Schedule Mar 01, 2013
Optimal Control of Transmon Qubit Gates in the Presence of Decoherence
Michael Goerz (Univ. Kassel)

Authors: Michael Goerz, Daniel M. Reich, Alireza Shabani, Birgitta Whaley, and Christiane P. Koch

We consider two transmon qubits [1] coupled via a cavity bus [2]. The strong coupling of each qubit to the shared cavity modes provides an indirect interaction that can be used to implement a two-qubit gate. Describing the system numerically allows us to take into account an arbitrary number of qubit and cavity excitations. We use optimal control theory (OCT), specifically Krotov's method [3], to find microwave pulses that drive the full system in the desired way in the shortest possible amount of time. Modeling the system dynamics with a master equation in Lindblad form [4], we analyze the effect of decoherence on the feasibility of high-fidelity two-qubit gates. OCT can then specifically select pathways robust to the influence of decoherence.

[1] J. Koch et. al., Phys. Rev. A 76, 042319 (2007)

[2] J. Majer et. al., Nature 449, 443 (2007)

[3] D. M. Reich et. al., J. Chem. Phys. 136, 104103 (2012)

[4] M. Boissonneault et. al. Phys. Rev. A 85, 022305 (2012)

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