Physics Colloquia

February, 02/06/2016
Events and times subject to change

February 8, 2016 Monday 12:30 PM  +
Meyer 433
Physics Colloquia (colloquia)


Hanghui Chen

Charge-transfer-driven Emergent Phenomena in Oxide Heterostructures

Charge transfer is a common phenomenon at oxide interfaces. We use first-principles calculations to show that via heterostructuring of transition metal oxides, the electronegativity difference between two dissimilar transition metal ions can lead to high level of charge transfer and induce substantial redistribution of electrons and ions. Notable examples include i) designing a new Mott insulator via a charge-transfer-driven metal-insulator transition [1]; ii) tailoring magnetic structures and inducing interfacial ferromagnetism [2]; iii) engineering orbital splitting and inducing a non-cuprate single-orbital Fermi surface [3]. Utilizing charge transfer to induce emergent electronic/magnetic/orbital properties at oxide interfaces is a robust approach. Combining charge transfer with quantum confinement and expitaxial strain provides an appealing prospect of engineering electronic structure of artificial oxide heterostructures.


February 11, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Lisa Randall
Harvard University

Double Disk Dark Matter



February 18, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Randy Kamien

Pure and Applied Smectics

I will discuss the homotopic classification of topological defects in liquid crystals with special attention to systems with broken translational symmetry. In the simplest case of smectics, we can see that this classification breaks down and needs repair or reformulation. I will discuss the latter and show how it leads to a surprising, underlying symmetry in smectic ground states. In related work epitaxially assembled toric focal conic domain (TFCD) arrays of smectic-A liquid crystals onto pillar arrays. The 3D nature of the pillar array is crucial to confine and direct the formation of TFCDs on the top of each pillar and between neighboring pillars, leading to highly ordered square and hexagonal array TFCDs persisting deeply into the bulk. Finally, exploiting our two experiences with these materials, we study the flower-like pattern shown on the left and develop new rules for tying together equally-spaced layers in thin films.


February 25, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Steve Kivelson

High Temperature Superconductivity in the Cuprates

The discovery of high temperature superconductivity in the cuprates in 1986 triggered a spectacular outpouring of creative and innovative scientific inquiry. Much has been learned over the ensuing 28 years about the novel forms of quantum matter that are exhibited in this strongly correlated electron system. This progress has been made possible by improvements in sample quality, coupled with the development and refinement of advanced experimental techniques. In part, avenues of inquiry have been motivated by theoretical developments, and in part new theoretical frameworks have been conceived to account for unanticipated experimental observations. An overall qualitative understanding of the nature of the superconducting state itself has been achieved, while profound unresolved issues have come into increasingly sharp focus concerning the astonishing complexity of the phase diagram, the unprecedented prominence of various forms of collective fluctuations, and the simplicity and insensitivity to material details of the “normal” state at elevated temperatures. New conceptual approaches, drawing from string theory, quantum information theory, and various numerically implemented approximate approaches to problems of strong correlations are being explored as ways to come to grips with this rich tableaux of interrelated phenomena.


March 3, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Joe Checkelsky

TBA



March 10, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


John Condeelis
Albert Einstein College of Medicine

TBA



March 24, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Andrea Liu

TBA



March 31, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Michael Rubinstein

TBA



April 7, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Claire Max

TBA



April 14, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Stephen Shenker

TBA



April 21, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Ann Nelson
University of Washington

TBA



April 28, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Josh Frieman

TBA



May 5, 2016 Thursday 4:00 PM  +
Meyer 122
Physics Colloquia (colloquia)


Savas Dimopoulos

TBA