Ground states and elementary excitations of quantum antiferromagnets

Nandini Trevedi, David M. Ceperley

重喜 森

Subir Sachdev A, Kwon Park

Xu Jing

Using bosonization and quantum self-consistent method,the elementary excitation of Spin-Peierls(SP)system is studied. We calculate and discuss ground state and the one-particle excited state of the SP system. By analyzing the self-consistent equation of K, we obtain that the SP system exhibits two phases, i.e. gapful dimerized phase and gapless antiferromagnetic phase. The variation of the ground state and energy gap with frustration parameter has also been investigated.

S. Redner, P. L. Krapivsky

We investigate the zero-temperature coarsening dynamics of a chain of Ising spins with a nearest-neighbour ferromagnetic and an nth-neighbour antiferromagnetic interactions. For sufficiently large antiferromagnetic interaction, the ground state consists of n consecutive up spins followed by n down spins, etc. We show that the asymptotic coarsening into this ground state can be described in terms of a multispecies reactive gas of elementary excitations. The basic elementary excitations are identified and each decays at a different power-law rate in time. The dominant excitations are domains of n + 1 spins which diffuse freely and disappear through processes which are effectively governed by (n + 1)-particle annihilation. This leads to a slow temporal approach to the ground state.

S. Redner, P. L. Krapivsky

We investigate the zero-temperature coarsening dynamics of a chain of Ising spins with a nearest-neighbour ferromagnetic and an n th-neighbour antiferromagnetic interactions. For sufficiently large antiferromagnetic interaction, the ground state consists of n consecutive up spins followed by n down spins, etc. We show that the asymptotic coarsening into this ground state can be described in terms of a multispecies reactive gas of elementary excitations. The basic elementary excitations are identified and each decays at a different power-law rate in time. The dominant excitations are domains of n + 1 spins which diffuse freely and disappear through processes which are effectively governed by ( n + 1)-particle annihilation. This leads to a slow temporal approach to the ground state.