Dynamic Matter-Wave Pulse Shaping

In this paper we discuss possibilities to manipulate a matter-wave with time-dependent potentials. Assuming a specific setup on an atom chip, we explore how one can focus, accelerate, reflect, and stop an atomic wave packet, with, for example, electric fields from an array of electrodes. We also utilize this method to initiate coherent splitting. Special emphasis is put on the robustness of the control schemes. We begin with the wave packet of a single atom, and extend this to a BEC, in the Gross-Pitaevskii picture. In analogy to laser pulse shaping with its wide variety of applications, we expect this work to form the base for additional time-dependent potentials eventually leading to matter-wave pulse shaping with numerous application

Using time reversal symmetry for sensitive incoherent matter-wave Sagnac interferometry

We present a theory of the transmission of incoherent guided matter-waves through Sagnac interferometers. Interferometer configurations with only one input and one output port have a property similar to the phase rigidity observed in the transmission through Aharonov-Bohm interferometers in coherent mesoscopic electronics. This property is connected to the existence of counterpropagating paths of equal length and enables the operation of such matter-wave interferometers with incoherent sources. High finesse interferometers of this kind have a rotation sensitivity inversely proportional to the square root of the finesse

Coupling between internal spin dynamics and external degrees of freedom in the presence of colored noise

We observe asymmetric transition rates between Zeeman levels (spin-flips) of magnetically trapped atoms. The asymmetry strongly depends on the spectral shape of an applied noise. This effect follows from the interplay between the internal states of the atoms and their external degrees of freedom, where different trapped levels experience different potentials. Such insight may prove useful for controlling atomic states by the introduction of noise, as well as provide a better understanding of the effect of noise on the coherent operation of quantum systems.Comment: 5 pages, 4 figures; accepted to PR

Programmable trap geometries with superconducting atom chips

We employ the hysteretic behavior of a superconducting thin film in the remanent state to generate different traps and flexible magnetic potentials for ultra-cold atoms. The trap geometry can be programmed by externally applied fields. This new approach for atom-optics is demonstrated by three different trap types realized on a single micro-structure: a Z-type trap, a double trap and a bias field free trap. Our studies show that superconductors in the remanent state provide a new versatile platform for atom-optics and applications in ultra-cold quantum gases

Analysis of a Magnetically Trapped Atom Clock

We consider optimization of a rubidium atom clock that uses magnetically trapped Bose condensed atoms in a highly elongated trap, and determine the optimal conditions for minimum Allan variance of the clock using microwave Ramsey fringe spectroscopy. Elimination of magnetic field shifts and collisional shifts are considered. The effects of spin-dipolar relaxation are addressed in the optimization of the clock. We find that for the interstate interaction strength equal to or larger than the intrastate interaction strengths, a modulational instability results in phase separation and symmetry breaking of the two-component condensate composed of the ground and excited hyperfine clock levels, and this mechanism limits the clock accuracy.Comment: 11 pages, 6 figures. Accepted for publication in Phys. Rev.

Organized Current Patterns in Disordered Conductors

We present a general theory of current deviations in straight current carrying wires with random imperfections, which quantitatively explains the recent observations of organized patterns of magnetic field corrugations above micron-scale evaporated wires. These patterns originate from the most efficient electron scattering by Fourier components of the wire imperfections with wavefronts along the $\pm 45^{\circ}$ direction. We show that long range effects of surface or bulk corrugations are suppressed for narrow wires or wires having an electrically anisotropic resistivity

One-mirror Fabry-Perot and one-slit Young interferometry

We describe a new and distinctive interferometry in which a probe particle scatters off a superposition of locations of a single free target particle. In one dimension, probe particles incident on superposed locations of a single "mirror" can interfere as if in a Fabry-Perot interferometer; in two dimensions, probe particles scattering off superposed locations of a single "slit" can interfere as if in a two-slit Young interferometer. The condition for interference is loss of orthogonality of the target states and reduces, in simple examples, to transfer of orthogonality from target to probe states. We analyze experimental parameters and conditions necessary for interference to be observed.Comment: 5 pages, 2 figures, RevTeX, submitted to PR

Observation of decoherence with a movable mirror

Recently it has been proposed to use parity as a measure of the mechanism behind decoherence or the transformation from quantum to classical. Here, we show that the proposed experiment is more feasible than previously thought, as even an initial thermal state would exhibit the hypothesized symmetry breaking.Comment: Proceedings of the Lake Garda "quantum puzzles" conferenc

A Pulse Shaping Algorithm of a Coherent Matter Wave. Controlling Reaction Dynamics

A pulse shaping algorithm for a matter wave with the purpose of controlling a binary reaction has been designed. The scheme is illustrated for an Eley-Rideal reaction where an impinging matter-wave atom recombines with an adsorbed atom on a metal surface. The wave function of the impinging atom is shaped such that the desorbing molecule leaves the surface in a specific vibrational state.Comment: 4 pages, 5 figure