For a real number r > 0, let F(r) be the family of all stationary ergodic quantum sources with von Neumann entropy rates less than r. We prove that, for any r > 0, there exists a blind, source-inde...
For a real number r>0, let F(r) be the family of all stationary ergodic quantum sources with von Neumann entropy rates less than r. We prove that, for any r>0, there exists a blind, source-independent block compression scheme which compresses every source from F(r) to rn qubits per input block length~n with arbitrarily high fidelity for all large n.}As our second result, we show that the stationarity and the ergodicity of a quantum source \rho_m_{m=1}^{\infty} are preserved by any trace-preserving completely positive linear map of the tensor product form {\cal E}^{\otimes m}, where a copy of {\cal E} acts locally on each spin lattice site. We also establish ergodicity criteria for so called classically-correlated quantum sources.
For a real number r > 0, let F(r) be the family of all stationary completely ergodic quantum sources with von Neumann entropy rates less than r. We prove that, for any r > 0, there exists a blind, source-independent block compression scheme which compresses every source from F(r) to rn qubits per input block length n with arbitrarily high fidelity for all large n. As our second result, we show that the stationarity and the ergodicity of a quantum source {ρm}m=1∞ are preserved by any trace-preserving completely positive linear map of the tensor product form ε⊗m, where a copy of ε acts locally on each spin lattice site. We also establish ergodicity criteria for so called classically-correlated quantum sources.
Suppose that a finite dimensional quantum source is known to have von Neumann entropy less than or equal to S but is otherwise completely unspecified. We describe a method of universal quantum data compression which will faithfully compress the quantum information of any such source to S qubits per signal (in the limit of large block lengths).
We investigate the recently introduced notion of smooth Renyi entropy for the case of ergodic information sources, thereby generalizing previous work which concentrated mainly on i.i.d. information sources. We will actually consider ergodic quantum information sources, of which ergodic classical information sources are a special case. We prove that the average smooth Renyi entropy rate will approach the entropy rate of a stationary, ergodic source, which is equal to the Shannon entropy rate for a classical source and the von Neumann entropy rate for a quantum source.