Society of Physics Students

hbar@phys.columbia.edu

Columbia University in the City of New York

Fall 2005

 December 1, 2005

Speaker: Professor Charles Hailey , Columbia University

Talk Title: A New Approach In Dark Matter Detection

Abstract:

I will discuss using exotic atom spectroscopy as a novel approach to the detection of supersymmetric dark matter. When neutralinos (the lightest supersymmetric particle) annihilate with each other, they can, on rare occasions, form antideuterons (a nucleus with one antiproton and one antineutron). These antideuterons can be captured into atoms due to their negative charge. The resulting exotic atom deexcites with the emission of X-rays, and a burst of pions when the antideuteron meets the nucleus. This signature is a very clean indicator of antideuteron capture, and thus dark matter. We are studying using this approach in a balloon based search for dark matter. The same approach has recently been suggested as an unusually effective way to search for Kaluza-Klein dark matter, which produces copious antideuterons in annihilation. Antideuteron detection is also the most effective way to set limits on the existence of primoridial black holes.

 November 17, 2005

Speaker: Professor Lam Hui , Columbia University

Talk Title: Cosmology and Grad School

Abstract:

I will talk mainly about current research in cosmology, and a little about graduate schools.

 October 13, 2005

Speaker: Professor Andrew Millis, Columbia University

Talk Title: (Quantum) Condensed Matter Physics

Abstract:

I will briefly explain why (I think) quantum condensed matter physics is interesting, with examples drawn from recent research.

 September 27, 2005

Speaker: Jennifer Blum, Undergraduate at Columbia University

Talk Title: Stellar Winds in Cool Stars

Abstract:

What is a stellar wind? Where is it strongest and in which stars is it most prevalent? Using spectra of infrared regions in cool stars from the Canada-France-Hawaii Telescope (CFHT) and the Nordic Optical Telescope (NOT), I will analyze the presence and strength of the He I line located at 10830 Angstroms to determine the speed of stellar winds in cool stars of spectral types F, G, K, and M.

 September 22, 2005

Speaker: Arthur Lipstein

Talk Title: Nonabelian Fractional Quantum Hall States and Topological Quantum Computation

Abstract:

The computational power of a quantum computer is potentially far greater than that of any classical device. It is difficult to harness this power however, because quantum information is easily destroyed by entanglement with the outside world. It has recently been suggested that certain fractional quantum Hall states may exhibit particle-like excitations which obey nonabelian statistics and can subsequently be used to store quantum information in topologically protected qubits. In this talk, I will discuss how these topological states arise and how they can be manipulated to carry out computations. I will also describe an experimental proposal for measuring and manipulating a topological qubit in a nonabelian quantum Hall state.