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Noise and the Measurement Process for a Circular Josephson Array Qubit

Joachim Sjostrand·Anders Karlhede
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Abstract

We discuss a charge qubit consisting of a circular array of Josephson junctions. The two-level system we consider couples the two charge states through a higher order tunneling process thus making it possible to achieve a long relaxation time. Using the spin-boson Hamiltonian, we estimate decoherence due to ohmic as well as 1/f noise. We simulate the quantum mechanical measurement process by studing the density matrix of the qubit and a capacitively coupled single-electron transistor that measures the charge.

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Joachim Sjostrand, Anders Karlhede. 2003-04-23. Noise and the Measurement Process for a Circular Josephson Array Qubit. https://doi.org/10.1103/physrevb.69.024503

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