Rice University
Department of Physics & Astronomy

Condensed Matter Seminars
2013 – 2014

Where: Brockman Hall 300
When: Mondays at 4:00 p.m.

September 16, 2013

QUANTUM IMPURITY PHYSICS OF ULTRACOLD ATOMS:
Orthogonality catastrophe, Polarons, and the physics of contact interactions


Dr. Aditya Shashi

Rice University/Harvard University

    The rapid technological developments in the field of ultracold atoms has increased the scope and sophistication of experimentally realizable systems and the probes used to study them. Moreover, the degree of control over the underlying systems coupled with precision measurement devices makes possible clean realizations of non-trivial many-body phenomena which can be precisely, quantitatively characterized over a wide range of energy-scales.

One significant line of progress is the cold atom realization of famous quantum impurity problems, which often arise naturally in solid state systems. I will discuss the highly non-trivial phenomenology of impurities in cold, dilute many-body systems, in and out of equilibrium by presenting two case studies: dilute impurities in (1) a degenerate Fermi gas, (2) in a Bose-Einstein condensate (BEC). I will discuss Anderson's Orthogonality catastrophe for fermions, and the polaronic physics of bosons, describing how signatures of these diverse phenomena manifest in the unique experimental probes developed to study cold atoms, e.g. RF spectroscopy, Ramsey-interference. I will demonstrate how one thus sees old results in a new light, while gaining new insights afforded by the surprising richness of these novel systems by highlighting the differences in the systems in and out of equilbrium, and the emergent universality at all energy scales due to the interplay between the many-body physics of low-energy processes, and the few-body physics of high energy processes, both of which are themselves universal.

September 30, 2013

A Weyl Superconducting Phase and Its Adjacent
Competing Ordered States in URu2Si2

Dr. Pallab Goswami

NHMFL & Florida State University
October 28, 2013

Low energy spin excitations in Fe(Te/Se) superconductors

Prof. Guangyong Xu

Brookhaven National Laboratory

    Spin fluctuations are believed to play important roles in mediating electron pairing in the recently discovered Fe-based superconductors. Similar to the case in other high-Tc families including the high-Tc cuprates and heavy-Fermion superconductors, a spin-resonance and spin-gap are commonly observed when the system enters the superconducting phase. Here I will present results suggesting that in addition to these common signatures, a dramatic change in the spin-dispersion is observed in the Fe(Te/Se) superconductor ("11" compound). The low energy spin excitations from the superconducting and non-superconducting phases in this system are distinctively different. Implications of these results and possible future work will also be discussed. 

November 11, 2013

INTERACTING ELECTRONIC TOPOLOGICAL INSULATORS IN 3D:
Classification and Properties


Prof. Senthil Todadri

Massachusetts Institute of Technology
November 25, 2013

Magnetic vortex crystals in frustrated Mott insulator

Dr. Yoshimoto Kamiya
December 2, 2013
UNCONVENTIONAL SUPERCONDUCTIVITY IN HEAVY FERMIONS

Dr. Filip Ronning

Los Alamos National Laboratory
December 9, 2013
Strongly Correlated Electron for Better Thermoelectrics

Prof. Silke Paschen

Vienna University of Technology
December 16, 2013

Many-body localization and related phenomena

Prof. Vadim Oganesyan

The City University of New York

    Recent work on interacting disordered lattices (e.g. spins) has focused on existence of many-body localization, defined by absence of diffusion and concomitant loss of ergodicity and thermodynamics in strongly excited states.  Many-body localization  implies several deviations from conventional wisdom, including breakdown of eigenstate thermalization hypothesis, emergence of integrability, existence of forbidden phases and phase transitions. This talk consists of an overview of ideas, results and potentially relevant experiments.
 
March 24, 2014

TBA

Prof. Sasha Chernyshev

University of California, Irvine
April 7, 2014
TBA

Prof. Sri Raghu

Stanford University
March 9, 2015
TBA

Prof. Nic Shannon

Okinawa Institute of Science and Technology

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