1,260 research outputs found
Faithful teleportation with arbitrary pure or mixed resource states
We study faithful teleportation systematically with arbitrary entangled
states as resources. The necessary conditions of mixed states to complete
perfect teleportation are proved. Based on these results, the necessary and
sufficient conditions of faithful teleportation of an unknown state |\phi> in
C^d with an entangled resource {\rho} in C^m \otimes C^d and C^d \otimes C^n
are derived. It is shown that for {\rho} in C^m\otimesC^d, {\rho} must be a
maximally entangled state, while for {\rho} in C^d \otimes C^n, {\rho} must be
a puremaximally entangled state. Moreover, we show that the sender's
measurements must be all projectors of maximally entangled pure states. The
relations between the entanglement of the formation of the resource states and
faithful teleportation are also discussed.Comment: 9 page
Testing cosmic opacity from SNe Ia and Hubble parameter through three cosmological-model-independent methods
We use the newly published 28 observational Hubble parameter data ()
and current largest SNe Ia samples (Union2.1) to test whether the universe is
transparent. Three cosmological-model-independent methods (nearby SNe Ia
method, interpolation method and smoothing method) are proposed through
comparing opacity-free distance modulus from Hubble parameter data and
opacity-dependent distance modulus from SNe Ia . Two parameterizations,
and are adopted for the
optical depth associated to the cosmic absorption. We find that the results are
not sensitive to the methods and parameterizations. Our results support a
transparent universe.Comment: 11 pages, 8 figures, 1 table, PLB(in press
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