2,307 research outputs found
Quantum computing with alkaline earth atoms
We present a complete scheme for quantum information processing using the
unique features of alkaline earth atoms. We show how two completely independent
lattices can be formed for the S and P states, with one used as
a storage lattice for qubits encoded on the nuclear spin, and the other as a
transport lattice to move qubits and perform gate operations. We discuss how
the P level can be used for addressing of individual qubits, and how
collisional losses from metastable states can be used to perform gates via a
lossy blockade mechanism.Comment: 4 pages, 3 figures, RevTeX
Unitary -designs via random quenches in atomic Hubbard and Spin models: Application to the measurement of R\'enyi entropies
We present a general framework for the generation of random unitaries based
on random quenches in atomic Hubbard and spin models, forming approximate
unitary -designs, and their application to the measurement of R\'enyi
entropies. We generalize our protocol presented in [Elben2017:
arXiv:1709.05060, to appear in Phys. Rev. Lett.] to a broad class of atomic and
spin lattice models. We further present an in-depth numerical and analytical
study of experimental imperfections, including the effect of decoherence and
statistical errors, and discuss connections of our approach with many-body
quantum chaos.Comment: This is a new and extended version of the Supplementary material
presented in arXiv:1709.05060v1, rewritten as a companion paper. Version
accepted to Phys. Rev. A. Minus sign corrected in Eq (5
Ground State Laser Cooling Beyond the Lamb-Dicke Limit
We propose a laser cooling scheme that allows to cool a single atom confined
in a harmonic potential to the trap ground state . The scheme assumes
strong confinement, where the oscillation frequency in the trap is larger than
the effective spontaneous decay width, but is not restricted to the Lamb-Dicke
limit, i.e. the size of the trap ground state can be larger than the optical
wavelength. This cooling scheme may be useful in the context of quantum
computations with ions and Bose-Einstein condensation.Comment: 6 pages, 4 figures, to appear in Europhysics Letter
Continuous Observation of Interference Fringes from Bose Condensates
We use continuous measurement theory to describe the evolution of two Bose
condensates in an interference experiment. It is shown how the system evolves
in a single run of the experiment into a state with a fixed relative phase,
while the total gauge symmetry remains unbroken. Thus, an interference pattern
is exhibited without violating atom number conservation.Comment: 4 pages, Postscrip
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