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Search Publications by: Raymond Simmonds (Fed)

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Displaying 76 - 87 of 87

Low-Leakage Superconducting Tunnel Junctions with a Single-Crystal Al2O3 Barrier

September 5, 2005
Author(s)
Seongshik Oh, Katarina Cicak, Kevin Osborn, Raymond Simmonds, David P. Pappas, Robert Mcdermott, Ken B. Cooper, Matthias Steffen, John M. Martinis
We have developed a two-step growth scheme for single-crystal Al2O3 tunnel barriers. The barriers are epitaxially grown on single-crystal rhenium (Re) base electrodes that are grown epitaxially on a sapphire substrate, while polycrystalline Al is used as

Simultaneous state measurement of coupled Josephson phase qubits

February 25, 2005
Author(s)
Robert McDermott, Raymond Simmonds, Matthias Steffen, Ken B. Cooper, Katarina Cicak, Kevin Osborn, Seongshik Oh, David P. Pappas, John M. Martinis
One of the many challenges of building a scalable quantum computer is singleshot measurement of all the quantum bits (qubits). We have used simultaneous single-shot measurement of coupled Josephson phase qubits to directly probe interaction of the qubits

Observation of Quantum Oscillations between a Josephson Phase Qubit and a Microscopic Resonator using Fast Readout

October 25, 2004
Author(s)
Ken Cooper, Matthias Steffen, Robert McDermott, Raymond Simmonds, Seongshik Oh, Dustin Hite, David P. Pappas, John M. Martinis
We have detected coherent quantum oscillations between Josephson phase qubits and microscopic critical current fluctuators by implementing a new state readout technique that is an order of magnitude faster than previous methods. The period of the

Conducting atomic force microscopy for Nanoscale tunnel barrier characterization

August 13, 2004
Author(s)
Kristine Lang, Dustin Hite, Raymond Simmonds, Robert McDermott, David P. Pappas, John M. Martinis
Increasing demands on nanometer scale properties of oxide tunnel barriers necessitate a consistent means to assess them at these lengths. Here we use conducting atomic force microscopy (CAFM) to characterize aluminum oxide (AlOx)barriers to be used in

Decoherence in Josephson Qubits from Junction Resonances

August 13, 2004
Author(s)
Raymond Simmonds, Kristine Lang, Dustin Hite, David P. Pappas, John M. Martinis
We present experimental data that demonstrates a large reduction in the coherence of a Josephson phase qubit from spurious microwave resonances. These resonances are believed to arise from resonant fluctuators in the tunnel junction that couple to the