One of the most significant requirements for realizing qubits is the ability to manipulate them coherently and retain coherence over an extended period of time. This becomes particularly challenging at the atomic scale due to many-body environments and the limited means for protecting the states from decoherence. Different scenarios have been realized, such as atomic spin systems on an insulating decoupling layer or atomic Yu-Shiba-Rusinov (YSR) states protected by a superconducting gap. Manipulating atomic scale spin systems with microwaves has spawned the new field of electron spin resonance spectroscopy combined with scanning tunneling microscopy (ESR-STM), which has made exciting advances over the past years. Coherent behavior in YSR states and manipulating YSR states with microwaves is challenging due to the parity protection. I will discuss our recent progress in manipulating atomic scale systems with microwaves and the challenges of maintaining coherence.

Please contact phweb@ust.hk should you have questions about the talk.