HYBRID DECOHERENCE-FREE ERROR-CORRECTING CODES VIA QUANTUM TRAJECTORIES

摘要

Generalizing a proposal by Alber et al. (quant-ph/0103042), we develop a hybrid decoherence-free subspace (DFS) quantum error-correcting code (QECC) approach, utilizing the methodology of quantum trajectories. The DFS acts as a first layer of protection against errors due to the conditional evolution, while the QECC acts as a second layer and uses the DFS encoding to offer protection against random quantum jumps. We also study the effect of incorporation of quantum logic gates and hence the possibility of fault tolerant quantum computation. Finally we give an example of the method in cavity QED systems.