# Condensed Matter Seminar Series

## The Dynamics of a (Dissipative) Bose-Hubbard Dimer

### Ted Pudlik

#### Boston University (and visiting at Duke)

##### Thursday March 27, 11:30 am, Room 298, Physics Building

Abstract: Some
of the simplest systems accessible to experiments with ultracold gases
in optical lattices are dimers: atoms in a double-well optical lattice,
or atoms in a single optical trap, but with two interacting spin
states. These systems are very accurately represented by the
Bose-Hubbard dimer. A quantum model with many degrees of freedom, the
Bose-Hubbard dimer can be approximated by classical equations of motion
for just two variables, z, the imbalance in the two wells' atomic
populations, and phi, the wells' relative phase. We study how much of
the quantum system's behavior is captured by this simple classical
picture. Surprisingly, the classical model not only predicts the
dynamics of z and phi, but also contains information about the
entanglement of the modes. It can therefore be used to shed light on
the counterintuitive technique of enhancing entanglement though
controlled dissipation. Further features of the quantum model can be
recovered through semiclassical quantization of the equations of
motion. This approach allows us to obtain closed-form, nonperturbative
estimates of the tunneling rate between the modes.

*Host: Harold Baranger and Josh Socolar*