Quantum metrology

The general goal of quantum metrology research is to revise the International System of Units in such a way that every unit in the SI is defined in terms of a fundamental constant of nature or using properties of individual atoms. The units of electrical quantities can be linked with two constants of nature - elementary charge (e) and Planck's constant (h) - using quantum standards. The quantum standard of voltage is based on Josephson effect that can be observed in superconductor structures, and researchers are presently working to extend the method from DC to AC. The quantum standard of resistance is based on the quantum Hall effect observable in 2-dimensional electron gas at low temperatures and high magnetic fields, and use of graphene for this purpose is under active research. Realization of the quantum standard of electric current by pumping single electrons one by one through a nanostructure is an active field of research internationally. MIKES focuses mainly on developing so-called SINIS turnstile that is a nanostructure consisting of superconducting electrodes and a small normal-metal island through which single electrons can be transported in a controllable way. The main goal is the closure of the so-called quantum metrological triangle that will test consistency between the quantum standards of voltage, current, and resistance, at relative uncertainty of 0.1 parts per million (ppm) or lower.

Research of MIKES in electrical quantum metrology:

  • Quantum metrological triangle
  • Quantum ampere: Realization of the new SI ampere
  • Detection of microwave photons using a SINIS nanostructure
  • Josephson-effect-based quantum standard for alternating voltage
  • Applications of Josephson effect in impedance metrology
  • Quantum standard for sampled electrical measurements
  • Graphene in resistance metrology

Collaborators

  • Aalto University / O.V. Lounasmaa Laboratory
  • Aalto University / Department of Micro- and Nanosciences
  • Physikalisch-Technische Bundesanstalt PTB​