Transmon probe for quantum characteristics of magnons in antiferromagnets

  1. Vahid Azimi-Mousolou,
  2. Anders Bergman,
  3. Anna Delin,
  4. Olle Eriksson,
  5. Manuel Pereiro,
  6. Danny Thonig,
  7. and Erik Sjöqvist
The detection of magnons and their quantum properties, especially in antiferromagnetic (AFM) materials, is a substantial step to realize many ambitious advances in the study of nanomagnetism
and the development of energy efficient quantum technologies. The recent development of hybrid systems based on superconducting circuits provides the possibility of engineering quantum sensors that exploit different degrees of freedom. Here, we examine the magnon-photon-transmon hybridisation based on bipartite AFM materials, which gives rise to an effective coupling between a transmon qubit and magnons in a bipartite AFM. We demonstrate how magnetically invisible magnon modes, their chiralities and quantum properties such as nonlocality and two-mode magnon entanglement in bipartite AFMs can be characterized through the Rabi frequency of the superconducting transmon qubit.

Holonomic Quantum Computation via Adiabatic Shortcut

  1. J. Zhang,
  2. Thi Ha Kyaw,
  3. D.M. Tong,
  4. Erik Sjöqvist,
  5. and L. C. Kwek
Fast quantum gates based on geometric phases provide a platform for performing robust quantum computation. In particular, non-adiabatic holonomic quantum computation, which involves
non-Abelian geometric phases to achieve universality, has recently been demonstrated in several experiments. Here, we generalize the transitionless quantum driving algorithm to a degenerate Hilbert space, with which we propose a route towards fast holonomic quantum computation. We propose a proof-of-principle experiment in a superconducting circuit architecture to realize our scheme.