Koch helped introduce the transmon and fluxonium, superconducting circuit designs that address charge noise while preserving the controllable quantum behavior needed for computation.
Northwestern UniversityarXiv / Physical Review AarXiv / ScienceKoch’s contributions show how circuit design can reduce a physical obstacle to quantum computing. The transmon paper identifies an operating regime that strongly suppresses sensitivity to charge noise while retaining enough nonlinearity for qubit control. The fluxonium work uses a different circuit structure to manage offset charges. Both arose from collaborations and are linked here to their original research. Together they illustrate the role of theoretical modeling in choosing hardware that experiments can build and control.
Northwestern UniversityarXiv / Physical Review AarXiv / ScienceDefining contributions
Work, in context- 2007
Introducing the transmon
As first author, Koch introduced the transmon with a team of superconducting-circuit researchers. The design reduces charge sensitivity by increasing the ratio of Josephson to charging energy while retaining sufficient anharmonicity for selective control.
First author of the transmon paper; the circuit proposal was developed collaboratively.
Source-supported recordarXiv / Physical Review A - 2009
Cocreating fluxonium
With Vladimir Manucharyan, Leonid Glazman and Michel Devoret, Koch reported fluxonium: a small junction shunted by a large inductance made from a junction array. The circuit addresses offset-charge sensitivity while retaining discrete, anharmonic energy levels.
Coauthor with Vladimir Manucharyan, Leonid Glazman and Michel Devoret of the fluxonium paper.
Source-supported recordarXiv / Science
Follow the evidence
3 sourcesPrimary papers, institutional records and attributed announcements. Each source supports the claims linked above.
- Northwestern Universityinstitutional profile
Jens Koch
Current professor identification and superconducting-circuit research.
Checked 2026-09-19 - arXiv / Physical Review Aresearch paper
Charge insensitive qubit design derived from the Cooper pair box
First authorship and transmon design tradeoffs.
Published 2007-02-28 · Checked 2026-09-19 - arXiv / Scienceresearch paper
Fluxonium: single Cooper pair circuit free of charge offsets
Authorship, circuit construction and offset-charge result.
Published 2009-06-04 · Checked 2026-09-19