The extension of the random phase approximation in the many-body theory

Within the framework of the many-body theory by using the Random Phase Approximation with Exchange (RPAE) method we calculated the frequency dependent polarizability, refractive index, and Verdet coefficient of some atoms. Calculated time-dependent peculiarities of a set of atoms are very significant in the nano-region and might be important for designing new materials.

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Dynamic response of some atoms: Many-body calculations

Facta universitatis - series Physics Chemistry and Technology ◽

10.2298/fupct0502129t ◽

2005 ◽

Vol 3 (2) ◽

pp. 129-140 ◽

Cited By ~ 1

Author(s):

Aleksandar Tancic ◽

M. Nikolic

Keyword(s):

Random Phase Approximation ◽

Random Phase ◽

Atomic Interaction ◽

Correlation Effects ◽

Many Body ◽

Hartree Fock ◽

Many Body Theory ◽

Correlation Potential ◽

Body Theory ◽

True Correlation

The frequency-dependent polarizability in the Hartree-Fock (HF) approximation has been corrected for true correlation effects by means of many-body theory. The polarizability has been computed in the Random Phase Approximation with Exchange (RPAE) for He, Ar Xe, Kr, Li, Ca through the second (and some higher) order in the correlation potential. With this polarizability as input we obtained the values of some atomic interaction constants.

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Dielectric response of metallic crystal made up of highly polarisable molecules: the semi-classical approach

Open Physics ◽

10.2478/s11534-008-0160-8 ◽

2009 ◽

Vol 7 (4) ◽

Author(s):

Željana Bonačić Lošić ◽

Paško Županović

Keyword(s):

Dielectric Function ◽

Dielectric Response ◽

Random Phase Approximation ◽

Random Phase ◽

Collective Modes ◽

Classical Approach ◽

Phase Approximation ◽

Many Body ◽

Band Insulator ◽

The Many

AbstractThe dielectric response is considered within models of a one-band metal, a two-band insulator and a two-band metal using the semi-classical approximation. Corresponding dielectric functions are found. The dielectric function of two-band metal is found to be the interpolation between the Sellmeyer and Lorenz-Lorentz expressions, respectively. The frequencies of the collective modes are identified as the zeroes of the dielectric functions. The correspondence between the semi-classical approach used in this paper and the many-body calculation within the random-phase approximation is established.

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Hartree–Fock and random phase approximation theories in a many-fermion solvable model

Modern Physics Letters A ◽

10.1142/s0217732315501965 ◽

2015 ◽

Vol 30 (36) ◽

pp. 1550196 ◽

Cited By ~ 2

Author(s):

Giampaolo Co’ ◽

Stefano De Leo

Keyword(s):

Random Phase Approximation ◽

Random Phase ◽

Solvable Model ◽

Phase Approximation ◽

Many Body ◽

Hartree Fock ◽

Ideal System ◽

The Many ◽

Effective Theories ◽

Number Of Particles

We present an ideal system of interacting fermions where the solutions of the many-body Schrödinger equation can be obtained without making approximations. These exact solutions are used to test the validity of two many-body effective approaches, the Hartree–Fock and the random phase approximation theories. The description of the ground state done by the effective theories improves with increasing number of particles.

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