Dr. Thomas Weissl- Nanostructure Physics, Department of Applied Physics, KTH
TBA
Time: Thu 2015-10-22 09.00 - 11.00
Location: FA31
Participating: Dr. Thomas Weissl
Title: Metrology with Josephson and phase-slip junctions
Abstract:
Frequency can be measured with the highest precision, leading to the metrological definition of the second through the hyperfine transition of the ground state of the cesium atom. The Josephson voltage standard directly relates electrical voltage with frequency and is used as metrological definition for the Volt.
A similar conversion between frequency and electrical current could lead to a redefinition of the Ampere, one of the 7 fundamental units of the SI, and several different systems such as e. g. single electron transistors are presently under investigation for this purpose.
A current to frequency conversion scheme based on Bloch oscillations in small Josephson junctions will be discussed. Preliminary results are in agreement with the prediction of Bloch band dynamics.