O Programa de Pós-graduação em Física convida a todos para:

Defesa de Dissertação*

Marcos da Maia Vicente Júnior

BUSCAS POR TRÂNSITOS PLANETÁRIOS AO REDOR DE ESTRELAS ANÃS M DA REGIÃO DO BOJO GALÁCTICO

*(evento de reposição da disciplina seminários)

Banca Examinadora

Prof. Dr. Roberto Kalbusch Saito – (presidente) – UFSC/FSC
Prof. Dr. Rubens Tadeu Delgado Duarte – (membro externo) – UFSC/MIP/CCB
Prof. Dr. Daniel Ruschel Dutra – (membro titular) – UFSC/FSC

Data: 9 de abril de 2019 – terça-feira – Horário: 14 horas – Local: Sala 114 – Sala de Reuniões do Departamento de Física

O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário:

Pattern-formation and Critical Behaviour in Dipolar Bose-Einstein Condensates*

Fabian Maucher
Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark

*Evento de reposição para os alunos matriculados na disciplina seminários

Resumo:

Fabian Maucher, Yong-Chang Zhang, and Thomas Pohl
Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark

The formation of patterns with long-range order continues to fascinate scientists from a broad range of natural sciences [1]. In this talk I will discuss pattern-formation in dipolar Bose-Einstein condensates. In this system the possibility of obtaining quantum states with self-organized long-ranged ordering can be facilitated by quantum fluctuations which suppress collapse and pave the way for supersolids in this system [2]. Here, supersolidity refers to a state of matter which displays long-range ordering whilst maintaining a large superfluid fraction. I will present recent results which focus on the critical behaviour of the superfluid-supersolid phase-transition [3] and the crucial role quantum fluctuations can play for the latter. We find that quantum fluctuations can alter the order of the phase transition from first- to second order. Furthermore, apart from the usual triangular lattice of density droplets, quantum fluctuations can give rise to a novel quantum state whose density distribution displays a honeycomb structure.
∗
[1] A. M. Turing, Philos. Trans. Royal Soc. B 23 237 (1952).
[2] H. Kadau, M. Schmitt, M. Wenzel, C. Wink, T. Maier, I. Ferrier-Barbut, T. Pfau, Nature 530 194 (2016).
[3] Y. Zhang, F.M., T. Pohl, arXiv:1903.06161v1 (2019).

Data: 09 de abril de 2019 – (terça-feira) Local: Sala 212 – Auditório do Departamento de Física – Horário: 16 horas

O PROGRAMA DE PÓS-GRADUAÇÃO EM FÍSICA convida para o seminário:

A física nuclear como ferramenta para explicar magnetares e ondas gravitacionais*

Profª. Drª. Débora Peres Menezes UFSC/FSC

*Evento de reposição para os alunos matriculados na disciplina seminários

Resumo:

A neutron star was first detected as a pulsar in 1967. It is one of the most mysterious objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In 2017, a gravitational wave was detected (GW170817) and its source was identified as the merger of two neutron stars. The same event was seen in X-ray, gamma-ray, UV, IR, radio frequency and even in the optical region of the electromagnetic spectrum, starting the new era of multi-messenger astronomy. To understand neutron stars, an appropriate equation of state that satisfies bulk nuclear matter properties has to be used and GW170817 has provided some extra constraints to determine it.
On the other hand, some neutron stars have strong magnetic fields up to 10 to the 15 Gauss on the surface as compared with the usual 10 to the 12 Gauss normally present in ordinary pulsars. They are called magnetars. While the description of ordinary pulsars is not completely established, describing magnetars poses a real challenge because the magnetic fields can produce an anisotropic equation of state. It is also known that low magnetic fields do not affect the equation of state and the resulting star macroscopic properties but they do affect the crust-core transition and the crust thickness with many consequences, as the explanation of glitches and the calculation of the Love number and quadrupole tidal polarisabilities.I will talk about the importance of the new constraints imposed by GW170817 in the determination of appropriate equations of state, possible ways to describe hadronic and quark matter subject to strong magnetic fields and the problems that lie ahead in the understanding of magnetars.

Data: 05 de abril de 2019 – (sexta-feira) – Local: Sala 212 – Auditório do Departamento de Física – Horário: 10h15min