Optimal condition for a cavity QED-based fault-tolerant quantum computation

Cavity quantum electrodynamics (QED) has been extensively studied for decades as one of the promising candidates for the realization of quantum computing and quantum network. For example, the controlled phase flip gate between photons assisted by cavity-QED systems was proposed in 2004[1] and demonstrated recently[2]. However, fault-tolerant quantum computing is still difficult because of the infidelity and the losses originated from imperfections of the cavity QED system.
In this work, we theoretically investigate optimal conditions for the cavity-QED-based quantum gate. Controllable experimental parameters are optimized not only to suppress photon loss considered in previous study[3] but also to increase fidelity. As a result, the experimental conditions for achieving the fault-tolerant threshold is much relaxed compared to the previous one. We finally derive the error and loss probability in the optimal condition assuming the typical experimental values of the nanofiber cavity-QED system as a promising candidate for the near future development[4].

[1]L.-M. Duan and H. J. Kimble, Phys. Rev. Lett. 92, 127902 (2004).
[2]B. Hacker et al., Nature 536, 193 (2016).
[3]H. Goto and K. Ichimura, Phys. Rev. A 82, 032311 (2010).
[4]S. Kato and T. Aoki, Phys. Rev. Lett. 115, 093603 (2015).