Data: 01/11/2024 (Sexta-feira) <<<<Atenção ao dia diferente
Horário: 14:00 h <<<Atenção ao Horario diferente
Local: sala 201 da torre antiga
Caros estudantes e docentes,
Teremos um seminário extra essa semana. Ele ocorrerá com a apresentação da Profa. Thais Victa Trevisan (IFSC-São Carlos). O título e abstract seguem abaixo.
Tarik em nome da comissão organizadora.
Título: Probing quantum matter with multidimensional spectroscopy
Light-matter interaction is a powerful tool to probe the properties of electrons and
phonons in correlated materials. Recently, multidimensional spectroscopy has gained increasing
attention in condensed matter physics. This technique involves perturbing the system with a
sequence of time-spaced coherent light pulses in the terahertz or optical range. The system’s
response is inherently nonlinear, producing a spectrum that is a function of the independent
frequencies conjugated to the time spacing between pulses, hence the name “multidimensional
spectroscopy.” It has been demonstrated that the multidimensional spectrum reveals
information about the nature, intrinsic lifetimes, and interactions of quasiparticle excitations
which are not easily accessible through single-pulse spectroscopy, making it a promising tool to
probe a wide variety of systems. In this talk, I will introduce the theoretical framework of
multidimensional spectroscopy, highlighting its prospects in studying many-body systems. For
instance, I will show how multidimensional Raman spectroscopy can be used to distinguish
between different types of electronic nematic orders, namely nematic liquids and nematic
glasses. In a nematic liquid, a state recently proposed in tetragonal BaNi₂As₂, rotational
symmetry is not broken, but strong nematic fluctuations lead to distinctive features such as the
dynamical splitting of selected phonon modes. In a nematic glass, on the other hand, rotation
symmetry is broken, yet coexisting orthorhombic domains lead to a fourfold-symmetric
response. Although distinguishing between nematic liquids and glasses poses a challenge for
linear Raman spectroscopy, I will show that multidimensional Raman spectroscopy presents
unique signatures of the liquid phase associated with a dynamic nematic order parameter.