Matthew B. Squires

A compact, transportable, microchip-based system for high repetition rate production of Bose–Einstein condensates

We present a compact, transportable system that produces Bose–Einstein condensates near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m3, operates at a repetition rate as high as 0.3 Hz, and consumes an average power of 525 W. Evaporative cooling in a chip trap with trap frequencies of several kilohertz leads to nearly pure condensates containing 1.9×104 R87b atoms. Partial condensates are observed at a temperature of 1.58(8) μK, close to the theoretical transition temperature of 1.1 μK.We propose a compact atomic clock based on ultracold Rb atoms that are magnetically trapped near the surface of an atom microchip. An interrogation scheme that combines electromagnetically-induced transparency (EIT) with Ramseys method of separated oscillatory fields can achieve atomic shot-noise level performance of 10^{-13}/sqrt(tau) for 10^6 atoms. The EIT signal can be detected with a heterodyne technique that provides noiseless gain; with this technique the optical phase shift of a 100 pW probe beam can be detected at the photon shot-noise level. Numerical calculations of the density matrix equations are used to identify realistic operating parameters at which AC Stark shifts are eliminated. By considering fluctuations in these parameters, we estimate that AC Stark shifts can be canceled to a level better than 2*10^{-14}. An overview of the apparatus is presented with estimates of duty cycle and power consumption.

Tunable axial potentials for atom-chip waveguides

We present a method for generating precise magnetic potentials that can be described by a polynomial series along the axis of a cold atom waveguide near the surface of an atom chip. With a single chip design consisting of several wire pairs, various axial potentials can be created by varying the ratio of the currents in the wires, including double wells, triple wells, and pure harmonic traps with suppression of higher order terms. We use this method to design and fabricate a chip with modest experimental requirements. Finally, we use the chip to demonstrate a double well potential.

Two-dimensional grating magneto-optical trap

We demonstrate a two dimensional grating magneto-optical trap (2D GMOT) with a single input beam and a planar diffraction grating in

A compact, moveable, microchip-based system for high repetition rate production of Bose-Einstein condensates

^{87}

Atom chip bose-einstein condensation in a portable vacuum cell

Rb. This configuration increases experimental access when compared with a traditional 2D MOT. As configured in the paper, the output flux is several hundred million rubidium atoms/s at a mean velocity of 19.0

A Wigner Function Approach to Coherence in a Talbot-Lau Interferometer

\pm~0.2

Ex vacuo atom chip Bose-Einstein condensate

m/s. The velocity distribution has a 3.3

Atom-chip Bose-Einstein condensation in a portable vacuum cell

\pm~1.7

Ultracold-Matter Systems

m/s standard deviation. We use the atomic beam from the 2D GMOT to demonstrate loading of a three dimensional grating MOT (3D GMOT) with

Channel cell system

2.02\times 10^8 \pm 3 \times 10^6