Resonant effects in a SQUID qubit subjected to non adiabatic changes
Abstract
By quickly modifying the shape of the effective potential of a double SQUID flux qubit from a single-well to a double-well condition, we experimentally observe an anomalous behavior, namely an alternance of resonance peaks, in the probability to find the qubit in a given flux state. The occurrence of Landau-Zener transitions as well as resonant tunneling between degenerate levels in the two wells may be invoked to partially justify the experimental results. A quantum simulation of the time evolution of the system indeed suggests that the observed anomalous behavior can be imputable to quantum coherence effects. The interplay among all these mechanisms has a practical implication for quantum computing purposes, giving a direct measurement of the limits on the sweeping rates possible for a correct manipulation of the qubit state by means of fast flux pulses, avoiding transitions to non-computational states.
Keywords
Cite
@article{arxiv.1310.5491,
title = {Resonant effects in a SQUID qubit subjected to non adiabatic changes},
author = {F. Chiarello and S. Spilla and M. G. Castellano and C. Cosmelli and A. Messina and R. Migliore and A. Napoli and G. Torrioli},
journal= {arXiv preprint arXiv:1310.5491},
year = {2015}
}
Comments
6 pages and 6 figures. The paper, as it is, has been accepted for publication on PRB on March 2014