Quantum spin glass : a replica-symmetric theory with positive entropy
Autor(a) principal: | |
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Data de Publicação: | 1986 |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/103630 |
Resumo: | In the present paper we present a detailed analysis of quantum effects in the spin-glass transition as described by a quantum Heisenberg analogue of the Sherrington-Kirkpatrick model. The spin operators are represented in terms of two fermion fields and the problem is reduced to that of n fermion leveis at one site in a random time-dependent field and with an interaction delocalized in time. It is shown that within a Hartree-Fock approximation in a replica-symmetric theory one obtains a mean-field description of the transition with satisfactory zero-temperature properties. The transition is described by two order parameters: the static magnetic susceptibility and the spin-glass order parameter. The saddle-point equations obtained in this work are analogous to those of Sommers for a theory of classical spins. |
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Theumann, Alba Graciela Rivas de2014-09-23T02:12:28Z19860163-1829http://hdl.handle.net/10183/103630000112958In the present paper we present a detailed analysis of quantum effects in the spin-glass transition as described by a quantum Heisenberg analogue of the Sherrington-Kirkpatrick model. The spin operators are represented in terms of two fermion fields and the problem is reduced to that of n fermion leveis at one site in a random time-dependent field and with an interaction delocalized in time. It is shown that within a Hartree-Fock approximation in a replica-symmetric theory one obtains a mean-field description of the transition with satisfactory zero-temperature properties. The transition is described by two order parameters: the static magnetic susceptibility and the spin-glass order parameter. The saddle-point equations obtained in this work are analogous to those of Sommers for a theory of classical spins.application/pdfengPhysical review. B, Condensed matter. New York. Vol. 33, no. 1 (Jan. 1986), p. 559-566Física da matéria condensadaVidros de spinTeoria quânticaFermionsSuscetibilidade magnéticaCálculos de HFQuantum spin glass : a replica-symmetric theory with positive entropyEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL000112958.pdf000112958.pdfTexto completo (inglês)application/pdf898927http://www.lume.ufrgs.br/bitstream/10183/103630/1/000112958.pdf57f85e037526a7abe8c4cbed5f186085MD51TEXT000112958.pdf.txt000112958.pdf.txtExtracted Texttext/plain24880http://www.lume.ufrgs.br/bitstream/10183/103630/2/000112958.pdf.txt38707698dae2c1db18573e239d9fbf4dMD5210183/1036302018-06-07 02:32:39.99077oai:www.lume.ufrgs.br:10183/103630Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2018-06-07T05:32:39Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Quantum spin glass : a replica-symmetric theory with positive entropy |
title |
Quantum spin glass : a replica-symmetric theory with positive entropy |
spellingShingle |
Quantum spin glass : a replica-symmetric theory with positive entropy Theumann, Alba Graciela Rivas de Física da matéria condensada Vidros de spin Teoria quântica Fermions Suscetibilidade magnética Cálculos de HF |
title_short |
Quantum spin glass : a replica-symmetric theory with positive entropy |
title_full |
Quantum spin glass : a replica-symmetric theory with positive entropy |
title_fullStr |
Quantum spin glass : a replica-symmetric theory with positive entropy |
title_full_unstemmed |
Quantum spin glass : a replica-symmetric theory with positive entropy |
title_sort |
Quantum spin glass : a replica-symmetric theory with positive entropy |
author |
Theumann, Alba Graciela Rivas de |
author_facet |
Theumann, Alba Graciela Rivas de |
author_role |
author |
dc.contributor.author.fl_str_mv |
Theumann, Alba Graciela Rivas de |
dc.subject.por.fl_str_mv |
Física da matéria condensada Vidros de spin Teoria quântica Fermions Suscetibilidade magnética Cálculos de HF |
topic |
Física da matéria condensada Vidros de spin Teoria quântica Fermions Suscetibilidade magnética Cálculos de HF |
description |
In the present paper we present a detailed analysis of quantum effects in the spin-glass transition as described by a quantum Heisenberg analogue of the Sherrington-Kirkpatrick model. The spin operators are represented in terms of two fermion fields and the problem is reduced to that of n fermion leveis at one site in a random time-dependent field and with an interaction delocalized in time. It is shown that within a Hartree-Fock approximation in a replica-symmetric theory one obtains a mean-field description of the transition with satisfactory zero-temperature properties. The transition is described by two order parameters: the static magnetic susceptibility and the spin-glass order parameter. The saddle-point equations obtained in this work are analogous to those of Sommers for a theory of classical spins. |
publishDate |
1986 |
dc.date.issued.fl_str_mv |
1986 |
dc.date.accessioned.fl_str_mv |
2014-09-23T02:12:28Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/103630 |
dc.identifier.issn.pt_BR.fl_str_mv |
0163-1829 |
dc.identifier.nrb.pt_BR.fl_str_mv |
000112958 |
identifier_str_mv |
0163-1829 000112958 |
url |
http://hdl.handle.net/10183/103630 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Physical review. B, Condensed matter. New York. Vol. 33, no. 1 (Jan. 1986), p. 559-566 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
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application/pdf |
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reponame:Repositório Institucional da UFRGS instname:Universidade Federal do Rio Grande do Sul (UFRGS) instacron:UFRGS |
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UFRGS |
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Repositório Institucional da UFRGS |
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Repositório Institucional da UFRGS |
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