Parametrically Activated Entangling Gates Using Transmon Qubits
Sam Caldwell, Nicolas Didier, Colm A. Ryan, Eyob Alebachew Sete, A. Hudson, Peter J. Karalekas, Riccardo Manenti, Marcus P. da Silva, R. Sinclair, Ezer Acala, Nasser Alidoust, Jorge Angeles, Andrew J. Bestwick, Maxwell Block, Benjamin J. Bloom, A. Bradley, Cong Dang Bui, Lauren Capelluto, Rick Chilcott, Jeff Cordova · Physical Review Applied · 2018
A central challenge in building a scalable quantum computer with superconducting qubits is the execution of high-fidelity two-qubit gates in the presence of many resonant elements. As more elements are added to the architecture, and as the multiplicity of their couplings grows, the design's frequency space becomes crowded, and performance suffers. The authors present a way to address this difficulty: selective activation of interactions between transmon qubits of fixed frequency and those of tunable frequency. This activation depends on both the amplitude and frequency of modulation, and using the amplitude as an additional condition for resonance alleviates frequency crowding.