Finite-size study of the ground-state energy, susceptibility, and spin-wave velocity for the Heisenberg antiferromagnet

1992 ◽  
Vol 45 (21) ◽  
pp. 12292-12296 ◽  
Author(s):  
Karl J. Runge
Keyword(s):  
Spin Wave ◽  
Wave Velocity ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Finite Size ◽  
Heisenberg Antiferromagnet

scholarly journals The energy correction due to a finite size nucleus of the hydrogen atom confined in a penetrable spherical cavity

2018 ◽  
Vol 64 (4) ◽  
pp. 399
Author(s):  
Norberto Aquino ◽  
Alejandro Rojas ◽  
Henry Montgomery Jr.
Keyword(s):  
Hydrogen Atom ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Finite Size ◽  
Point Particle ◽  
Energy Correction ◽  
A Value ◽  
Free Hydrogen ◽  
Uniform Charge Distribution

We computed accurate values for the ground state energy of a hydrogen atom by a finite spherical barrier of height V0 as a function of the confinement radius . We consider the nucleus as a sphere with a uniform charge distribution instead of as a point particle. The contribution to the ground state energy due to the finite nuclear size is computed as a function of the confinement radius,  and the height of the barrier, V0, using time-independent perturbation theory. For an impenetrable cavity with .5 au, we found that this energy correction is fifty times higher than the corresponding value for the free hydrogen atom. For a finite value of V0,we found that the maximum of the energy correction is reached at a value  which very is close to the position at which the electron density is most compact around to the nucleus. This is confirmed though the Shannon entropy in configuration space.

The ground state of two quantum models of magnetism

1978 ◽  
Vol 56 (7) ◽  
pp. 897-901 ◽  
Author(s):  
J. Oitmaa ◽  
D. D. Betts
Keyword(s):  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Transverse Magnetization ◽  
Heisenberg Antiferromagnet ◽  
Pair Correlations ◽  
Quantum Models ◽  
Infinite Lattices

The ground state energy and pair correlations have been computed exactly for the spin [Formula: see text] XY magnet and isotropic Heisenberg antiferromagnet, for a sequence of finite cells on the square and honeycomb lattices. Precise estimates of the ground state energy of the infinite lattices are obtained by extrapolation. It is predicted that the XY magnet has a non-zero transverse magnetization and the Heisenberg antiferromagnet has a non-zero staggered magnetization in the ground state.

scholarly journals QUANTUM EFFECTS AND BROKEN SYMMETRIES IN FRUSTRATED ANTIFERROMAGNETS

2001 ◽  
Vol 15 (12) ◽  
pp. 1799-1842 ◽  
Author(s):  
LUCA CAPRIOTTI
Keyword(s):  
Monte Carlo ◽  
Excitation Spectrum ◽  
Spin Wave ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Finite Size ◽  
Wave Theory ◽  
Low Energy ◽  
Heisenberg Antiferromagnet ◽  
Néel Order

We investigate the interplay between frustration and zero-point quantum fluctuations in the ground state of the triangular and J1–J2 Heisenberg antiferromagnets, using finite-size spin-wave theory, exact diagonalization, and quantum Monte Carlo methods. In the triangular Heisenberg antiferromagnet, by performing a systematic size-scaling analysis, we have obtained strong evidences for a gapless spectrum and a finite value of the thermodynamic order parameter, thus confirming the existence of long-range Néel order. The good agreement between the finite-size spin-wave results and the exact and quantum Monte Carlo data also supports the reliability of the spin-wave expansion to describe both the ground state and the low-energy spin excitations of the triangular Heisenberg antiferromagnet. In the J1–J2 Heisenberg model, our results indicate the opening of a finite gap in the thermodynamic excitation spectrum at J2/J1≃0.4, marking the melting of the antiferromagnetic Néel order and the onset of a non-magnetic ground state. In order to characterize the nature of the latter quantum-disordered phase we have computed the susceptibilities for the most important crystal symmetry breaking operators. In the ordered phase the effectiveness of the spin-wave theory in reproducing the low-energy excitation spectrum suggests that the uniform spin susceptibility of the model is very close to the linear spin-wave prediction.

THE FINITE-SIZE PROPERTIES OF THE SQUARE LATTICE QUANTUM HEISENBERG ANTIFERROMAGNET

2001 ◽  
Vol 15 (02) ◽  
pp. 61-68
Author(s):  
YUN SONG
Keyword(s):  
Spin Wave ◽  
Wave Velocity ◽  
Low Temperatures ◽  
Finite Size ◽  
Wave Theory ◽  
Square Lattice ◽  
Finite Size Effect ◽  
Heisenberg Antiferromagnet ◽  
Lattice Size ◽  
Lattice Quantum

We study the spin-1/2 square lattice Heisenberg antiferromagnets with finite size by the nonlinear spin-wave theory. At low temperatures, the effects of the lattice size (L×L) on the spin-wave velocity and the staggered magnetization are obtained, respectively. We find that the staggered magnetization is very sensitive to the lattice size, while the finite size effect on the spin-wave velocity is weak. Moreover, the temperature dependence of the correlation length is also discussed. The results we have obtained are in agreement with the results of experiments and numerical simulations.

scholarly journals Magnetization process of the S = 1/2 Heisenberg antiferromagnet on the floret pentagonal lattice

2021 ◽  
Vol 5 (12) ◽  
pp. 125008
Author(s):  
Rito Furuchi ◽  
Hiroki Nakano ◽  
Norikazu Todoroki ◽  
Toru Sakai
Keyword(s):  
Magnetic Field ◽  
Saturation Magnetization ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Heisenberg Antiferromagnet ◽  
Magnetization Process ◽  
Diagonalization Method ◽  
The One ◽  
Peculiar Phenomenon

Abstract We study the S = 1/2 Heisenberg antiferromagnet on the floret pentagonal lattice by numerical diagonalization method. This system shows various behaviours that are different from that of the Cairo-pentagonal-lattice antiferromagnet. The ground-state energy without magnetic field and the magnetization process of this system are reported. Magnetization plateaux appear at one-ninth height of the saturation magnetization, at one-third height, and at seven-ninth height. The magnetization plateaux at one-third and seven-ninth heights come from interactions linking the sixfold-coordinated spin sites. A magnetization jump appears from the plateau at one-ninth height to the plateau at one-third height. Another magnetization jump is observed between the heights corresponding to the one-third and seven-ninth plateaux; however the jump is away from the two plateaux, namely, the jump is not accompanied with any magnetization plateaux. The jump is a peculiar phenomenon that has not been reported.

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