project title: Charge pumping and ratchet effects in Josephson junction circuits
project leader: Dieter Koelle
access given (in days): 31
access used (in days): 8
local host: Jukka Pekola
home institution: University of Tubingen
country of institution: Germany
starting date (yyyy-mm-dd): 2006-03-26
The group of Tubingen (Koelle and Kleinert) have presented impressive results on ratchet effects in Josephson junction devices. These studies are of interest to LTL groups also, because ratchet effects are very analogous to pumping effects in a Josephson junction sluice, which is intensively investigated in the PICO group. The Tubingen group wants to extend their ratchet experiments down to millikelvin temperatures, and this is possible at LTL within the ULTI project.
In April 2006 professor Koelle participated in the ULTI users' meeting in Lammi, and spent a few days after that at LTL to discuss the possible common experiments on Josephson junction ratchets in the quantum regime, i.e., at mK temperatures. A plan was set to have a postdoc from Tubingen to work on this experiment at LTL. However, this person decided to take another job and, in addition, it turned out that more theoretical work is needed before a concrete experimental program can be initiated. Thus this project is still in the planning stage.