Macroscopic resonant tunneling in an rf-SQUID flux qubit under a single-cycle sinusoidal driving ^*

Abstract

We experimentally demonstrate the observation of macroscopic resonant tunneling (MRT) phenomenon of the macroscopic distinct flux states in a radio frequency superconducting quantum interference device (rf-SQUID) under a singlecycle sinusoidal driving. The population of the qubit exhibits interference patterns corresponding to resonant tunneling peaks between states in the adjacent potential wells. The dynamics of the qubit depends significantly on the amplitude, frequency, and initial phase of the driving signal. We do the numerical simulations considering the intra-well and interwell relaxation mechanism, which agree well with the experimental results. This approach provides an effective way to manipulate the qubit population by adjusting the parameters of the external driving field.

Geometrical representation of coherent tunneling process in two-waveguide and three-waveguide coupler

“…Landau-Zener (LZ) non-adiabatic tunneling process and stimulated Raman adiabatic passage (STIRAP) have different physical mechanisms and have aroused wide interest during the past two decades. For instance, the former has been widely used in waveguide arrays, [1,2] electron transfer on insulating surface, [3] Bose-Einstein condensate, [4,5] Bose-Fermi mixture, [6] optical lattices, [7] radio frequency superconducting quantum interference, [8] preparation of quantum state, [9] coherent destruction of tunneling, [10] to name a few, while the latter has been used in waveguide optics, [11][12][13] population transfer in atomic and molecular physics, [14][15][16][17][18] Bose-Einstein condensate, [19,20] generation of terahertz pulses, [21] optical storage, [22] and so forth. Shore et al have discussed the differences between the STIRAP in three-level atom system and LZ tunneling process in four-state model.…”