The implementation of hybrid codes and nuclear magnetic resonance quantum information processing
The development of quantum error correcting techniques is of paramount importance to the ultimate goal of implementing practical quantum computers. The simultaneous transmission of quantum and classical information over a quantum channel was initially investigated by Shor and since been continued by others. It was shown that there is an advantage to transmitting both quantum and classical information simultaneously, compared to independent transmissions. The characterization and construction of codes that allow to transmit both quantum and classical information, which we refer to as hybrid codes, was done from a coding theory perspective and by using the operator algebra quantum error correction (OAQEC) perspective. In this work we unify these two perspectives, showing that the coding theory formulation is a specific case of the OAQEC perspective. As a result we generalized the quantum hamming bound to the hybrid case. To date no such hybrid codes have been physically implemented. Nuclear magnetic resonance (NMR) quantum information processors (QIP) have been an excellent test bed for quantum computing. The techniques of NMR had been refined for many years and can now be applied to quantum computing. NMR techniques provides a high degree of qubit control and long decoherence times compared to other QIP. These two properties of NMR QIP make it a prime candidate for implementing hybrid codes. In this work we developed a hybrid code and designed the circuit for encoding it. We used Matlab to simulate the pulse sequence which would be used in an NMR QIP to carry out the encoding of the hybrid circuit. According to those simulations the full encoding, a single qubit Pauli error and a full decoding can be carried out without the effects of decoherence destroying the quantum information beyond retrieval.