Infinite-range quantum random Heisenberg magnet

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We study with exact diagonalization techniques the Heisenberg model for a system of SU(2) spins with S=1/2 and random infinite-range exchange interactions. We calculate the critical temperature Tg for the spin-glass to paramagnetic transition. We obtain Tg≈0.13, in good agreement with previous quant...

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Autores principales: Arrachea, L., Rozenberg, M.J.
Formato: JOUR
Materias:
glass
acceleration
article
calculation
magnet
mathematical analysis
model
Monte Carlo method
quantum mechanics
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01631829_v65_n22_p2244301_Arrachea
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_01631829_v65_n22_p2244301_Arrachea
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spelling todo:paper_01631829_v65_n22_p2244301_Arrachea2023-10-03T15:01:53Z Infinite-range quantum random Heisenberg magnet Arrachea, L. Rozenberg, M.J. glass acceleration article calculation magnet mathematical analysis model Monte Carlo method quantum mechanics We study with exact diagonalization techniques the Heisenberg model for a system of SU(2) spins with S=1/2 and random infinite-range exchange interactions. We calculate the critical temperature Tg for the spin-glass to paramagnetic transition. We obtain Tg≈0.13, in good agreement with previous quantum Monte Carlo and analytical estimates. We provide a detailed picture for the different kind of excitations which intervene in the dynamical response Χ″(ω,T) at T=0 and analyze their evolution as T increases. We also calculate the specific heat Cv(T). We find that it displays a smooth maximum at TM≈0.25, in good qualitative agreement with experiments. We argue that the fact that TM>Tg is due to a quantum disorder effect. Fil:Rozenberg, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01631829_v65_n22_p2244301_Arrachea
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic glass
acceleration
article
calculation
magnet
mathematical analysis
model
Monte Carlo method
quantum mechanics
spellingShingle glass
acceleration
article
calculation
magnet
mathematical analysis
model
Monte Carlo method
quantum mechanics
Arrachea, L.
Rozenberg, M.J.
Infinite-range quantum random Heisenberg magnet
topic_facet glass
acceleration
article
calculation
magnet
mathematical analysis
model
Monte Carlo method
quantum mechanics
description We study with exact diagonalization techniques the Heisenberg model for a system of SU(2) spins with S=1/2 and random infinite-range exchange interactions. We calculate the critical temperature Tg for the spin-glass to paramagnetic transition. We obtain Tg≈0.13, in good agreement with previous quantum Monte Carlo and analytical estimates. We provide a detailed picture for the different kind of excitations which intervene in the dynamical response Χ″(ω,T) at T=0 and analyze their evolution as T increases. We also calculate the specific heat Cv(T). We find that it displays a smooth maximum at TM≈0.25, in good qualitative agreement with experiments. We argue that the fact that TM>Tg is due to a quantum disorder effect.
format JOUR
author Arrachea, L.
Rozenberg, M.J.
author_facet Arrachea, L.
Rozenberg, M.J.
author_sort Arrachea, L.
title Infinite-range quantum random Heisenberg magnet
title_short Infinite-range quantum random Heisenberg magnet
title_full Infinite-range quantum random Heisenberg magnet
title_fullStr Infinite-range quantum random Heisenberg magnet
title_full_unstemmed Infinite-range quantum random Heisenberg magnet
title_sort infinite-range quantum random heisenberg magnet
url http://hdl.handle.net/20.500.12110/paper_01631829_v65_n22_p2244301_Arrachea
work_keys_str_mv AT arracheal infiniterangequantumrandomheisenbergmagnet
AT rozenbergmj infiniterangequantumrandomheisenbergmagnet
_version_ 1807319372701630464

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