Superinductance for very long-lived quantum coherence
Research Project , 2013 – 2014

I will develop a “superinductor” – a very-high kinetic inductance superconducting nanowire of thin-film niobium nitride. Its reactive impedance will exceed the quantum resistance (6.5 kΩ) at microwave frequencies, while being nearly lossless at dc. I shall first make this new component, and then design a new type of superconducting qubit (quantum bit of information) – the “metastable flux qubit” – consisting of a nanoscale Josephson junction (JJ) shunted by a superinductance.

This qubit has a very small transition dipole matrix element between its metastable quantum ground states, and therefore extremely small coupling to any noise sources. This enables a projected energy-relaxation coherence time approaching one second – more than three orders of magnitude better than any existing device. Since decoherence is the worst problem impeding the advancement of quantum-information processing (QIP) technology, the successful realization of this long-lived qubit would represent a breakthrough in superconducting quantum engineering.


Jonas Bylander (contact)

Associate Professor at Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics



Funding Chalmers participation during 2013–2014

Related Areas of Advance and Infrastructure

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Areas of Advance

Nanofabrication Laboratory




Nanowire Superinductors

Licentiate thesis

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