Quantum rate-distortion theory for i.i.d. sources

Using a natural distortion measure based on entanglement fidelity and allowing unrestricted classical side-information, we find the exact quantum rate-distortion function for a source of isotropic qubits. An upper bound, that we believe to be exact, is found in the case of biased sources. We also establish that rate-distortion codes that are optimal with respect to entanglement fidelity produce no entropy exchange with the environment of any individual qubit.