16,349 research outputs found
Entanglement between two fermionic atoms inside a cylindrical harmonic trap
We investigate quantum entanglement between two (spin-1/2) fermions inside a
cylindrical harmonic trap, making use of the von Neumann entropy for the
reduced single particle density matrix as the pure state entanglement measure.
We explore the dependence of pair entanglement on the geometry and strength of
the trap and on the strength of the pairing interaction over the complete range
of the effective BCS to BEC crossover. Our result elucidates an interesting
connection between our model system of two fermions and that of two interacting
bosons.Comment: to appear in PR
Quantum spin mixing in a binary mixture of spin-1 atomic condensates
We study quantum spin mixing in a binary mixture of spin-1 condensates
including coherent interspecies mixing process, using the familiar spinor
condensates of Rb and Na atoms in the ground lower hyperfine F=1
manifolds as prototype examples. Within the single spatial mode approximation
for each of the two spinor condensates, the mixing dynamics reduce to that of
three coupled nonlinear pendulums with clear physical interpretations. Using
suitably prepared initial states, it is possible to determine the interspecies
singlet-pairing as well as spin-exchange interactions from the subsequent
mixing dynamics.Comment: 6 pages, 3 figure
Creating maximally entangled atomic states in a Bose-Einstein condensate
We propose a protocol to create maximally entangled pairs, triplets,
quartiles, and other clusters of Bose condensed atoms starting from a
condensate in the Mott insulator state. The essential element is to drive
single atom Raman transitions using laser pulses. Our scheme is simple,
efficient, and can be readily applied to the recent experimental system as
reported by Greiner {\it et al.} [ Nature {\bf 413}, 44 (2002)].Comment: 4 pages, 2 figures. revised version as to be publishe
Entanglement and spin squeezing properties for three bosons in two modes
We discuss the canonical form for a pure state of three identical bosons in
two modes, and classify its entanglement correlation into two types, the
analogous GHZ and the W types as well known in a system of three
distinguishable qubits. We have performed a detailed study of two important
entanglement measures for such a system, the concurrence and the
triple entanglement measure . We have also calculated explicitly the spin
squeezing parameter and the result shows that the W state is the most
``anti-squeezing'' state, for which the spin squeezing parameter cannot be
regarded as an entanglement measure.Comment: 7 pages, 6 figures; corrected figure sequence. Thanks to Dr. Han P
A conditional quantum phase gate between two 3-state atoms
We propose a scheme for conditional quantum logic between two 3-state atoms
that share a quantum data-bus such as a single mode optical field in cavity QED
systems, or a collective vibrational state of trapped ions. Making use of
quantum interference, our scheme achieves successful conditional phase
evolution without any real transitions of atomic internal states or populating
the quantum data-bus. In addition, it only requires common addressing of the
two atoms by external laser fields.Comment: 8 fig
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