Nonequilibrium Dynamics And Landau-Zener-StüCkelberg-Majorana Interference In A Gate-Tunable Nanowire

Hybrid semiconductor-superconductor systems can hold quasiparticle excitations,known as Andreev bound states（ABSs）in the superconducting energy gap.With the emergence of topological superconductivity,a zero-energy ABS with exotic qualities,known as Majorana bound state（MBS）,has been discovered.MBSs,as a non-Abelian anyon,is considered as the most promising candidate for topological quantum computation.However,because MBSs is similar to many trivial states in experimental phenomena,most of the phenomena observed so far do not fully support the existence of MBSs.ABSs,as a prototype of MBSs,is very similar to MBSs.Therefore,clarifying the distinction between the two has also attracted a tremendous interest from researchers.Before the first part of this paper is published,tunneling experiments have been limited to studying ABSs at equilibrium.The theory indicates that the DOS of ABSs will split and broaden under nonequilibrium.The nonequilibrium dynamics of ABSs and Kondo effects are studied for the first time in josephson quantum dots based on In As_0.85Sb_0.15nanowires.Through tunneling spectroscopy,we demonstrated a full picture of the nonequilibrium dynamic splitting and broadening of ABSs,which interplays with the nonequilibrium Kondo DOS,and Kondo enhanced zero-bias conductance peaks（ZBCPs）.Our discovery provides experimental evidence of nonequilibrium dynamics of ABSs,and also provides a relevant comparison to benchmark the Majorana signal in future experiments.One of the advantages of the hybrid semiconductor-superconductor nanowires systems is the full gate tunability.Through the gate voltage,Josephson junction can be tuned from macroscopic quantum coherence to microscopic particle,and multiple coherent transport mechanisms can coexist.Josephson junctions based on epitaxial Aluminum In As_0.92Sb_0.08 nanowires,which is directly coupled with the external environment,is an open system,so the decoherence time is short.So far,the decoherence time of the variety of charges has not been examined in an open system,and even experimental proposals are elusive.In this work,variety of coherent tunneling processes in Josephson junctions are investigated using Landau-Zener-Stückelberg-Majorana（LZSM）interferometry.These include Cooper pairs,multi-charges through multiple Andreev reflections（MARs）and single-charges.Most importantly,for the first time,we extracted the coherence time of all these charges in the Fourier space of the interference fringes and observed the transition from the macroscopic coherence of the Cooper pair to the microscopic particle coherence.The LZSM interference also provides a unified description for all the charge transfer processes in ultra-small JJs under fast driving.