Asymptotic estimate of large orders in perturbation theory for the many-fermion ground state energy

1983 ◽  
Vol 146 (2) ◽  
pp. 473
Keyword(s):  
Perturbation Theory ◽  
Ground State Energy ◽  
Ground State ◽  
Asymptotic Estimate ◽  
State Energy ◽  
The Many

REMARKS ON THE GROUND STATE ENERGY OF THE SPIN-BOSON MODEL: AN APPLICATION OF THE WIGNER–WEISSKOPF MODEL

2001 ◽  
Vol 13 (02) ◽  
pp. 221-251 ◽  
Author(s):  
MASAO HIROKAWA
Keyword(s):  
Perturbation Theory ◽  
Spectral Analysis ◽  
Ground State Energy ◽  
Ground State ◽  
Spectral Properties ◽  
State Energy ◽  
Regularity Condition ◽  
Infrared Singularity ◽  
Regular Perturbation ◽  
Boson Model

For the ground state energy of the spin-boson (SB) model, we give a new upper bound in the case with infrared singularity condition (i.e. without infrared cutoff), and a new lower bound in the case of massless bosons with infrared regularity condition. We first investigate spectral properties of the Wigner–Weisskopf (WW) model, and apply them to SB model to achieve our purpose. Then, as an extra result of the spectral analysis for WW model, we show that a non-perturbative ground state appears, and its ground state energy is so low that we cannot conjecture it by using the regular perturbation theory.

GROUND STATE PERTURBATION OF N-ANYON IN A MAGNETIC FIELD

1993 ◽  
Vol 08 (04) ◽  
pp. 341-348 ◽  
Author(s):  
YUN SOO MYUNG ◽  
J.M. CHOI ◽  
M.J. UM ◽  
C. JUE
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Ground State Energy ◽  
Ground State ◽  
Uniform Magnetic Field ◽  
State Energy ◽  
Energy Shift ◽  
Landau Levels ◽  
Fractional Statistics ◽  
First Order

We study N-anyon of the α-statistics in a uniform magnetic field, to investigate certain properties of the ground state of a fractional statistics. Using the improved bosonic end-perturbation theory, we obtain the first order perturbative energy shift of the ground state energy. It is realized that there exists a second order perturbative energy with Landau levels.

EXACT MANY BODY FERMI-BOSE TRANSMUTATION IN 2+1 DIMENSIONS

1992 ◽  
Vol 06 (22) ◽  
pp. 3543-3553
Author(s):  
D.M. GAITONDE ◽  
SUMATHI RAO
Keyword(s):  
Gauge Field ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Mean Field ◽  
Scalar Interaction ◽  
Many Body ◽  
Ground State Wavefunction ◽  
The Many ◽  
Chern Simons

We show that the low energy limit of relativistic fermions interacting with a statistical gauge field also includes a scalar interaction. When the Chern-Simons (CS) parameter µ=e2/2π and the scalar interaction is precisely that which is obtained through relativistic reduction, the many-body Hamiltonian can be solved exactly, directly in the fermion gauge, for the ground state energy which is zero and the ground state wavefunction which is gauge equivalent to one, characteristic of free bosons. Conversely, for N bosons interacting with a CS gauge field with µ=e2/2π, the mean-field ground state energy is πN2/m, which is characteristic of N free fermions.

scholarly journals About calculation of the ground-state energy of the helium atom

2021 ◽  
Vol 2067 (1) ◽  
pp. 012002
Author(s):  
E V Baklanov ◽  
P V Pokasov ◽  
A V Taichenachev
Keyword(s):  
Perturbation Theory ◽  
Numerical Calculation ◽  
Schrödinger Equation ◽  
Helium Atom ◽  
Ground State Energy ◽  
Ground State ◽  
Schrodinger Equation ◽  
State Energy ◽  
Calculation Results ◽  
The Difference

Abstract Two versions of the numerical calculation of the ground state energy of the helium atom are compared. First, the nonrelativistic Schrödinger equation with a fixed nucleus is solved, and then the perturbation theory is used. Another version solves this problem exactly. Comparison shows that the difference between the calculation results is 94 kHz.

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