Urgent replacement of dilution refrigerators primary pumps

点击翻译按钮获取中文摘要

We are requesting an equipment grant to replace the current pumping system of our dilution refrigerators with newly designed dry pumps sold by Alcatel. This urgent replacement is absolutely needed for Gervais team to continue their research on the 5/2 fractional quantum Hall state, which is by far the most promising candidate for a proof-of-concept of the non-abelian anyons. This study is carried out in the very best semiconductor heterostructure available, grown at Lucent Technologies (Dr. Loren Pfeiffer, now at Princeton). In 2008, we have shown, in collaboration with Das Sarma, that the intrinsic structure of the 5/2-state, or gap, cannot be accounted for by current state-of-the-art numerical studies. We are now in the process to extract the spin polarization of the 5/2 FQH state, a measurement which, in conjunction with the e*=e/4 charge measurement of the fractional charge by the Weizmann and Harvard group, could nail down the non-abelian nature of the 5/2 state. For us to succeed, urgent assistance is needed from NSERC for the replacement of our dilution refrigerator main pumps which have been so problematic that we were unable to obtain new data on the 5/2 state this year.