1995/04/01 by Benjamin Schumacher · 5 citations
Physics and Astronomy · Computer Science · #Quantum Mechanics and Applications #Quantum Information and Cryptography #Quantum Computing Algorithms and Architecture
paper · doi:10.1103/physreva.51.2738
openalex publication_date 1995/04/01 · openalex created_date 2022/05/11 · openalex updated_date 2026/08/03
A theorem is proven for quantum information theory that is analogous to the noiseless coding theorem of classical information theory. In the quantum result, the von Neumann entropy S of the density operator describing an ensemble of pure quantum signal states is equal to the number of spin-1/2 systems (``quantum bits'' or ``qubits'') necessary to represent the signal faithfully. The theorem holds whether or not the signal states are orthogonal. Related results are also presented about the fidelity of quantum coding and about representing entangled quantum states.