WRITING ELECTRONIC FERROMAGNETIC STATES IN A HIGH-TEMPERATURE PARAMAGNETIC NUCLEAR SPIN SYSTEM


Autoria(s): SOARES-PINTO, D. O.; TELES, J.; SOUZA, A. M.; AZEVÊDO, Eduardo Ribeiro de; SARTHOUR, R. S.; BONAGAMBA, Tito José; REIS, M. S.; OLIVEIRA, I. S.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2011

Resumo

In this paper, we use Nuclear Magnetic Resonance (NMR) to write electronic states of a ferromagnetic system into high-temperature paramagnetic nuclear spins. Through the control of phase and duration of radio frequency pulses, we set the NMR density matrix populations, and apply the technique of quantum state tomography to experimentally obtain the matrix elements of the system, from which we calculate the temperature dependence of magnetization for different magnetic fields. The effects of the variation of temperature and magnetic field over the populations can be mapped in the angles of spin rotations, carried out by the RF pulses. The experimental results are compared to the Brillouin functions of ferromagnetic ordered systems in the mean field approximation for two cases: the mean field is given by (i) B = B(0) + lambda M and (ii) B = B(0) + lambda M + lambda`M(3), where B(0) is the external magnetic field, and lambda, lambda` are mean field parameters. The first case exhibits second order transition, whereas the second case has first order transition with temperature hysteresis. The NMR simulations are in good agreement with the magnetic predictions.

CNPq

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

CAPES

FAPESP

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Identificador

INTERNATIONAL JOURNAL OF QUANTUM INFORMATION, v.9, n.4, p.1047-1056, 2011

0219-7499

http://producao.usp.br/handle/BDPI/29937

10.1142/S021974991100785X

http://dx.doi.org/10.1142/S021974991100785X

Idioma(s)

eng

Publicador

WORLD SCIENTIFIC PUBL CO PTE LTD

Relação

International Journal of Quantum Information

Direitos

restrictedAccess

Copyright WORLD SCIENTIFIC PUBL CO PTE LTD

Palavras-Chave #Density matrix #electronic ferromagnetic states #nuclear paramagnetic states #MAGNETIC-RESONANCE #QUANTUM COMPUTATION #LOGICAL OPERATIONS #QUADRUPOLAR NUCLEI #TOMOGRAPHY #COMPUTER #PULSES #Computer Science, Theory & Methods #Physics, Particles & Fields #Physics, Mathematical
Tipo

article

original article

publishedVersion