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.

Digital quantum simulators in a scalable architecture of hybrid spin-photon qubits

  1. Alessandro Chiesa,
  2. Paolo Santini,
  3. Dario Gerace,
  4. James Raftery,
  5. Andrew A. Houck,
  6. and Stefano Carretta
Resolving quantum many-body problems represents one of the greatest challenges in physics and physical chemistry, due to the prohibitively large computational resources that would be
required by using classical computers. A solution has been foreseen by directly simulating the time evolution through sequences of quantum gates applied to arrays of qubits, i.e. by implementing a digital quantum simulator. Superconducting circuits and resonators are emerging as an extremely-promising platform for quantum computation architectures, but a digital quantum simulator proposal that is straightforwardly scalable, universal, and realizable with state-of-the-art technology is presently lacking. Here we propose a viable scheme to implement a universal quantum simulator with hybrid spin-photon qubits in an array of superconducting resonators, which is intrinsically scalable and allows for local control. As representative examples we consider the transverse-field Ising model, a spin-1 Hamiltonian, and the two-dimensional Hubbard model; for these, we numerically simulate the scheme by including the main sources of decoherence. In addition, we show how to circumvent the potentially harmful effects of inhomogeneous broadening of the spin systems.