March 2012
Abstracts of the QSIT Lunch Seminar, March 1, 2012
Integration of quantum dots with microwave circuits
by Tobias Frey*, Quantum Device Lab and Nanophysics Group, ETH Zurich
Research on semiconductor quantum dots has contributed to the understanding of the physics of individual charges and spins in a solid-state environment. Typically, quantum dots are investigated by direct current (dc) transport measurements or using quantum point contacts for charge sensing. Instead we have realized a novel device in which a semiconductor double quantum dot is coupled to a high quality transmission line resonator. This approach allows us to study the interaction between electronic states and GHz-frequency photons in great detail. In a first experiment we characterize the properties of the double dot by measuring both its dispersive and dissipative interaction with the resonator.
T. Frey, P.J. Leek, M. Beck, A. Blais, T. Ihn, K. Ensslin, and A. Wallraff, PRL 108, 046807 (2012)
*Co-auhors: P. J. Leek1, M. Beck2, A. Blais3, T. Ihn2, K. Ensslin2, A. Wallraff2
1 University of Oxford, U.K.
2 ETH Zurich
3 l'Université de Sherbrooke (Québec), Canada
Cryogenic voltage switches for ultra-fast ion-trap applications
by Joseba Alonso Otamendi, Trapped Ion Quantum Information Group, ETH Zurich
Cryogenic ultra-fast switches (switching time below 10 ns) open the door to a new operating regime with potential applications for ion-trap quantum-information experiments. Transport routines faster than an ion's single secular oscillation, as well as motional-state squeezing and enhanced entanglement are prominent applications which can make use of fast switching of the voltages on the trap electrodes. We have tested different candidate switches at liquid-nitrogen (77 K) and liquid-helium temperature (4.2 K). The CMOS integrated circuit HC4066 from Texas Instruments proved to be the fastest (below 4 ns) and will be integrated into an ion-trap setup which is currently being finalized.