Quantum Detection and Coding with Applications to Quantum Cryptography

Isaac L. Chuang, Raymond Laflamme

Recent progress in quantum cryptography and quantum computers has given hope to their imminent practical realization. An essential element at the heart of the application of these quantum systems is a quantum error correction scheme. We propose a new technique based on the use of coding in order to detect and correct errors due to imperfect transmission lines in quantum cryptography or memories in quantum computers. We give a particular example of how to detect a decohered qubit in order to transmit or preserve with high fidelity the original qubit.

Narayanankutty Karuppath

ARTUR K. EKERT

Liu Bi-chen

Quantum key distribution is one of the most primary application in quantum information. Quantum cryptography of Slot extractive sercret key is a new coding system that uses the time of photons arrived at de- tector as the quantum information, and use the slot of detected photons selecting the key. It is also analysed that principle and the main characteristics of the photons-coding system ,and the experiment scheme and the key problem is introduced.

Philippe B. Gallion

Mitsuru Hamada

A conjugate code pair is defined as a pair of linear codes such that one contains the dual of the other. The conjugate code pair represents the essential structure of the corresponding Calderbank-Shor-Steane (CSS) quantum code. It is argued that conjugate code pairs are applicable to quantum cryptography in order to motivate studies on conjugate code pairs.