Environment-assisted Cross-Resonance gate

Superconducting qubits have emerged to become a promising platform for quantum computing [1]. A cross-resonance (CR) gate is a particularly important two-qubit gate, which enables operation of CNOT. In CR gate, two qubits, the so-called control and target, are coupled and the control qubit is driven at frequency of the target qubit [2,3,4]. However, the operation of these gates is affected by their environment [5]. To quantify this effect, we consider a Cross-Resonance (CR) gate connected to external reservoirs and evaluate the entangling interaction.

[1] J. Clarke, F. Wilhelm, Superconducting quantum bits, Nature453, 1031–1042 (2008)

[2] Xuexin Xu, M.H. Ansari, ZZ freedom in two qubit gates, Phys.Rev. Applied 15, 064074 (2021), arXiv:2009.00485

[3] Jaseung Ku, Xuexin Xu, Markus Brink, David C. McKay, JaredB. Hertzberg, Mohammad H. Ansari, B.L.T. Plourde, Suppression of Unwanted ZZ Interactions in a Hybrid Two-Qubit System, Phys.Rev. Lett. 125, 200504 (2020), arXiv:2003.02775

[4] Xuexin Xu, M. Ansari, Parasitic-Free Gate: An Error-ProtectedCross-Resonance Switch in Weakly Tunable Architectures, Phys.Rev. Applied 19, 024057, arXiv:2212.05519

[5] Radhika H. Joshi, Mohammad H. Ansari, Environment-assisted Cross-Resonance gate, In preparation.