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El programa de Posgrado en Fisica invita a todos para la:

 Sustentación de Tesis

 Luis Cesar Nunes dos Santos

 Alguns Resultados no Estudo de Férmions e Bósons em Espaços Curvos: Soluções das Equações de Dirac e klein-Gordon

Jurados:

 Prof. Dr. Celso de Camargo Barros Junior – (presidente) – FSC/UFSC

Prof. Dr. Sérgio José Barbosa Duarte – (miembro externo) – CBPF

Prof. Dr. Luis Rafael Benito Castro – (miembro externo) – UFMA

Prof. Dr. Sidney dos Santos Avancini – (membro titular) – UFSC/FSC

Prof. Dr. Eduardo Inacio Duzzioni – (miembro titular) – UFSC/FSC

Prof. Dr. Paulo Juliano Liebgott – (miembro titular) – UFSC/FSC

 Fecha: 11 de marzo de 2015 – miércoles – Horario: 9:00 am – Lugar: Sala 212 – Auditorio del Departamento de Física

EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:

Quantum dipolar gases for quantum magnetism  

Laurent Vernac

Laboratoire de Physique des Lasers / Université Paris 13

 Resumen:

 Bose Einstein Condensates (BEC) have been obtained with ultra cold atoms in 1995. In these quantum gases all atoms are in the same quantum state, which gives them unique properties in terms of coherence, and allows for observation of matter interference, superfluidity, or transition from superfluid to Mott insulator states in an optical lattice. I will present experimental results obtained in our group with chromium atoms. Due to the high spin (S=3) in the ground state of chromium, there are large magnetic dipole-dipole interactions (DDIs) between the atoms, which are long range, and anisotropic. They confer specific properties to chromium BECs. For example, the excitation spectrum depends on the direction of the magnetic field: a Cr BEC can be seen as an anisotropic superfluid [1]. DDIs allow as well the change of the magnetization of the sample, which leads to spontaneous depolarization of the BEC at low magnetic fields, and multi-components BECs [2,3]. The main part of my talk will be devoted to the results we have obtained in a 3D optical lattice. We have studied spin exchange dynamics due to DDIs in the Mott insulator state, with one or two atoms per lattice site [4]. Our system is well described by an effective XXZ spin Hamiltonian, with Ising and exchange terms. We thus obtain an interesting system for quantum simulation, which realizes a spin model used in condensed matter physics, with true spin-spin interactions. As correlations build up between the few thousands of atoms loaded in the lattice, our system should reveal as well the existence of entanglement between many particles, through the finding of a relevant experimental entanglement witness. I will conclude by perspectives offered by our recent production of a chromium quantum gas with the fermionic isotope (Fermi Sea) [5].

REFS.:     

[1] Anisotropic Excitation Spectrum of a Dipolar Quantum Bose Gas G. Bismut et al., Phys. Rev. Lett. 109, 155302 (2012)

[2] Spontaneous demagnetization of a dipolar spinor Bose gas atultra-low magnetic field

B. Pasquiou, Phys. Rev. Lett. 106, 255303 (2011)

[3] Thermodynamics of a Bose-Einstein condensate with free magnetization B. Pasquiou et al., Phys. Rev. Lett., 108, 045307 (2012)

[4] Nonequilibrium Quantum Magnetism in a Dipolar Lattice Gas A. de Paz et al., Phys. Rev. Lett., 111, 185305 (2013)

[5] Chromium Dipolar Fermi SeaB. Naylor et al., Phys. Rev. A 91, 011603(R) (2015)

Fecha: 6 de marzo de 2015 – (viernes) – Lugar: Sala 212 Auditorio del Departamento de Física – Horário: 10h15min

El programa de Posgrado en Física invita a todos para la:

 Sustentación de Disertación

  Ivan Eugênio Cunha

 Matéria Nuclear no Universo Primordial

Jurados

 Prof. Dr. Celso de Camargo Barros Junior – (presidente) – FSC/UFSC

Prof. Dr. Manuel Maximo Bastos Malheiro de Oliveira – (miembro externo) – ITA

Prof. Dr. José Ricardo Marinelli – (miembro titular) – UFSC/FSC

Prof. Dr. Sidney dos Santos Avancini – (miembro titular) – UFSC/FSC

Nome do Professor – (miembro suplente) – USP

Fecha: 6 de marzo de 2015 – martes– Horario: 2:00 pm – Lugar: Sala 212 – Auditorio del Departamento de Física

 El programa de Posgrado en Física invita a todos para la:

 Sustentación de Disertación

William Rafael Tavares

 Excitações Mesônicas sob Influência de Campos Magnéticos Fortes

Jurados

 Prof. Dr. Sidney dos Santos Avancini – (presidente) – FSC/UFSC

Prof. Dr. Ricardo Luciano Sonego Farias – (miembro externo) – UFSM

Prof. Dr. Celso de Camargo Barros Junior – (miembro titular) – UFSC/FSC

Prof. Dr. Marcus Emmanuel Benghi Pinto – (miembro titular) – UFSC/FSC

Prof. Dr. José Ricardo Marinelli – (miembro titular) – UFSC/FSC

 Fecha: 2 de marzo de 2015 – lunes– Horario: 10:00 am – Lugar: Sala 212 – Auditorio del Departamento de Física

El Programa de Posgrado en Física invita a todos para:

Examen de Cualificación al Doctorado

 Eduardo Muller dos Santos

 Dinâmica da Informação de Wigner-Yanase para o Modelo de Superradiância de Dicke

Jurados

 Prof. Dr. Eduardo Inacio Duzzioni – (presidente) – FSC/UFSC

Prof. Dr. Jonas Maziero – (miembro externo) – UFSM/FSC

Prof. Dr. Marcelo Henrique Romano Tragtenberg – (miembro titular) – UFSC/FSC

Prof. Dr. Kahio Tibério Mazon – (miembro titular) – UFSC/FSC

Prof. Dr. Frederico Firmo de Souza Cruz – (miembro suplente) – UFSC/FSC

Fecha: 27 de febrero de 2015–sexta-feira– Horario: 9:00 am – Lugar: Sala 212 – Auditorio del Departamento de Física

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Continue a leitura » »