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Displaying 26 - 50 of 104

Origin and Reduction of 1=f Magnetic Flux Noise in Superconducting Devices

October 18, 2016
Author(s)
P Kumar, David P. Pappas, Robert Mcdermott, J.W. Freeland, Clare Yu, M Beck, Hui Wang, Ruqian Wu
Magnetic flux noise is a dominant source of dephasing and energy relaxation in superconducting qubits. The noise power spectral density varies with frequency as 1=f^α, with α ≲ 1, and spans 13 orders of magnitude. Recent work indicates that the noise is

Hotspot Relaxation Dynamics in a Current Carrying Superconductor

March 17, 2016
Author(s)
Francesco Marsili, Martin Stevens, Alex Kozorezov, Varun Verma, Colin Lambert, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Matthew Shaw, Richard Mirin, Sae Woo Nam
When a photon is absorbed in a superconductor it creates a region of nonequilibrium superconductivity referred to as a hotspot [1]. The operation of most superconducting single photon detectors (microwave kinetic inductance detectors, MKIDs [2,3]

Concentric transmon qubit featuring fast tunability and an anisotropic magnetic dipole moment

January 21, 2016
Author(s)
Jochen Braumuller, Martin O. Sandberg, Michael Vissers, Andre Schneider, Steffen Schlor, Lukas Grunhaupt, Hannes Rotzinger, Michael Marthaler, Alexander Lukashenko, Amadeus Dieter, Alexey V. Ustinov, Martin Weides, David P. Pappas
We present a planar qubit design based on a superconducting circuit that we call concentric transmon. While employing a straightforward fabrication process using Al evaporation and lift-off lithography, we observe qubit lifetimes and coherence times in the

Low noise kinetic inductance traveling-wave amplifier using three-wave mixing

October 1, 2015
Author(s)
Michael R. Vissers, Robert P. Erickson, Leila R. Vale, Xian Wu, Gene C. Hilton, David P. Pappas
We have fabricated a wide-bandwidth, high dynamic range, low noise cryogenic amplifier based on a superconducting kinetic inductance traveling-wave device. The device was made from NbTiN and consisted of a long, coplanar waveguide on a silicon chip. By

Efficient Quantum State Transfer in an Engineered Chain of Quantum Bits

September 15, 2015
Author(s)
Emanuel Knill, Michael Vissers, David P. Pappas, Martin Sandberg
Here we present a method of performing quantum state transfer in a chain of superconducting quantum bits. Our protocol is based on the engineerability of the energy levels of superconducting quantum systems. This, together with the tunability of the

Quasiparticle recombination in hotspots in superconducting current-carrying nanowires

August 6, 2015
Author(s)
Alex Kozorezov, Colin Lambert, Francesco Marsili, Martin Stevens, Varun Verma, Jeffrey A. Stern, Rob Horansky, Shellee D. Dyer, Shannon Duff, David P. Pappas, Adriana Lita, Matthew D. Shaw, Richard Mirin, Sae Woo Nam
We describe a kinetic model of recombination of nonequilibrium quasiparticles generated by single photon absorption in superconducting current-carrying nanowires. The model is developed to interpret two-photon detection experiments in which a single photon

Photon-noise limited sensitivity in titanium nitride kinetic inductance detectors

February 20, 2015
Author(s)
Johannes Hubmayr, James A. Beall, Daniel T. Becker, Hsiao-Mei Cho, Gene C. Hilton, Dale Li, David P. Pappas, Jeffrey L. Van Lanen, Mark Devlin, Kent D. Irwin, Chris Groppi, Phillip Mauskopf
We demonstrate photon-noise limited performance at sub-millimeter wavelengths in microwave kinetic inductance detectors (MKIDs) made of a new superconducting material, a TiN/Ti/TiN trilayer film. Optical coupling is achieved by use of feedhorns, a standard

Frequency Comb Generation in Superconducting Resonators

October 30, 2014
Author(s)
Robert P. Erickson, Michael Vissers, Martin O. Sandberg, Steven R. Jefferts, David P. Pappas
We have generated frequency combs spanning 0.5 to 20 GHz in superconducting λ=2 resonators at T ¼ 3 K. Thin films of niobium-titanium nitride enabled this development due to their low loss, high nonlinearity, low frequency dispersion, and high critical

Superconducting nanowire single photon detectors fabricated from an amorphous Mo0.75Ge0.25 thin-film

July 15, 2014
Author(s)
Varun B. Verma, Adriana E. Lita, Michael R. Vissers, Francesco Marsili, David P. Pappas, Richard P. Mirin, Sae Woo Nam
We present the characteristics of superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous Mo0.75Ge0.25 thin -films. Fabricated devices show a saturation of the internal detection efficiency at temperatures below 1 K, with system

Dual-polarization-sensitive kinetic inductance detectors for balloon-borne, sub-millimeter polarimetry

March 20, 2014
Author(s)
James A. Beall, Dan Becker, Justus Brevik, Hsiao-Mei Cho, Gene C. Hilton, Kent D. Irwin, Dale Li, David P. Pappas, Jeffrey L. Van Lanen, Johannes Hubmayr
We are developing arrays of kinetic inductance detectors for sub-millimeter polarimetry that will be deployed on the BLAST balloon-borne instrument. The array is feedhorn-coupled, and each pixel contains two lumped-element kinetic inductance detectors

