Quantum and Classical Noise in Practical Quantum Cryptography Systems Based on Polarization-Entangled Photons
Stefania Castelletto, Ivo P. Degiovanni, M L. Rastello
Quantum cryptography key distribution (QCKD) experiments have been recently based on polarization entangled photons. However, in any practical realization, quantum systems suffer from either unwanted or induced interactions with the environment and the quantum measurement system, showing up as quantum and, ultimately, statistical noise. In thispaper, we investigate how ideal polarization entanglement in spontaneous parametric down conversion (SPDC) undergoes quantum noise in its practical implementation as secure quantum system, yielding errors in the transmitted bit sequence.Since all SPDC-based QCKD schemes rely on the measurement of coincidence to assert the bit transmission between the two parties, we bundle up the overall quantum and statistical noise in an exhaustive model to calculate the accidental coincidences. This model predicts precisely the quantum bit error rate and the sifted key and allows comparisons between different security criteria of the hitherto proposed QCKD protocols, resulting in an objective assessment of performances and advantages of different systems.
Physical Review A (Atomic, Molecular and Optical Physics)
, Degiovanni, I.
and Rastello, M.
Quantum and Classical Noise in Practical Quantum Cryptography Systems Based on Polarization-Entangled Photons, Physical Review A (Atomic, Molecular and Optical Physics)
(Accessed June 3, 2023)