Quantum Wires and Quantum Dots for Neutral Atoms

We propose a new class of nanoscale electro-optical traps for neutral atoms. A prototype is the toroidal trap created by a suspended, charged carbon nanotube decorated with a silver nanosphere dimer. An illuminating laser field, blue detuned from an atomic resonance frequency, is strongly focused by plasmons induced in the dimer and generates both a repulsive potential barrier near the nanostructure surface and a large viscous damping force that facilitates trap loading. Atom...

We propose a scalable neutral atom quantum computer with an on-demand interaction. Artificial lattice of near field optical traps is employed to trap atom qubits. Interactions between atoms can be turned off if the atoms are separated by a high enough potential barrier so that the size of the atomic wave function is much less than the interatomic distance. One-qubit gate operation is implemented by a gate control laser beam which is attached to an individual atom. Two-qubit g...

Neutral atoms trapped by laser light are amongst the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) c...

We describe the realization of atom-optical elements as magnetic waveguide potentials, beam splitters and gravitational traps on a microchip. The microchip was produced by electroplating gold conductors on an aluminium-oxide substrate. The conductors are 30-150 $\mu$m wide and allow for the generation of waveguides at large distances to the chip surface, where surface effects are negligible. We show that these elements can be integrated on a single chip to achieve complex ato...

We fabricate a miniature spherical mirror for tightly focusing an optical dipole trap for neutral atoms. The mirror formation process is modelled to predict the dimensions for particular fabrication parameters. We integrate the spherical mirror with a neutral atom experiment to trap and detect a single atom with high efficiency. The mirror serves the dual purpose of focusing the dipole trap as well as collection of the atomic fluorescence into an optical fibre.

Remarkable progress towards realizing quantum computation has been achieved using natural and artificial atoms as qubits. This article presents a brief overview of the current status of different types of qubits. On the one hand, natural atoms (such as neutral atoms and ions) have long coherence times, and could be stored in large arrays, providing ideal "quantum memories". On the other hand, artificial atoms (such as superconducting circuits or semiconductor quantum dots) ha...

We propose an optical dipole trap for cold neutral atoms based on the electric field produced from the evanescent fields in a hollow rectangular slot cut through an optical nanofibre. In particular, we discuss the trap performance in relation to laser-cooled rubidium atoms and show that a far off-resonance, blue-detuned field combined with the attractive surface-atom interaction potential from the dielectric material forms a stable trapping configuration. With the addition of...

The progress achieved in micro-fabricating potential for cold atoms has defined a new field in quantum technology - Atomtronics - where a variety of 'atom circuits' of very different spatial shapes and depth have been devised for atom manipulation, with a precision that nowadays is approaching that of lithographic techniques. Atomtronic setups are characterized by enhanced flexibility and control of the fundamental mechanisms underlying their functionalities and by the reduce...

By tightly focussing a laser field onto a single cold ion trapped in front of a far-distant dielectric mirror, we could observe a quantum electrodynamic effect whereby the ion behaves as the optical mirror of a Fabry-P\'erot cavity. We show that the amplitude of the laser field is significantly altered due to a modification of the electromagnetic mode structure around the atom in a novel regime in which the laser intensity is already changed by the atom alone. e propose a dir...

The subject of this review are atom traps based on optical dipole forces in laser fields, along with their unique features as storage devices at ultralow energies. The basic physics of the dipole interaction is discussed, and the experimental background of dipole trapping experiments is explained. Specific trapping schemes and experiments are presented, where the wide range of applications of dipole traps is explored considering particular examples.