Physics Research Seminar: Mircea Trif (International Research Centre MagTop, Poland)

Welcome to join us for a research seminar by Mircea Trif!

Title: Quantum computing with magnetic impurities in superconductors

Abstract:
Magnetic impurities in s-wave superconductors provide a viable platform for realising a topological quantum computer based on Majorana zero modes. However, the coherent manipulation of quantum degrees of freedom in these systems remains an open challenge. In this talk, I will  introduce a new type of quantum bit, a Yu-Shiba-Rusinov qubit (YSRQ), stemming from two nearby magnetic impurities on a superconductor, and demonstrate that the coherent rotation and the read out of the qubit states is possible by
exploiting the dynamics of the impurity spins. I will describe a protocol for inducing  Rabi oscillations and discuss the YSRQ robustness against environmental noise. The precession of the magnetic impurities also induces a feedback torque acting on the impurity, which in turn modifies its resonance frequency depending on the YSRQ state. I will show how this effect could be utilised to read out the YSRQ via the well established
STM-ESR techniques. In the last part of the talk I will briefly discuss an alternative approach for the YSRQ manipulation and detection based on supercurrents and, finally, a scheme for integrating YSRQs with topological Majorana qubits that could facilitate their fusion.

Host: Jose Lado