The work in this thesis falls into two broad categories: creating Bose-Einstein condensates (BECs) in compact and portable systems, and manipulating neutral atoms in small systems to facilitate a continuously running neutral Rydberg atom quantum computer. The work with BECs focused on the miniaturization of ultracold matter systems. Ultracold matter has potential uses in many practical applications, such as atomic clocks, inertial sensors, and electric and magnetic field sensing. Much of the potential of atom chip based systems relies on the ability for the system to make its way out of the lab. The BEC system created occupies a volume of 0.4m^3 and operates at a repetition rate as high as 0.3Hz, creating Rubidium BECs of around 20k atoms. The system contains all of the components needed to produce and image BECs, including the UHV system, lasers, data acquisition hardware, electronics, and imaging equipment. The system can be easily reconfigured for different applications simply by changing the atom chip. As such, the hope is that it can serve as a standardized platform for a variety of portable experiments that utilize ultracold matter. The quantum computing work focuses on the ongoing work in atom manipulation for neutral Rydberg atom quantum computing. Neutral Rydberg atom quantum computing has great potential and, by harnessing the tool kit developed working with cold atoms, has the potential of scalability and continuous operation. An entirely new laser system and vacuum cell was built to work with Cesium. We have currently built a state of the art vacuum cell and developed far-detuned optical trapping and transport techniques to facilitate continuous quantum computing. Ongoing efforts include optical lattice generation and single-atom manipulation and imaging.
We propose and present a quantitative analysis of neutral atom microtraps based on optical near fields produced by the diffraction of a laser wave on small apertures in a thin screen. We show that near-field atom microtraps are capable of storing atoms in micron-sized regions, with estimated trap lifetimes of about 1s, when using a moderate laser intensity of about 10W∕cm2. The depth of the proposed Fresnel atom microtraps is about 0.1mK. An array of such atom microtraps could have applications to site-selective manipulation of cold atoms.
The aim of this work is to study the dynamics of cold atoms trapped in a one-dimensional periodic lattice generated by an optical potential. Such a system is described by a standard model in condensed matter, namely the so-called Bose-Hubbard model. Arrays of cold neutral atoms or ions are the basic elements of some proposals of quantum computers, which motivates the interest of understanding their dynamics from a mathematical point of view. The main targets of this Master Thesis are the following. First, starting from a classical Hamiltonian of the Frenkel-Kontorova type and thanks to Perturbation Theory, to derive the discrete Bougolyubov-Gross-Pitaevskii (dBGP) equation. Second, starting from first principle formulation, to provide a systematic, quantum mechanical, perturbative derivation of the Bose-Hubbard (BH) model to orders higher than the first one in the small parameter.