2,376 research outputs found
Experimental Bell Inequality Violation with an Atom and a Photon
We report the measurement of a Bell inequality violation with a single atom
and a single photon prepared in a probabilistic entangled state. This is the
first demonstration of such a violation with particles of different species.
The entanglement characterization of this hybrid system may also be useful in
quantum information applications.Comment: 4 pages, 2 figure
Zero-Point cooling and low heating of trapped 111Cd+ ions
We report on ground state laser cooling of single 111Cd+ ions confined in
radio-frequency (Paul) traps. Heating rates of trapped ion motion are measured
for two different trapping geometries and electrode materials, where no effort
was made to shield the electrodes from the atomic Cd source. The low measured
heating rates suggest that trapped 111Cd+ ions may be well-suited for
experiments involving quantum control of atomic motion, including applications
in quantum information science.Comment: 4 pages, 6 figures, Submitted to PR
Sympathetic Cooling of Trapped Cd+ Isotopes
We sympathetically cool a trapped 112Cd+ ion by directly Doppler-cooling a
114Cd+ ion in the same trap. This is the first demonstration of optically
addressing a single trapped ion being sympathetically cooled by a different
species ion. Notably, the experiment uses a single laser source, and does not
require strong focusing. This paves the way toward reducing decoherence in an
ion trap quantum computer based on Cd+ isotopes.Comment: 4 figure
Preparing encoded states in an oscillator
Recently a scheme has been proposed for constructing quantum error-correcting
codes that embed a finite-dimensional code space in the infinite-dimensional
Hilbert space of a system described by continuous quantum variables. One of the
difficult steps in this scheme is the preparation of the encoded states. We
show how these states can be generated by coupling a continuous quantum
variable to a single qubit. An ion trap quantum computer provides a natural
setting for a continuous system coupled to a qubit. We discuss how encoded
states may be generated in an ion trap.Comment: 5 pages, 4 figures, RevTe
Yang-Lee Zeros of the Q-state Potts Model on Recursive Lattices
The Yang-Lee zeros of the Q-state Potts model on recursive lattices are
studied for non-integer values of Q. Considering 1D lattice as a Bethe lattice
with coordination number equal to two, the location of Yang-Lee zeros of 1D
ferromagnetic and antiferromagnetic Potts models is completely analyzed in
terms of neutral periodical points. Three different regimes for Yang-Lee zeros
are found for Q>1 and 0<Q<1. An exact analytical formula for the equation of
phase transition points is derived for the 1D case. It is shown that Yang-Lee
zeros of the Q-state Potts model on a Bethe lattice are located on arcs of
circles with the radius depending on Q and temperature for Q>1. Complex
magnetic field metastability regions are studied for the Q>1 and 0<Q<1 cases.
The Yang-Lee edge singularity exponents are calculated for both 1D and Bethe
lattice Potts models. The dynamics of metastability regions for different
values of Q is studied numerically.Comment: 15 pages, 6 figures, with correction
Decoherence in ion traps due to laser intensity and phase fluctuations
We consider one source of decoherence for a single trapped ion due to
intensity and phase fluctuations in the exciting laser pulses. For simplicity
we assume that the stochastic processes involved are white noise processes,
which enables us to give a simple master equation description of this source of
decoherence. This master equation is averaged over the noise, and is sufficient
to describe the results of experiments that probe the oscillations in the
electronic populations as energy is exchanged between the internal and
electronic motion. Our results are in good qualitative agreement with recent
experiments and predict that the decoherence rate will depend on vibrational
quantum number in different ways depending on which vibrational excitation
sideband is used.Comment: 2 figures, submitted to PR
Abelian Sandpile Model on the Husimi Lattice of Square Plaquettes
An Abelian sandpile model is considered on the Husimi lattice of square
plaquettes. Exact expressions for the distribution of height probabilities in
the Self-Organized Critical state are derived. The two-point correlation
function for the sites deep inside the Husimi lattice is calculated exactly.Comment: 12 pages, LaTeX, source files and some additional information
available at http://thsun1.jinr.dubna.su/~shcher
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