Flux Quantum Lab

The Flux Quantum Lab (Φ₀) is an experimental condensed matter physics lab at the Young Team Incubator in the Physics Institute, Collège de France, Paris.

Research

We are developing a sensitive Josephson junction based spectrometer operating from 2-1500 GHz that can be coupled on-chip to mesoscopic systems. The spectrometer will be used to measure high frequency electronic properties of superconducting atomic ontacts, graphene, topological insulators/superconductors, and other samples. In superconducting atomic contacts, the goal is measuring the lifetime of quasiparticles and Andreev pairs. In graphene, the question is whether pristine samples are gapped at the Dirac point. In topological materials, the goal is detecting Majorana modes spectroscopically.

See Research for more details.

Why Φ₀?

The magnetic flux quantum, Φ₀ = h/2e, combines Planck's constant h and the electron charge e and embodies the research conducted in the group: we explore quantum properties of electrons in mesoscopic systems.

The flux quantum appears in two relevant physical contexts:

  1. Flux quantization: the magnetic flux threading a superconducting ring can only be multiples of the flux quantum.
  2. AC Josephson effect: in a voltage biased Josephson junction, the constant of proportionality relating the voltage to the frequency of emitted radiation is the flux quantum.

These phenomena are the foundation for the Josephson junction spectrometer.

Images

Funding

This research is supported by an ERC Starting Grant, an IDEX grant ANR-10-IDEX-0001-02 PSL, and the Paris Emergence Program of the City of Paris.