Cavity-based reservoir engineering for Floquet engineered superconducting circuits

  1. Francesco Petiziol,
  2. and André Eckardt
By periodically driving a quantum system at a high frequency, it can acquire novel properties that are captured by an effective time-independent Hamiltonian. An important application
of such Floquet engineering is, e.g., the realization of effective gauge fields for charge-neutral particles. Here we consider driven Bose-Hubbard systems, as they can be realized as arrays of artificial atoms in superconducting circuits, and show that the ground state of the effective Hamiltonian can be prepared with high fidelity using reservoir engineering. For this purpose, some artificial atoms are coupled to driven leaky cavities. We derive an effective description of the open system by employing degenerate perturbation theory in the extended Floquet space with respect to both the periodic drive and the system-cavity coupling. Applying this theory to different Floquet-engineered flux ladders, we find both that it allows to cool the systems and that it shows excellent agreement with the full driven-dissipative evolution of system and cavities.

Accelerating adiabatic protocols for entangling two qubits in circuit QED

  1. Francesco Petiziol,
  2. Benjamin Dive,
  3. Stefano Carretta,
  4. Riccardo Mannella,
  5. Florian Mintert,
  6. and Sandro Wimberger
We introduce a method to speed up adiabatic protocols for creating entanglement between two qubits dispersively coupled to a transmission line, while keeping fidelities high and maintaining
robustness to control errors. The method takes genuinely adiabatic sweeps, ranging from a simple Landau-Zener drive to boundary cancellation methods and local adiabatic drivings, and adds fast oscillations to speed up the protocol while cancelling unwanted transitions. We compare our protocol with existing adiabatic methods in a state-of-the-art parameter range and show substantial gains. Numerical simulations underline that this strategy is efficient also beyond the rotating-wave approximation, and that the method is robust against random biases in the control parameters.