5 research outputs found
Entanglement generation in double- system
In this paper, we study the generation of entanglement in a double-
system. Employing standard method of laser theory, we deduce the dynamic
evolution equation of the two-mode field. We analyze the available entanglement
criterion for double- system and the condition of entanglement
existence. Our results show that under proper parameters, the two-mode field
can entangled and amlified
Truncated su(2) moment problem for spin and polarization states
We address the problem whether a given set of expectation values is
compatible with the first and second moments of the generic spin operators of a
system with total spin j. Those operators appear as the Stokes operator in
quantum optics, as well as the total angular momentum operators in the atomic
ensemble literature. We link this problem to a particular extension problem for
bipartite qubit states; this problem is closely related to the symmetric
extension problem that has recently drawn much attention in different contexts
of the quantum information literature. We are able to provide operational,
approximate solutions for every large spin numbers, and in fact the solution
becomes exact in the limiting case of infinite spin numbers. Solutions for low
spin numbers are formulated in terms of a hyperplane characterization, similar
to entanglement witnesses, that can be efficiently solved with semidefinite
programming.Comment: 18 pages, 1 figur