5,731 research outputs found
Non Abelian structures and the geometric phase of entangled qudits
In this work, we address some important topological and algebraic aspects of
two-qudit states evolving under local unitary operations. The projective
invariant subspaces and evolutions are connected with the common elements
characterizing the su(d) Lie algebra and their representations. In particular,
the roots and weights turn out to be natural quantities to parametrize cyclic
evolutions and fractional phases. This framework is then used to recast the
coset contribution to the geometric phase in a form that generalizes the usual
monopole-like formula for a single qubit.Comment: 22 pages, LaTe
Fractional topological phase for entangled qudits
We investigate the topological structure of entangled qudits under unitary
local operations. Different sectors are identified in the evolution, and their
geometrical and topological aspects are analyzed. The geometric phase is
explicitly calculated in terms of the concurrence. As a main result, we predict
a fractional topological phase for cyclic evolutions in the multiply connected
space of maximally entangled states.Comment: REVTex, 4 page
Spin-orbit mode transfer via a classical analog of quantum teleportation
We translate the quantum teleportation protocol into a sequence of coherent
operations involving three degrees of freedom of a classical laser beam. The
protocol, which we demonstrate experimentally, transfers the polarisation state
of the input beam to the transverse mode of the output beam. The role of
quantum entanglement is played by a non-separable mode describing the path and
transverse degrees of freedom. Our protocol illustrates the possibility of new
optical applications based on this intriguing classical analogue of quantum
entanglement.Comment: 5 pages, 7 figure
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