Right-sizing fluxonium against charge noise

@article{Mizel2019RightsizingFA,
  title={Right-sizing fluxonium against charge noise},
  author={Ari Mizel and Yariv Yanay},
  journal={arXiv: Quantum Physics},
  year={2019}
}
We analyze the charge-noise induced coherence time $T_2$ of the fluxonium qubit as a function of the number of array junctions in the device, $N$. The pure dephasing rate decreases with $N$, but we find that the relaxation rate increases, so $T_2$ achieves an optimum as a function of $N$. This optimum can be much smaller than the number typically chosen in experiments, yielding a route to improved fluxonium coherence and simplified device fabrication at the same time. 
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