We present a compact, transportable system that produces Bose-Einstein condensates (BECs) near the surface of an integrated atom microchip. The system occupies a volume of 0.4 m 3 and operates at a repetition rate as high as 0.3 Hz. Evaporative cooling in a chip trap with trap frequencies of several kHz leads to nearly pure condensates containing 1.9×10 4 87 Rb atoms. Partial condensates are observed at a temperature of 1.58(8) µK, close to the theoretical transition temperature of 1.1 µK.Since the first experimental demonstrations of BoseEinstein condensation (BEC) in a gas of neutral atoms, 1-3 studies of BEC and related forms of ultracold matter have been largely motivated by purely scientific interests. The complexity and size of the required apparatus necessitate that these experiments remain confined to research laboratories. However it has become increasingly evident that ultracold matter can play a utilitarian role in applications such as atomic clocks, inertial sensors, and electric and magnetic field sensing.4-9 Indeed, much of the work on ultracold atom chip technology is predicated on the need for compact systems that can find their way out of the laboratory and into the field.We present here a compact, movable, microchip-based BEC production system that occupies a volume of 0.4 m 3 , operates at a repetition rate as high as 0.3 Hz, and produces BECs containing 1.9×10 4 atoms in the |F = 2, m F = 2 ground state of 87 Rb (see Fig. 1). The system contains all of the components needed to produce and image BECs, including an ultra-high vacuum (UHV) system, lasers, data acquisition hardware, electronics, and imaging equipment. The system can be easily reconfigured for use with atom chips having unique wire patterns designed for different applications. As such, it can serve as a standardized platform for a variety of portable experiments that utilize ultracold matter.
The three 2(3)P fine structure intervals of 4H are measured at an improved accuracy that is sufficient to test two-electron QED theory and to determine the fine structure constant alpha to 14 parts in 10(9). The more accurate determination of alpha, to a precision higher than attained with the quantum Hall and Josephson effects, awaits the reconciliation of two inconsistent theoretical calculations now being compared term by term. A low pressure helium discharge presents experimental uncertainties quite different than for earlier measurements and allows direct measurements of light pressure shifts.
We present an experimental apparatus that produces Bose-Einstein condensates (BECs) of 87 Rb atoms at a rate of 1 Hz. As a demonstration of the system's ability to operate continuously, 30 BECs were produced and imaged in 32.1 s. Without imaging, a single BEC could be produced in 953 ms. The system uses an atom chip to confine atoms in a dimple trap with frequencies exceeding 1 kHz. With this tight trap, the duration of evaporative cooling can be reduced to less than 0.5 s. Using principal component analysis, insight into the largest sources of noise and drift was obtained by extracting the dominant contributions to the variance. The system utilizes a compact physics package that can be integrated with lasers and electronics to create a transportable ultracold-atom device for applications outside of a laboratory environment.
We present a set of building blocks for constructing and utilizing compact, microchip-based, ultrahigh vacuum (UHV) chambers for the practical deployment of cold-and ultracold-atom systems. We present two examples of chip-compatible approaches for miniaturizing UHV chambers-double-magneto-optical-trap cells and channel cells-as well as compact, free-space optical systems into which these cells can be easily inserted and quickly swapped. We discuss progress in atom chip technology, including miniature through-chip electrical feedthroughs and optical windows for transferring light between the trapping region on the chip and the ambient environment. As an example of the latter, we present some of the first through-chip fluorescence images of a Bose-Einstein condensate. High numerical apertures can be achieved with this technique, allowing for submicron resolution. Whether for optical detection, trapping, or control, such fine resolution will have numerous applications in quantum information, especially for experiments based on ultracold atoms trapped in optical lattices.123 976 E. A. Salim et al.
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