Coherent controlization using superconducting qubits

  1. Nicolai Friis,
  2. Alexey A. Melnikov,
  3. Gerhard Kirchmair,
  4. and Hans J. Briegel
Coherent controlization, i.e., coherent conditioning of arbitrary single- or multi-qubit operations on the state of one or more control qubits, is an important ingredient for the flexible
implementation of many algorithms in quantum computation. This is of particular significance when certain subroutines are changing over time or when they are frequently modified, such as in decision-making algorithms for learning agents. We propose a scheme to realize coherent controlization for any number of superconducting qubits coupled to a microwave resonator. For two and three qubits, we present an explicit construction that is of high relevance for quantum learning agents. We demonstrate the feasibility of our proposal, taking into account loss, dephasing, and the cavity self-Kerr effect.

Relativistic Quantum Teleportation with superconducting circuits

  1. Nicolai Friis,
  2. Antony R. Lee,
  3. Kevin Truong,
  4. Carlos Sabín,
  5. Enrique Solano,
  6. Göran Johansson,
  7. and Ivette Fuentes
We study the effects of relativistic motion on quantum teleportation and propose a realizable experiment where our results can be tested. We compute bounds on the optimal fidelity of
teleportation when one of the observers undergoes non-uniform motion for a finite time. The upper bound to the optimal fidelity is degraded due to the observer’s motion however, we discuss how this degradation can be corrected. These effects are observable for experimental parameters that are within reach of cutting-edge superconducting technology.