Surface effects in quantum spin chains
| Autor: | J. B. Parkinson |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Physics
Spins Condensed matter physics Heisenberg model Partition function (mathematics) Condensed Matter Physics symbols.namesake symbols Periodic boundary conditions Padé approximant General Materials Science Hamiltonian (quantum mechanics) Series expansion Eigenvalues and eigenvectors Mathematical physics |
| Zdroj: | Journal of Physics: Condensed Matter. 16:S5233-S5241 |
| ISSN: | 1361-648X 0953-8984 |
| DOI: | 10.1088/0953-8984/16/44/020 |
| Popis: | Chains of quantum spins with open ends and isotropic Heisenberg exchange are studied. By diagonalizing the Hamiltonian for chains of finite length N and obtaining all the energy eigenvalues, the magnetic susceptibility X, the specific heat C v , and the partition function Z can be calculated exactly for these chains. The high-temperature series expansions of these are then evaluated. For X and C v it is found that the terms in the series consist of three parts. One is the normal high-T series already known in great detail for the N → ∞ ring (chain with periodic boundary conditions). The other two consist of a 'surface' term and a correction term of order (/T) N . The surface term is found as a series up to and including (1/T) 8 for spin S = 1/2 and 1. Simple Pade approximant formulae are given to extend the range of validity below T = 1. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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