FIRST-ORDER AND 2ND-ORDER TRANSITIONS BETWEEN QUANTUM AND CLASSICAL REGIMES FOR THE ESCAPE RATE OF A SPIN SYSTEM

Citation
Em. Chudnovsky et Da. Garanin, FIRST-ORDER AND 2ND-ORDER TRANSITIONS BETWEEN QUANTUM AND CLASSICAL REGIMES FOR THE ESCAPE RATE OF A SPIN SYSTEM, Physical review letters, 79(22), 1997, pp. 4469-4472
Citations number
31
Language
INGLESE
art.tipo
Article
Journal title
ISSN journal
0031-9007
Volume
79
Issue
22
Year of publication
1997
Pages
4469 - 4472
Database
ISI
SICI code
0031-9007(1997)79:22<4469:FA2TBQ>2.0.ZU;2-V
Abstract
We have found a novel feature of the bistable large-spin model describ ed by the Hamiltonian H = -DS2 -HxSx. The crossover from thermal to qu antum regime for the escape rate can be either first (H-x < SD/2) or s econd (SD/2 < H-x < 2SD) order, that is, sharp or smooth, depending on the strength of the transverse field. This prediction can be tested e xperimentally in molecular magnets like Mn12Ac.