2011/01/14 by Alexander B. Zorin, Yuriy Makhlin · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevb.83.224506
published as Phys. Rev. B 83 (2011) 224506 · 6 pages
arxiv created 2011/01/14 · arxiv updated 2015/03/17
We propose a threshold detector with an operation principle, based on a parametric period-doubling bifurcation in an externally pumped nonlinear resonance circuit. The ac-driven resonance circuit includes a dc-current-biased Josephson junction ensuring parametric frequency conversion (period-doubling bifurcation) due to its quadratic nonlinearity. A sharp onset of oscillations at the half-frequency of the drive allows for detection of small variations of an effective inductance and, therefore, the read-out of the quantum state of a coupled Josephson qubit. The bifurcation characteristics of this circuit are compared with those of the conventional Josephson bifurcation amplifier, and its possible advantages are discussed.