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E 4

Research

B123 Birge - (510) 642-7269

Atomic physics involves using near-ideal quantum mechanical objects, atoms, to test the theories and ideas of quantum mechanics and it's implications for many-body and even condensed matter systems. In our experiments, we use a large number (10^4 to 10^5) of cold atoms (<100 nK), currently Rubidium, and possibly Lithium in the future. In this regime, our atoms act as composite particles with a (quantum mechanical) position, momentum, and spin, and with weak repulsive inter-atomic interactions and tunable, controllable interactions with light.

Most experiments in our community try to answer one of two questions: given an interesting Hamiltonian, what will a many-body quantum mechanical system do? and given a system's state, what can we learn about the Hamiltonian? The first question is typically asked in reference to condensed matter physics. How do spinors or mixtures evolve? What is the ground state? Will a particular Hamiltonian produce an unusual superconductor? The latter question is typically asked of precision experiments and interferometry. Given the final spin state of the atoms, what was the environment, the local magnetic field, or the frequency? Given a final momentum or position state, what accelerations did the atoms experience?

Ring Traps

Our current effort is an all-optical ring trap for a Bose-Einstein condensate of Rubidium.

Evaporative cooling of a BEC

We have formed a BEC in an all-optical toroidal potential. With this system we plan to induce a persistent flow of atoms around the ring, known as a vortex (or multiple vortices). One long-term goal of this project is to create a trapped-atom Sagnac interferometer.

Atoms in a ring potential

Rubidium and Lithium

We have the capability to add lithium to our system. We have produced a two-element slow beam and MOT of Rubidium-87 and Lithium-7, and observed light-induced collisions. Our recent efforts have so far been concentrated on creating and studying quantum degenerate Rubidium, but we hope that sympathetic cooling will allow us to produce large, robust mixtures of quantum degenerate Lithium. We don't know exactly what we would study, but one option is to watch a spinor condensate of Lithium and Rubidium evolve, either in a harmonic or a ring optical trap. This system is not well studied, so there is lots of room for discovery.

Microfabrication

Our first approach to ring trap physics involved microfabricating a set of smooth, millimeter-scale coils to create a magnetic toroidal potential. We have produced one complete set of coils and may one day install it. If the coils work as anticipated, we will be able to create uniform micron to millimeter-scale waveguides for ultracold (and even maybe degenerate) Lithium and Rubidium.

What we do

Optics

Electronics

Fun with assembly and design of a wide range of electronic components, from complex analog controllers to microcontroller systems.

Computers

Programming and data analysis, i.e. Matlab galore.

Vacuum

The only good vacuum is ultra-high vacuum.

Calculations

Sometimes we even have to do physics to figure out what we should be doing and what is going on. No theory for that? Make one up!

Making things work

That's right, after you work here you will become a pro at making stuff work. Anything. Know nothing about fixing vacuum leaks? Noisy electronics? Drifting laser beams? Leaky pipes? You will by the time you leave.

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We are looking for a post-doc. Contact Dan!

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