Physics and Astronomy Calendar

Week of Monday, November 19th 2018

Monday, November 19th 2018
12:15 pm:
Speaker: Soumyajit Mandal, Case Western Reserve University
Subject: Ultra-steep-spectrum Sources in Galaxy Clusters
Faculty Host: Thomas W. Jones

Tuesday, November 20th 2018
11:15 am:
Nuclear Physics Seminar in Physics 301-20 Tate
Speaker: Mauricio Martinez Guerrero, North Caroline State University
Subject: Hydrodynamic Fluctuations and Lower Bounds of the Transport Coefficients

In this talk I will discuss the effects of hydrodynamic
fluctuations in non-relativistic and relativistic setups. Within the
framework of stochastic hydrodynamics I obtain a number of model
independent results, including the long-time tail of different
transport coefficients, and the leading non-analyticity of the
correlators of energy, momentum and particle density in
non-relativistic and relativistic setups. The presence of hydrodynamic
fluctuations induce lower bounds on the transport coefficients by
analyzing the low frequency limit of different correlation functions.
I determine the lower bounds of the bulk viscosity over entropy ratio
in a cold Fermi gas near unitarity. When extending this analysis to
the case of a U(1) conformal relativistic expanding fluid we observe
that the values of the shear viscosity and heat conductivity are
bounded from below. In both setups, non-relativistic and relativistic
one, the lower bounds on the transport coefficients are weakly
dependent on assumptions regarding the range of applicability of fluid

1:25 pm:
Space Physics Seminar in Tate 301-20
Speaker: Aaron Breneman, University of Minnesota
Subject: To be announced.
3:00 pm:
Speaker: Xiaoyu Wang, University of Chicago
Subject: Electrical transport near an Ising-nematic quantum critical point

An electronic nematic order spontaneously breaks the rotation symmetry of the many body system, making various physical properties anisotropic. It has been observed in various systems, in particular the cuprate and iron-based high temperature superconductors. In the vicinity of a nematic quantum critical point — achieved by tuning some external parameter such as pressure or doping — the physics is described by that of low-frequency long-wavelength order parameter fluctuations coupled to a Fermi surface. However, due to the momentum-conserving nature of the induced electron-electron interaction, the temperature dependence of the resistivity near an Ising nematic QCP remains unclear. In this talk, we shed light on the problem by incorporating disorder and Umklapp process into the low-energy theory. Our work can be viewed as solving an extended Boltzmann equation, with a collision integral that accounts for complicated multi-particle scattering processes important near the QCP

Faculty Host: Rafael Fernandes

Thursday, November 22nd 2018
No journal club, Thanksgiving Holiday

Friday, November 23rd 2018
4:40 pm:
Thanksgiving - there will not be a speaker this week.

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