## Physics & Astronomy ETDs

7-2-2012

#### Abstract

A dilute gas Bose Einstein condensate (BEC) is a state of matter that occurs when a cloud of atoms in a potential are made cold and dense enough that they all occupy the potential's ground state. The onset of this phenomenon occurs when their de Broglie wavelength, $\Lambda = \sqrt{2 \pi \hbar^2/mk_BT}$, becomes comparable in size to the inter-particle spacing. A BEC is a macroscopic quantum object, since all atoms in the BEC are described by a single quantum wavefunction and, as such, is a fundamental quantum many-body system. The first experimental demonstration of a dilute gas BEC was performed by Eric Cornell and Carl Wieman in 1995 and since then, several dozen groups around the world have achieved and study BECs. This thesis documents design and construction work performed in support of the Bose Einstein Condensate (BEC) experiment at the Los Alamos National Laboratory. The objective of the work performed was to upgrade the existing BEC machine in most of its significant subsystems to attain better experimental cycle times and BECs with a larger atom number than what was previously attainable, as well as improve the optical quality of the imaging and laser manipulation beams at the location of the BEC. These objectives were achieved through the construction of a new laser system with greater power and larger magneto-optical trap (MOT) beam diameters, a new quadrupole magnetic trap with better optical access and higher magnetic field gradients than the Ioffe-Pritchard coil configuration it replaced, and a cuvette-style quartz cell with a much higher optical quality than the hand-blown cell used previously. In addition to these improvements the feasibility of using phase-contrast imaging of the BECs created in this machine for future experimental goals was evaluated and found to be feasible.

Physics

Masters

#### Department Name

Physics & Astronomy

Deutsch, Ivan

#### First Committee Member (Chair)

Wolfgang, Rudolph

#### Second Committee Member

Boshier, Malcolm

Department of Energy/Los Alamos National Laboratory

English

#### Keywords

Bose-Einstein condensation, Gas condensers, Phase-contrast microscopy.

Thesis

COinS