project title: Investigation of Higher Order Moments of Noise Using Coulomb Blockaded Josephson Junction
project leader: Dr. Julien Delahaye
access given (in days): 31
access used (in days): 14
local host: Prof. Pertti Hakonen
home institution: LEPES-CNRS, Grenoble, France
country of institution: France
starting date (yyyy-mm-dd): 2005-02-05
The objective of this ULTI project is to measure higher moment of shot noise with a Coulomb blockaded Josepshon nano-junction. The effect of shot noise on such detector was previously measured by the nanogroup of the Low Temperature Laboratory (see previous ULTI project). In 2004, a close circuit was theoretically proposed in order to detect non-gaussian noise fluctuations.
We have employed a Coulomb blockaded Josephson junction (CBJJ) to measure noise generated by a superconducting SET which was capacitively connected to the detector. We find a strong modification of the IV curve of the CBJJ under the influence of the noise. The voltage dependence of the current changes in the detector can be employed to deduce the frequency dependence of the noise from the SET. A manuscript on the results is under preparation. Recently, we have extended this experimental work towards understanding of the duality of IV curves across the superconductor-insulator transition, which is a very thoroughly studied problem in theory without any clear experimental verification.