Dynamics of some single flux quantum devices: I. Parametric quantron

Abstract

In this paper and the following one, the properties of two systems operating with single flux quanta are calculated. The first system is a quantron (a one-junction interferometer) with a Josephson gate as a junction. By a proper change of its critical current in time, the switching of quantron stable states can be controlled by a small external flux much less than Φ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</inf> . This "Parametric Quantron" can be used as the basic cell of a Single Quantum Logic System. The most wonderful property of this device is that the energy dissipation during one logical step (PτT factor) can be much less than the thermal energy K <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</inf> T and is limited by quantum effects only: Pτ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> \simg10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> h.