This thesis presents the first experimental demonstration of a two-wire AC Zeeman trap on an atom chip. The AC Zeeman energy is a resonant, bipolar, state-dependent atomic energy shift produced by alternating magnetic fields with frequencies near hyperfine transitions. We demonstrate that high gradients in this energy, as near an atom chip, can produce a spin-state selective force greater than gravity for ultracold rubidium atoms. Our novel trap is generated by a local minimum in AC Zeeman energy. Using less than one watt of power, we demonstrate trap frequency on the order of a few hundred Hz, trap depth about 5 μK, and quarter-second lifetimes. Motivated by trapped atom interferometry, this proof of principle AC Zeeman trap can also augment atom and ion experiments as a dynamic spin-dependent potential. Different parameters in the current arrangement can produce regions of linear gradient, flat saddle points, square- and donut-shaped traps, offering a new set of tools for atom chip experiments. This thesis also presents the relevant dressed atomic theory, four AC Zeeman trap designs, Rabi frequency measurements, numerical trap simulations, and the AC skin effect in wide rectangular wires.

A cryogenic hydrogen maser has been designed and constructed which will operate at temperatures near 10 K with a surface of frozen neon in the atom storage region. The atom storage region and microwave cavity are made from three pieces of single crystal sapphire. The neon surface is expected to be isothermal and stable to within 1 mK during operation. The sapphire is contained within a copper enclosure which is surrounded by magnetic shields and cooled by conduction to a helium-cooled copper plate. The helium cooling to the plate is in the form of cold helium gas flowing through a tube attached to the plate. A transition region made of G-11 fiberglass connects the sapphire cavity to the area containing the state-selection magnet. The internal vacuum of the maser is maintained by a helium-cooled cryopump located between the hydrogen atom source and the transition. Atomic hydrogen is supplied by an effusive discharge operated at liquid nitrogen temperatures. Much of the expected thermal characteristics have been experimentally verified. At temperatures near 10 K a stability of 1 mK was achieved for periods exceeding ninety minutes. Operation of the maser as a self-sustained oscillator awaits final tuning of the microwave cavity and development of the techniques required to prepare the neon surface.

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The electric dipole moment of the ground state of cesium, d$\sb{\rm Cs}$, is measured. This result is related to the electric dipole moment of the electron in a straightforward way using the results of atomic theory calculations found in the literature. The resulting limit of the electric dipole moment of the electron represents a stringent test of time reversal invariance. Cesium vapor is studied at zero magnetic field in glass cells which also contain 250 torr of nitrogen. The ground state of cesium is optically pumped by a laser beam and the atomic orientation undergoes the electrical analog of Larmor precession due to an applied electric field. The precession is detected by comparing the transmission rates of left and right circularly polarized light for a second laser beam which is orthogonal to both the initial laser beam and the applied electric field. The Hamiltonians H = $\vec\mu\cdot\vec B$ and H = $\vec d\cdot\vec E$ are interchangeable allowing calibration of the apparatus using an applied magnetic field. During data acquisition all three components of the effective magnetic field are reduced below 100 nG. Comparing signals from two cells with opposite electric fields eliminates signals due to drifts in the homogeneous magnetic field. Comparing the signals from four cells, two with electric fields and two without, reduces noise due to fluctuating magnetic fields to about 150 pG in 20 seconds of integration (a single data point.) The precession frequency is determined with a statistical precision of 0.5 $\mu$Hz in a two day data collection run. A set of 13 data runs, 9 in the two cell configuration and 4 in the four cell configuration, is used to place upper limits d$\sb{\rm Cs}$ $<$ 1.1 $\times$ 10$\sp{-24}$e-cm, d$\sb{\rm e}$ $<$ 9.3 $\times$ 10$\sp{-27}$e-cm and a limit on T-violating electron-nucleon scaler interactions of C$\sb{\rm S}$ $<$ 10$\sp{-5}\rm G\sb{\rm F}$. This limit represents an order of magnitude improvement over the previously limits on d$\sb{\rm Cs}$ and constrains theories attempting to explain the violation of CP invariance which is seen in the K meson system.

Optical frequency standards offer the possibility of a step improvement of up to two orders of magnitude in the accuracy with which the SI second can be realised. ¹⁷¹Yb⁺ possesses two dipole-forbidden optical transitions that are promising candidates for a redefinition of the second. In this thesis, absolute frequency measurements of these two transitions are presented. A number of experimental upgrades have been implemented, which have resulted in a large reduction in both the statistical and systematic uncertainties associated with the measurements and have improved both the reliability and simplicity of the experimental setup. In particular, the replacement of two frequency-doubled Ar⁺-pumped Ti:sapphire lasers with extended cavity diode lasers has eliminated the downtime associated with their maintenance. Additionally, the introduction of polarisation modulation on the cooling light has allowed the residual bias magnetic field required for laser cooling to be reduced by a factor of thirty. The first measurement at the National Physical Laboratory (NPL) of the frequency of the ²S_1/2 (F = 0) → ²D_3/2 (F′ = 2) electric quadrupole (E2) transition at 436 nm is presented. The transition frequency was measured against a hydrogen maser using a femtosecond optical frequency comb, and was determined with a relative standard uncertainty of 1.3 × 10⁻¹⁴. A commercial diode-based laser system was then implemented in order to drive the ²S_1/2 (F = 0) → ²F_7/2 (F′ = 3) electric octupole (E3) transition at 467 nm. The laser frequency was actively stabilised to the ultra-narrow atomic absorption with a resolved linewidth of 11 Hz, allowing the acquisition of ninety hours of frequency data measured relative to the NPL’s primary frequency standard CsF2. Combined with a thorough evaluation of the systematic perturbations, the total fractional uncertainty in the absolute frequency of the transition has been reduced by a factor of twenty to 1 × 10⁻¹⁵. Recent complementary results from Physikalisch-Technische Bundesanstalt (PTB) show that the E3 transition in ¹⁷¹Yb⁺ has the potential to be a highly accurate and reproducible optical frequency standard, and to date these measurements demonstrate the best international agreement between trapped ion optical frequency standards.

Desde o desenvolvimento de técnicas para controlar o movimento atômico usando a força de pressão de radiação, muitas aplicações tem sido sugeridas e implementadas. Entre estas, o aprisionamento atômico e o desenvolvimento de estruturas espaciais com átomos frios merece atenção especial devido à sua potencial aplicação em depósitos superficiais como litografia. Realizamos, neste trabalho, um estudo sobre feixes atômicos e sua desaceleração e compressão espacial. Realizamos também estudos numéricos sobre a formação de estruturas em anéis em feixes atômicos, verificando ser factível, e estudando também a compressão destas estruturas espaciais, com vistas a possíveis aplicações em nanolitografia atômica. / From the very beginning of the development of atomic motion control techniques using the radiation pressure force, a variety of applications have been suggested and implemented. Of all these, atomic trapping techniques and the development of spatial structures using cold atoms deserves special attention due to its potential application to surface deposition such as lithography. In the present work, we perform a study on atomic beams and their deceleration and spatial compression. We also perform numerical studies and present experimental observation of the realization of spatial ring structures in atomic beams, verifying its factibility, and we study the compression of such ring-shaped structures with application in atomic nanolithography as the ultimate goal.