Dresden 2006 – scientific programme
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TT: Tiefe Temperaturen
TT 26: Transport - Poster Session
TT 26.23: Poster
Wednesday, March 29, 2006, 14:30–18:30, P1
Long Josephson junction filters for qubit control — •H. H. Eglmeier1, A. Kemp1, V.S. Kaplunenko2, and A. V. Ustinov1 — 1University of Erlangen-Nuremberg — 2Stanford linear accelerator, metrol magnetic measurement
Josephson junctions have been demonstrated to perform as macroscopic quantum systems with a well-controlled Hamiltonian. Most superconducting qubits require magnetic flux control for their operation. One choice is to use rapid single flux quantum (RSFQ) logic for qubit control and interfacing with room temperature electronics.
Decoherence due to 1/f noise in the RSFQ circuitry leads to the need for efficient low-frequency isolation between the control circuitry and the qubit. We present characterization measurements and simulations of a novel low-pass filter based on a long Josephson junction.
An input signal fed into the long junction is transmitted only if its frequency exceeds the plasma frequency of the junction, otherwise it is attenuated as an exponentially vanishing (evanescent) wave. For qubit control one can use low frequency signals which are only transmitted as multiples of the flux quantum. The transmission properties of the filter in the GHz range are currently investigated experimentally.