),
M. Siegel2 (
), and
S. V. Vyshenski1 (
)1Nuclear Physics Institute, Moscow State University, 119992 Moscow, Russia.
2Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany.
),
M. Siegel2 (
), and
S. V. Vyshenski1 (
)Macroscopically controlled wave function rearrangement and subsequent non-destructive readout of information in a system of quantum wells in heterostructures was discussed in [1]. This approach could have served as a base for non-dissipative quantum digital and analog devices [2] provided technologically realizable quantum dots in heterostuctures had high enough values of error-free trap time.
A new technological realization of Josephson weak links, namely with inctlusion of ferromagnetic material, is under extensive studied [3-7]. This approach leads to very unusual Josephson effect. In particular, the current - phase relation of the link becomes essentially non-sinusoidal, and its general form strongly depends of technologically controlled parameters. In the present paper we study properties of a ferromagnetic Josephson system which is analogus to the rf-SQUID built of conventional Josephson junctions. We show that its possible to build a nanostructure which has energy - phase diagram with 3 gaps. Well depts and separating barriers of the structure could be macrospopically and dynamically controled in wide ranges by applied rf magnetic field, which makes this structure a perfectly suitable candidate for non-dissipative quantum devices [2].
The proposed structure in analogous to the system used in [8] to give experimental evidence for a coherent superposition of macroscopically distinct flux states in an rf-SQUID. In our case we have additional macroscopically controllable parameters, and more rich dynamics, as 3 stable states are interacting.
References: