Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 7: Quantum Coherence and Quantum Information Systems II

TT 7.2: Talk

Monday, March 26, 2007, 14:15–14:30, H20

A 2D array of Cooper pair boxes as a candidate for a protected qubit — •Jörg-Hendrik Bach, Alexander Shnirman, and Gerd Schön — Institut für theoretische Festkörperphysik, Universität Karlsruhe, 76131-Karlsruhe

We consider a 2-dimensional array of double-island Cooper pair boxes as a candidate for a protected qubit. Two types of couplings are implemented in the array. These are inductive nearest-neighbour couplings along the array’s rows and capacitive nearest-neighbour couplings between the array’s columns. Projected onto the doubly degenerate ground states of the Cooper pair boxes the two couplings do not commute. Thus the system reduces effectively to an array of spin-1/2 particles with non-commuting row- and column couplings. This reminds of the system proposed by Doucot et al. [Phys. Rev. B 71, 024505 (2005)] in the context of protected quantum computing. Similarities and differences to this system are pointed out; furthermore, the influence of the third level of the Cooper pair box is investigated.