Quantum over breakfast Quantum over breakfast

Fall 2012


September 7

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Mahmoud Lababidi, GMU
Weyl superconductors: an introduction

September 14

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Khan Mahmoud, JQI
Creating Schrodinger's cat state with Bose-Einstein condensates in multiple wells

Quantum superposition principle, when applied to macroscopic objects, gives rise to seeming paradoxes as highlighted by Schrodinger in his famous thought experiment involving dead-and-alive cats. Unlike superpositions of different spin states of an electron, a classical object such as a cat cannot be found in a superposition of two distinct states. I will present a proposal for creating such highly entangled states with ultracold atomic BEC in a multiple well setting. Motivated by the unstable equilibrium dynamics of a rigid pendulum, I will discuss how a BEC in a double well can be evolved into a superposition of hundreds of particles simultaneously in both wells. I then generalize this method to BEC in multiple wells showing the creation of multi-positional cat states. Possible applications of cat states include precision measurements, quantum information processing, testing quantum-classical boundary, etc.

September 21

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Brandon Anderson, JQI
Synthetic gauge fields in cold atoms

Recent experimental success in controlling cold atoms has opened the door to observing phenomena predicted in condensed matter systems, as well as new novel states of matter. Of particular interest is the ability to induce a vector potential to simulate either magnetic fields or spin-orbit coupling. In this talk I will begin with a brief overview of experimental and theoretical advances in the field of synthetic gauge fields. I will then discuss synthetic 3D spin-orbit coupling of the form p.S, known as Weyl coupling. At a large spin-orbit coupling parameter, the low-energy states undergo a dimensional reduction from three to one dimension, which could alternatively be viewed as an enhancement of the low energy density-of-states. The consequences for such a coupling will be discussed in many-body systems of both bosonic and fermionic cold atoms. It is found that for fermions, the spin-orbit coupling will give rise to a bound state for an arbitrarily weak interaction. Furthermore, this bound state is "one dimensional" in the sense that the energy of the bound state is algebraic in the interaction strength. For a bosonic system, the ground state depends on the interaction strength. In the weakly interacting limit, the ground state is a skyrmion; above a critical interaction strength, the ground state develops a lattice structure. Finally, the viability of measuring these states experimentally will be discussed.

October 12

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Phil Rubin, GMU
TBA

October 26

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Anzi Hu
TBA

November 2

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Victor Vakaryuk, Johns Hopkins University
TBA

November 9

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

Enrico Rossi, William and Mary
TBA

November 16

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

James Murray, Johns Hopkins University
TBA

November 30

QOB informal seminar

Science and Technology I, Room 306, 11am (+ lunch after noon)

So Takei, University of Maryland
TBA