title: Ultrafast quantum gates in circuit QED.
abstract: We present a method to implement ultrafast two-qubit gates valid for the ultrastrong coupling and deep strong coupling regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics technology. Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of the intracavity field, operating at a time proportional to the inverse of the resonator frequency. Through ab initio calculations, we show that these quantum gates can be performed at subnanosecond time scales while keeping a fidelity above 99%.
authors.affiliation: Departamento de Química Física, Universidad del País Vasco UPV/EHU, Apartado 644, 48080 Bilbao, Spain.
authors.forename: G
authors.initials: G
authors.lastname: Romero
authors.forename: D
authors.initials: D
authors.lastname: Ballester
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
authors.forename: V
authors.initials: V
authors.lastname: Scarani
authors.forename: E
authors.initials: E
authors.lastname: Solano