non-thermal plasma

2002 ◽  
Vol 68 (4) ◽  
pp. 285-303 ◽  
Author(s):  
ANUP BANDYOPADHYAY ◽  
K. P. DAS
Keyword(s):  
Growth Rate ◽  
Solitary Waves ◽  
Thermal Plasma ◽  
Perturbation Expansion ◽  
Expansion Method ◽  
Higher Order ◽  
Wave Number ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Non Thermal Plasma

The higher-order growth rate of instability for obliquely propagating kinetic Alfvén and ion-acoustic solitons in a magnetized non-thermal plasma have been obtained by the multiple-scale perturbation expansion method developed by Allen and Rowlands (1993). The growth rate of instability is obtained correct to order k2, where k is the wave number of a long-wavelength plane-wave perturbation. The corresponding lowest-order stability analysis has been considered recently by Bandyopadhyay and Das (2000b). It has been found that the kinetic Alfvén solitary waves are stable at the order of k but are unstable at the order of k2. It has also been found that the growth rate of instability at the order of k for ion-acoustic solitary waves is free from the parameters of the non-thermal plasma but at the order of k2 depends on the parameters of the non-thermal plasma.

REGULAR STRUCTURE OF LOW-LYING STATES FOR ATOMIC NUCLEI UNDER RANDOM INTERACTIONS

2008 ◽  
Vol 17 (supp01) ◽  
pp. 304-317
Author(s):  
Y. M. ZHAO
Keyword(s):  
Ground State ◽  
Collective Motion ◽  
Regular Structure ◽  
Positive Parity ◽  
Many Body ◽  
Random Interactions ◽  
Atomic Nuclei ◽  
Many Body Systems

In this paper we review regularities of low-lying states for many-body systems, in particular, atomic nuclei, under random interactions. We shall discuss the famous problem of spin zero ground state dominance, positive parity dominance, collective motion, odd-even staggering, average energies, etc., in the presence of random interactions.

Stacking angle dependent multiple excitonic resonances in bilayer tungsten diselenide

Nanophotonics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 3881-3887
Author(s):  
Ankit Arora ◽  
Pramoda K. Nayak ◽  
Tejendra Dixit ◽  
Kolla Lakshmi Ganapathi ◽  
Ananth Krishnan ◽  
...  
Keyword(s):  
Chemical Vapour ◽  
Optoelectronic Devices ◽  
Interlayer Coupling ◽  
Higher Order ◽  
Doping Effect ◽  
Many Body ◽  
Si Substrate ◽  
Tungsten Diselenide ◽  
Body Dynamics ◽  
Insight Into

AbstractWe report on multiple excitonic resonances in bilayer tungsten diselenide (BL-WSe2) stacked at different angles and demonstrate the use of the stacking angle to control the occurrence of these excitations. BL-WSe2 with different stacking angles were fabricated by stacking chemical vapour deposited monolayers and analysed using photoluminescence measurements in the temperature range 300–100 K. At reduced temperatures, several excitonic features were observed and the occurrences of these exitonic resonances were found to be stacking angle dependent. Our results indicate that by controlling the stacking angle, it is possible to excite or quench higher order excitations to tune the excitonic flux in optoelectronic devices. We attribute the presence/absence of multiple higher order excitons to the strength of interlayer coupling and doping effect from SiO2/Si substrate. Understanding interlayer excitations will help in engineering excitonic devices and give an insight into the physics of many-body dynamics.

scholarly journals 0+Ground State Dominance in Many-Body Systems

2002 ◽  
Vol 146 ◽  
pp. 644-645
Author(s):  
Yu-Min Zhao ◽  
Akito Arima ◽  
Naotaka Yoshinaga
Keyword(s):  
Ground State ◽  
Many Body ◽  
Many Body Systems

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

scholarly journals Extended lubrication theory: improved estimates of flow in channels with variable geometry

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170234 ◽  
Author(s):  
Behrouz Tavakol ◽  
Guillaume Froehlicher ◽  
Douglas P. Holmes ◽  
Howard A. Stone
Keyword(s):  
Stokes Equations ◽  
Perturbation Expansion ◽  
Accurate Estimate ◽  
Higher Order ◽  
Lubrication Theory ◽  
Channel Height ◽  
Fluid Films ◽  
Flow Characterization ◽  
Systematic Perturbation

Lubrication theory is broadly applicable to the flow characterization of thin fluid films and the motion of particles near surfaces. We offer an extension to lubrication theory by starting with Stokes equations and considering higher-order terms in a systematic perturbation expansion to describe the fluid flow in a channel with features of a modest aspect ratio. Experimental results qualitatively confirm the higher-order analytical solutions, while numerical results are in very good agreement with the higher-order analytical results. We show that the extended lubrication theory is a robust tool for an accurate estimate of pressure drop in channels with shape changes on the order of the channel height, accounting for both smooth and sharp changes in geometry.

Sign in / Sign up

Export Citation Format

Share Document