Fluxonium: Single Cooper-Pair Circuit Free of Charge Offsets

Manucharyan, Vladimir E.
Koch, Jens
Glazman, Leonid I.
Devoret, Michel H.

Departments of Physics and Applied Physics, Yale University, New Haven, CT 06520, USA.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material

www.sciencemag.org/cgi/content/full/326/5949/113/DC1

Materials and Methods

SOM Text

Fig. S1

Table S1

References

29 April 2009; accepted 28 July 2009

10.1126/science.1175552

Science 326(5949):p 113-116, October 2, 2009.

The promise of single Cooper-pair quantum circuits based on tunnel junctions for metrology and quantum information applications is severely limited by the influence of offset charges: random, slowly drifting microscopic charges inherent in many solid-state systems. By shunting a small junction with the Josephson kinetic inductance of a series array of large-capacitance tunnel junctions, thereby ensuring that all superconducting islands are connected to the circuit by at least one large junction, we have realized a new superconducting artificial atom that is totally insensitive to offset charges. Yet its energy levels manifest the anharmonic structure associated with single Cooper-pair effects, a useful component for solid-state quantum computation.