AHARONOV–CASHER EFFECT IN HALF-INTEGER SPIN ANTIFERROMAGNETS

1992 ◽  
Vol 06 (14) ◽  
pp. 871-878 ◽  
Author(s):  
I. V. KRIVE ◽  
A. A. ZVYAGIN
Keyword(s):  
Boundary Conditions ◽  
Ground State ◽  
State Energy ◽  
One Dimensional ◽  
Band Filling ◽  
Mesoscopic Ring ◽  
The One ◽  
Ac Fields ◽  
Analytical Expressions ◽  
Twisted Boundary Conditions

The manifestation of the Aharonov–Casher effect in condensed media is considered. In the one-dimensional Hubbard model with arbitrary band filling we derived analytical expressions for the oscillating part of the ground state energy of mesoscopic ring with twisted boundary conditions which model the influence of Aharonov–Bohn (AB) and/or Aharonov–Casher (AC) fields. It is shown that in the limit of strong on-site repulsion AB-oscillations disappear for half-filled band, but the amplitude of the AC-oscillations, on the contrary, attains its maximum. The period of the AC-oscillations in this case equals hc/2 μ B (μ B is the Bohr magneton).

Quantum mechanics of the damped harmonic oscillator

2002 ◽  
Vol 80 (6) ◽  
pp. 645-660 ◽  
Author(s):  
M Blasone ◽  
P Jizba
Keyword(s):  
Harmonic Oscillator ◽  
Ground State ◽  
Geometric Phase ◽  
State Energy ◽  
Dimensional System ◽  
One Dimensional ◽  
Damped Harmonic Oscillator ◽  
Linear Harmonic Oscillator ◽  
Two Dimensional System ◽  
The One

We quantize the system of a damped harmonic oscillator coupled to its time-reversed image, known as Bateman's dual system. By using the Feynman–Hibbs method, the time-dependent quantum states of such a system are constructed entirely in the framework of the classical theory. The geometric phase is calculated and found to be proportional to the ground-state energy of the one-dimensional linear harmonic oscillator to which the two-dimensional system reduces under appropriate constraint. PACS Nos.: 03.65Ta, 03.65Vf, 03.65Ca, 03.65Fd

scholarly journals PERSISTENT SPIN CURRENT AND ENTANGLEMENT IN THE ANISOTROPIC SPIN RING

2007 ◽  
Vol 21 (06) ◽  
pp. 327-337 ◽  
Author(s):  
ZI-XIANG HU ◽  
YOU-QUAN LI
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Flux ◽  
Ground State ◽  
State Energy ◽  
Spin Current ◽  
Persistent Current ◽  
One Dimensional ◽  
The Magnetic Field ◽  
Twisted Boundary Conditions

We investigate the ground state persistent spin current and the pair entanglement in one-dimensional antiferromagnetic anisotropic Heisenberg ring with twisted boundary conditions. By solving Bethe ansatz equations numerically, we calculate the dependence of the ground state energy on the total magnetic flux through the ring, and the resulting persistent current. Motivated by the recent development of the quantum entanglement theory, we study the properties of the ground state concurrence under the influence of the flux through the anisotropic Heisenberg ring. We also include an external magnetic field and discuss the properties of the persistent current and the concurrence in the presence of the magnetic field.

scholarly journals GROUND-STATE ENERGY OF THE ONE-DIMENSIONAL HUBBARD MODEL IN A SIMPLE SELF-CONSISTENT VERSION OF THE LADDER APPROXIMATION

1995 ◽  
Vol 09 (18) ◽  
pp. 1149-1157 ◽  
Author(s):  
F.D. BUZATU
Keyword(s):  
Hubbard Model ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Consistency Condition ◽  
Ladder Approximation ◽  
Model Parameters ◽  
Simple Assumption ◽  
One Dimensional ◽  
The One

The ground-state energy of the one-dimensional Hubbard model is calculated within the ladder approximation; from the comparison with the exact results in the repulsive case, it follows that the approximation is good at low densities or small couplings. The ladder approximation can be improved by imposing a self-consistency condition; using a simple assumption, the results become close to the exact ones in a large range of the model parameters.

GENERALIZED GUTZWILLER ANSATZ FOR THE HALF-FILLED HUBBARD CHAIN

1988 ◽  
Vol 02 (05) ◽  
pp. 1021-1034 ◽  
Author(s):  
Patrik Fazekas ◽  
Karlo Penc
Keyword(s):  
Wave Function ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Occupation Number ◽  
Step Function ◽  
Spin Correlations ◽  
One Dimensional ◽  
Leading Term ◽  
The One

The well-known Gutzwiller wave function is generalized by including new variational parameters to control nearest-neighbour charge-charge, charge-spin, and spin-spin correlations. The non-magnetic state of the one-dimensional, half-filled Hubbard model is studied. Within the Gutzwiller approximation, the expression for the ground state energy can be worked out analytically. The correlation between empty and doubly occupied sites is found to play the most essential role. Minimization in the large-U limit shows that the Brinkman-Rice transition has been pushed to U → ∞, and the leading term of the ground state energy density is of order −t2/ U . In contrast to results obtained with the Gutzwiller wave function, we find that the band occupation number nk is monotonically decreasing both above and below kF. The dominant k–dependence is given by ~(t/U) cos k, in agreement with t/U–expansion results. nk has also a weak step-function component, with the discontinuity at kF vanishing as (t/U)2 in the limit U/t ≫ 1.

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