Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 8: Transport: Quantum Coherence and Quantum Information Systems 1 (jointly with TT, MA)
HL 8.1: Vortrag
Montag, 26. März 2012, 09:30–09:45, BH 243
Coherence in a transmon qubit with epitaxial tunnel junctions — •Martin Weides1,4, Jeffrey Kline1, Michael Vissers1, Martin Sandberg1, David Wisbey1,2, Blake Johnson3, Thomas Ohki3, and David Pappas1 — 1National Institute of Standards and Technology, Boulder, Colorado 80305, USA — 2Saint Louis University, St. Louis, Missouri 63103, USA — 3Raytheon BBN Technologies, Cambridge, Massachusetts 02138, USA — 4Karlsruhe Institute of Technology, Germany
Transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors were developed. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T1 is .72−.86 µ sec and the ensemble dephasing time T2* is slightly larger than T1. The dephasing time T2 (1.36 µ sec) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit’s inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements.