reduced flux noise
DESCRIPTION
Investigations of Quantum Coherence in Josephson Junctions and Superconducting Circuits Robert McDermott, University of Wisconsin-Madison, DMR 0805051. - PowerPoint PPT PresentationTRANSCRIPT
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SiOx-Al-SiOxSiNx-Al-SiOxSiOx-Al-SiNxSiNx-Al-SiNx
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The goal of the project is to uncover the underlying physical mechanisms that govern decoherence in superconducting quantum bits (“qubits”).
This year we have incorporated crystalline silicon nanomembranes into our qubit circuits. The excellent crystalline quality of this material leads to dramatic improvements in the quantum coherence of the device.
In other work, we have developed novel surface passivation and fabrication techniques that enable us to suppress the low-frequency magnetic noise in Superconducting QUantum Interference Devices (SQUIDs) by more than an order of magnitude. This advance has allowed us to develop the most sensitive magnetic flux sensors to date, and we expect that it will lead to additional improvements in the coherence properties of our qubit devices.
Investigations of Quantum Coherence in Josephson Junctions and Superconducting Circuits
Robert McDermott, University of Wisconsin-Madison, DMR 0805051
100
101
10210
-2
10-1
100
101
Frequency (Hz)
S (
02 /Hz)
SiOx-Al-SiOxSiNx-Al-SiOxSiOx-Al-SiNxSiNx-Al-SiNx
100
101
10210
-2
10-1
100
101
Frequency (Hz)
S (
02 /H
z)
SiOx-Al-SiOxSiNx-Al-SiOxSiOx-Al-SiNxSiNx-Al-SiNxReduced flux noise
Micrograph of SQUID circuit
Investigations of Quantum Coherence in Josephson Junctions and Superconducting Circuits
Robert McDermott, University of Wisconsin-Madison, DMR 0805051
• Supervised undergraduate researchers Antonio Puglielli, Nick Grabon, Kale Johnson, and Patrick Bollom
• Upgraded experiments in the Physics Dept. undergraduate Advanced Laboratory course. Introduced new experiment to measure violation of Bell’s inequality using polarization-entangled photons.
• Participated in UW-Madison Physics open house. Presented hands-on demonstrations of eddy-current damping, magnetic levitation with high-Tc superconductivity, and Superconducting QUantrum Interference Devices (SQUIDs)
Mie scattering apparatus, UW-Madison Physics undergraduate Advanced Laboratory