Physics and Astronomy Calendar

Week of Monday, November 27th 2017

Monday, November 27th 2017
12:15 pm:
Speaker: Nader Mirabolfathi, Texas A&M University
Subject: Directional dark matter detector
Faculty Host: Priscilla Cushman

Wednesday, November 29th 2017
Speaker: Marvin Marshak, University of Minnesota
Subject: Neutrino Experiments at the Soudan Underground Laboratory

I will discuss the 38-year history of proton decay and neutrino experiments
at the Soudan Underground Laboratory, with a focus on the early history
of how and why the lab started and how it developed an extensive program
of physics experiments.

7:00 pm:
Speaker: Philip Kim, Harvard University
Subject: Stacking atomic layers: quest for new materials and physics

Modern electronics has been heavily relied on the technology to confine electrons in the interface layers of semiconductors. In recent years, scientists discovered that various atomically thin materials including graphene, a single atomic carbon layer, can be isolated. In these atomically thin materials, quantum physics allows electrons to move only in an effective 2-dimensional (2D) space. By stacking these 2D quantum materials, one can also create atomic-scale heterostructures with a wide variety of electronic and optical properties. I will discuss the creation of new heterostructures based on atomically thin materials and emerging new physics with technological implications therein.

Thursday, November 30th 2017
10:10 am:
Biophysics Seminar in 120 PAN
Speaker: David Odde, University of Minnesota
Subject: To be announced.
Speaker: Vihang Mehta and Tom Jones
3:35 pm:
Speaker: Philip Kim, Harvard University
Subject: Unusual quasiparticle correlation in graphene
Fall 2017 Van Vleck Lecturer

Interactions between particles in quantum many-body systems can lead to a collective behavior. In a condensed matter system consisting of weakly interacting particles, a propagating particle interacting with its surroundings can be viewed as a ‘dressed’ quasiparticle with renormalized mass and other dynamic properties. The lack of screening enables strong Coulomb interactions between charged particles, leading to new collective dynamics. In this talk, I will discuss three examples concerning strongly interacting quasiparticles in graphene. In the first example, it will be shown that the thermally populated electrons and holes to realize Dirac fluid, where a huge violation of Wiedemann-Franz law is observed. The second example is realizing magnetoexcitons to correlated the quasiparticles in quantized Landau levels to form magnetoexcitons, which can condense into Bose-Einstein condensation. Finally, we will also discuss another way of correlated quasi-particles in graphene using superconducting proximity effect. Here, we employ the crossed Andreev reflection across thin type II superconducting electrodes to correlated spatially separated quasiparticles. Under strong magnetic fields, the quantum Hall edge states can carry these quasiparticles.

Friday, December 1st 2017
Speaker: Vitaly Vanchurin (UMN Duluth)
Subject: General Relativity from Non-Equilibrium Thermodynamics of Quantum Information

In this talk I will argue that general relativity may be viewed as a useful limit of quantum mechanics with many degrees of freedom, very much like thermodynamics is a useful limit of classical mechanics with many degrees of freedom. First, I will construct statistical ensembles of ket-vectors using spatially covariant dual field theories with a metric tensor playing the role of a conjugate thermodynamic variable to the so-called information tensor (which is related to both Fisher matrix and Fubini-Study metric). Secondly, I will analyze evolution of the ensembles of ket-vectors to argue that an approximate space-time covariance of the dual field theories can be achieved if certain quantum computational complexities are minimized. And finally, I will show that minimization of a non-equilibrium entropy production can lead to the Einstein-Hilbert dynamics of the metric tensor for a particularly simple and highly symmetric form of the Onsager tensor.

Speaker: Shea Brown, U of Iowa
Refreshments to be served in the MIfA Interaction Area (Tate 285-11) following the colloquium.
Faculty Host: Lawrence Rudnick
Speaker: Nora Berenstain, Department of Philosophy - University of Tennessee-Knoxville
Subject: Active Ignorance and the Rhetoric of Biological Race Realism
Refreshments served at 3:15 p.m.

Biological race realism is frequently assumed in scientific investigations into presumed connections between race and physical and psychological features such as intelligence, temperament, criminality, and athleticism. I analyze ways scientists and philosophers actively cultivate ignorance surrounding biological race science by using rhetorical tools to portray critiques of biological race realism as in opposition to science itself. These rhetorical strategies involve painting substantive scientific criticisms—such as questions about empirical and methodological issues with data interpretation, unjustified background assumptions, and failure to rule out alternative explanations of data—as motivated purely by ideological concerns. These rhetorical strategies invoke an assumed distinction between epistemic and non-epistemic values in science and misrepresent criticisms of biological race realism as existing wholly outside the realm of epistemic values.

4:40 pm:
Speaker: Bob Lysak, University of Minnesota
Subject: To be announced.

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