Physics – Quantum Physics
Scientific paper
2004-07-19
Physics
Quantum Physics
latex, 33 pages, domains of unbounded operators are now explicitly specified. Presentation more detailed. Implementing the shi
Scientific paper
10.1063/1.2142839
Every completely positive map G that commutes which the Hamiltonian time evolution is an integral or sum over (densely defined) CP-maps G_\sigma where \sigma is the energy that is transferred to or taken from the environment. If the spectrum is non-degenerated each G_\sigma is a dephasing channel followed by an energy shift. The dephasing is given by the Hadamard product of the density operator with a (formally defined) positive operator. The Kraus operator of the energy shift is a partial isometry which defines a translation on R with respect to a non-translation-invariant measure. As an example, I calculate this decomposition explicitly for the rotation invariant gaussian channel on a single mode. I address the question under what conditions a covariant channel destroys superpositions between mutually orthogonal states on the same orbit. For channels which allow mutually orthogonal output states on the same orbit, a lower bound on the quantum capacity is derived using the Fourier transform of the CP-map-valued measure (G_\sigma).
No associations
LandOfFree
Decomposition of time-covariant operations on quantum systems with continuous and/or discrete energy spectrum does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Decomposition of time-covariant operations on quantum systems with continuous and/or discrete energy spectrum, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Decomposition of time-covariant operations on quantum systems with continuous and/or discrete energy spectrum will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-535852