Atom Interferometers

Interference with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory fields technique used in atomic clocks. Atom interferometry is now reaching maturity as a powerful art with many applications in modern science. In this review we first describe the basic tools for coherent atom optics including diffraction by nanostructures and laser light, three-grating interferometers, and double wells on AtomChips. Then we review scientific advances in a broad range of fields that have resulted from the application of atom interferometers. These are grouped in three categories: (1) fundamental quantum science, (2) precision metrology and (3) atomic and molecular physics. Although some experiments with Bose Einstein condensates are included, the focus of the review is on linear matter wave optics, i.e. phenomena where each single atom interferes with itself.Comment: submitted to Reviews of Modern Physic

Quantum metrology with nonclassical states of atomic ensembles

Quantum technologies exploit entanglement to revolutionize computing, measurements, and communications. This has stimulated the research in different areas of physics to engineer and manipulate fragile many-particle entangled states. Progress has been particularly rapid for atoms. Thanks to the large and tunable nonlinearities and the well developed techniques for trapping, controlling and counting, many groundbreaking experiments have demonstrated the generation of entangled states of trapped ions, cold and ultracold gases of neutral atoms. Moreover, atoms can couple strongly to external forces and light fields, which makes them ideal for ultra-precise sensing and time keeping. All these factors call for generating non-classical atomic states designed for phase estimation in atomic clocks and atom interferometers, exploiting many-body entanglement to increase the sensitivity of precision measurements. The goal of this article is to review and illustrate the theory and the experiments with atomic ensembles that have demonstrated many-particle entanglement and quantum-enhanced metrology.Comment: 76 pages, 40 figures, 1 table, 603 references. Some figures bitmapped at 300 dpi to reduce file siz

Simulating infinite vortex lattices in superfluids: a novel scheme and its applications

This thesis is mostly based on the research presented in [1, 2, 3]. We introduce a novel efficient framework to treat infinite periodic vortex lattices in rotating superfluids under a mean-field Gross-Pitaevskii description. In doing so, we introduce a generalisation of the Fourier transform which correctly diagonalises the kinetic energy terms while respecting the required twisted boundary conditions. We call this integral transform a Magnetic Fourier transform. Testing the method, we re-obtain known results in the lowest-Landau-level regime, and further extend to stronger interacting regimes. We provide an extension of the above method to treat multicomponent systems, demonstrating that new degrees of freedom need to be introduced for each new component. We then employ this method to investigate the ground states of binary superfluid systems whose constituents have equal masses, thereby extending previous work carried out in the lowest-Landau-level limit to arbitrary interactions within Gross-Pitaevskii theory. In particular, we find that the interactions depauperate the phase diagram, with only the triangular lattice phase surviving in the limit of strong interactions. Withal we prove this applies regardless of the mass ratio of the constituents. We further investigate binary superfluid systems with non unitary mass ratios, obtaining a range of novel and exotic vortex lattice configurations. Finally we derive a linear relation which accurately describes the phase boundaries in the strong interaction regime.Open Acces

Characterization of Trap Frequencies for Cold Atom Laboratory Bose-Einstein Condensates

With the recent production of Bose-Einstein condensates using NASA\u27s Cold Atom Laboratory (CAL) aboard the International Space Station, research is underway focusing on the extent to which quantum mechanics can be studied in a microgravity environment. These condensates have the potential to be the coldest ever studied in experiment and in free-fall their place in orbit allows us to observe them in long time-of-flights. This thesis reports fitting analyses and trap frequency characterization of imaging data from condensates in conventional magnetic potentials. This information will be used for the calibration and design of future experiments with CAL, regarding both conventional and radio-frequency dressed traps. Of particular interest to further study are ellipsoidal shell condensates and the quasi-two-dimensional condensate that exists on its surface in the limit of low shell thickness

Making, probing and understanding Bose-Einstein condensates

Contribution to the proceedings of the 1998 Enrico Fermi summer school on Bose-Einstein condensation in Varenna, Italy.Comment: Long review paper with ~90 pages, ~20 figures. 2 GIF figures in separate files (4/5/99 fixed figure

Dynamics of bright solitary matter-waves

This thesis describes the formation of a 85Rb Bose-Einstein condensate and the subsequent creation of a bright solitary matter-wave in a quasi-one-dimensional optical waveguide, with experiments investigating the dynamics of a solitary wave in comparison with a repulsive Bose-Einstein condensate. In the final chapters of this thesis, progress towards the interaction of a solitary wave with a narrow barrier and an attractive atom-surface potential is presented. Beyond the above, a review of recent soliton and solitary wave theory is presented from the perspective of an experimentalist, culminating in the numerical analysis of a variety of key areas, namely, quantum reflection, solitary wave size and solitary wave profile. The modelling and experimental results relating to the merging of ultracold gases of 85Rb and 87Rb, in order to create isotopic mixtures, is also described within this thesis. Such a scheme could be used as an initial step in the process of forming molecules or undertaking sympathetic cooling. Finally, the creation of a complex LabVIEW based experimental control system is also described within