Polarization-Based Quantum Key Distribution Without Shared Reference Frame
by
Jean Christian Boileau
Institute for Quantum Computing, Physics Departement, University of Waterloo, 200 university Avenue West, Waterloo, ON N2L 3G1, Canada.
Coauthors: Daniel Gottesman, Raymond Laflamme, Martin Laforest, Casey Myers, David Poulin, Rob Spekkens

Experimentalists attempting to perform QKD over long distances must deal with inherent noise from optical fibers. If we neglect attenuation and assume that the coherence time of the photon is large enough, the noise in the fiber can be represented as a time-dependent rotation of the polarization states. To overcome this problem, some techniques have been explored: using an operational system to systematically compensate the error, encoding the qubits in the phase of the photons or sending the photon back and forth through the fiber with the help of a Faraday mirror. I will talk about some new alternate solutions based on decoherence-free subspace. I will relate them to the problem of implementing quantum cryptography without a shared reference frame.

Date received: March 10, 2004