Over the last decade there has been a continuing interest in slow and stored light based on the electromagnetically
induced transparency (EIT) effect, because of their potential applications in quantum information manipulation.
However, previous experimental works all dealt with the single-component slow light which cannot be employed as a
qubit. In this work, we report the first experimental demonstration of two-component or spinor slow light (SSL) using a
double tripod (DT) atom-light coupling scheme. The oscillations between the two components, similar to the Rabi
oscillation of a two-level system or a qubit, were observed. Single-photon SSL can be considered as two-color qubits.
We experimentally demonstrated a possible application of the DT scheme as quantum memory and quantum rotator for
the two-color qubits. This work opens up a new direction in the slow light research.
We explore the optical flux lattices produced for ultra-cold atoms in the radiation field when both the atom-light
coupling and the detuning exhibit an oscillatory behavior. We analyze not only the magnetic flux but also the
geometric vector potential generating the flux, as well as the accompanying geometric scalar potential. We show
how to deal with the gauge-dependent singularities of the Aharonov-Bohm (AB) type appearing in the vector
potentials for the optical flux lattices. We present a way to calculate the continuous magnetic flux through the
elementary cell via the singularities of the vector potential inside the cell. The analysis is illustrated with a
square optical flux lattice. We present a way of creating such a lattice using the Raman transitions induced by
a set of properly chosen polarization-dependent standing waves propagating at a right angle and containing a
time-phase difference.
We study laser induced spin-orbit (SO) coupling in cold atom systems where lasers couple three internal states
to a pair of excited states, in a double tripod topology. Proper choice of laser amplitudes and phases produces a
Hamiltonian with a doubly degenerate ground state separated from the remaining "excited" eigenstates by gaps
determined by the Rabi frequencies of the atom-light coupling. After eliminating the excited states with a Born-
Oppenheimer approximation, the Hamiltonian of the remaining two states includes Dresselhaus (or equivalently
Rashba) SO coupling. Unlike earlier proposals, here the SO coupled states are the two lowest energy "dressed"
spin states and are thus immune to collisional relaxation. Finally, we discuss a specific implementation of our
system using Raman transitions between different hyperfine states within the electronic ground state manifold
of nuclear spin I = 3/2 alkali atoms.
The properties of localised dipole emitters in the form of a quantum dot or a colour centre embedded in a crystal
environment can be drastically modified by a change in the composition, size and shape of the environment in
which the emitter is embedded. Thanks to recent advances in material deposition techniques and lithography,
as well as the advances in detection techniques and optical manipulation, experimental work is now capable of
revealing a new range of physical phenomena when the typical dimensions are of the order of an optical dipole
transition wavelength and below. These advances have arisen at a time of a heightened research effort devoted to
the important goal of identifying a qubit and a suitable environment that forms the basis for a scalable hardware
architecture for the practical realisation of quantum information processing. A physical system that we have
recently put forward as a candidate for such a purpose involves localised emitters in the form of quantum dots
or colour centres embedded in a nanocrystal. This suggestion became more persuasive following the success of
experiments which, for the first time, were able to demonstrate quantum cryptography using a nitrogen vacancy
in a diamond nanocrystal as a single-photon source. It has, however, been realised that a more versatile scenario
could be achieved by making use of the interplay between dielectric cavity confinement and dipole orientation.
Besides position dependence the main properties exhibit strong dipole orientational dependece suggesting that the
system is a possible candidate as a qubit for a scalable hardward architecture for quantum information processing.
Cavity confinement can control processes since it can lead to the enhancement and the complete suppression of
the de-excitation process, with further control provided by the manipulation of the dipole orientation by optical
means. This article is concerned with the modelling of quantum processes for quantum systems localised in
artificially fabricated structures made of high conductivity metals and dielectric cavities. The essential features
of cavity field confinement in this context are presented and the effects on de-excitation rates are assessed.
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