Properties of TiN for Detector and Amplifier Applications

February 8, 2014
Author(s)
Jiansong Gao, Michael R. Vissers, Martin O. Sandberg, Dale Li, Hsiao-Mei Cho, Clint Bockstiegel, Ben Mazin, Henry G. Leduc, Saptarshi Chaudhuri, David P. Pappas, K D. Irwin
We have experimentally explored and carefully characterized the important properties of TiN, including the resistivity, nonlinear kinetic inductance, the anomalous electro-dynamical response, and the two-level-system induced frequency shift and noise. We

Surface science for improved ion traps

October 1, 2013
Author(s)
David P. Pappas, Dustin A. Hite, Andrew C. Wilson, David T. Allcock, David J. Wineland, Dietrich G. Leibfried, Yves Colombe
Trapped ions are sensitive to electric-field noise from trap-electrode surfaces. This noise has been an obstacle to progress in trapped-ion quantum information processing (QIP) experiments for more than a decade. It causes motional heating of the ions, and

Micro-fabricated stylus ion trap

August 7, 2013
Author(s)
Kyle S. McKay, Christian L. Arrington, Ehren D. Baca, Jonathan J. Coleman, Yves Colombe, Patrick Finnegan, Dustin A. Hite, Andrew E. Hollowell, Robert Jordens, John D. Jost, Dietrich G. Leibfried, Adam M. Rowen, Ulrich J. Warring, David J. Wineland, David P. Pappas, Andrew C. Wilson
An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of

Optimized superconducting detectors using the proximity effect in Ti/TiN multilayers

June 14, 2013
Author(s)
David P. Pappas, Michael R. Vissers, Jiansong Gao, Martin O. Sandberg, David S. Wisbey, Kent D. Irwin
We apply the superconducting proximity effect in TiN/Ti multi-layers films to tune the critical temperature, $T_C$ (to within 10 mK) with high uniformity (less than 15 mK spread) across a 75 mm wafer. Reproducible $T_C$'s are obtained from 0.8 - 2.5 K

Radiation-suppressed superconducting quantum bit in a planar geometry

February 19, 2013
Author(s)
Martin O. Sandberg, Tomas A. Ohki, Jose A. Aumentado, Martin P. Weides, David P. Pappas
We present a superconducting transmon qubit circuit design based on large, coplanar capacitor plates and a microstrip resonator. The microstrip geometry, with the ground plane on the back, enhances access to the circuit for state preparation and

Dual-polarization sensitive MKIDs for far infrared astrophysics

December 12, 2012
Author(s)
Johannes Hubmayr, James A. Beall, Daniel T. Becker, Hsiao-Mei Cho, Brad Dober, Mark Devlin, Anna E. Fox, Dale Li, Michael D. Niemack, David P. Pappas, Leila R. Vale, Kent D. Irwin, Gene C. Hilton
We present the design for arrays of dual-polarization sensitive, superconducting sensors for far infrared astrophysics. Each pixel is feedhorn-coupled and consists of orthogonal, lumped-element kinetic inductance detectors (LEKIDs) both fabricated in the

A titanium-nitride near-infrared kinetic inductance photon-counting detector and its anomalous electrodynamics

October 1, 2012
Author(s)
Martin O. Sandberg, Fabio C. da Silva, Kent D. Irwin, David P. Pappas, Sae Woo Nam, David Wisbey, Ben Mazin, Seth Meeker, Jonas Zmuidzinas, Henry G. Leduc
We demonstrate single-photon counting at 1550 nm with titanium-nitride (TiN) microwave kinetic inductancedetectors. Full-width-at-half-maximum energy resolution of 0.4 eV is achieved. 0-, 1-, 2- photon events are resolved and shown to follow Poisson

Characterization and In-situ Monitoring of Sub-stoichiometric Adjustable TC Titanium Nitride Growth

September 21, 2012
Author(s)
Michael R. Vissers, Jiansong Gao, Jeffrey S. Kline, Martin O. Sandberg, Martin P. Weides, David S. Wisbey, David P. Pappas
The structural and electrical properties of Ti-N films deposited by reactive sputtering depend on their growth parameters, in particular the Ar:N2 gas ratio. We show that the nitrogen percentage changes the crystallographic phase of the film progressively

100-Fold Reduction of Electric-Field Noise in an Ion Trap Cleanded with In Situ Argon-Ion-Beam Bombardment

September 7, 2012
Author(s)
Dustin Hite, Yves Colombe, Andrew C. Wilson, Kenton R. Brown, Ulrich J. Warring, Robert Jordens, John D. Jost, David P. Pappas, Dietrich Leibfried, David J. Wineland, Kyle McKay
Anomalous heating of trapped atomic ions is a major obstacle to their use as quantum bits in scalable quantum computers. The physical origin of this electric field noise is not fully understood, but experimental evidence suggests that it emanates from the

Etch induced microwave losses in titanium nitride superconducting resonators

June 25, 2012
Author(s)
Martin O. Sandberg, Jeffrey S. Kline, Martin P. Weides, David S. Wisbey, David P. Pappas
We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on silicon wafers. Three different methods were investigated: fluorine- and chlorine-based reactive ion

Reduced microwave loss in trenched superconducting coplanar waveguides

February 20, 2012
Author(s)
Michael R. Vissers, Jeffrey S. Kline, Jiansong Gao, David S. Wisbey, David P. Pappas
Low loss TiN resonators were fabricated on 3" intrinsic Si substrates. By exploiting the etch rate anisotropy in a parallel plate reactive ion etch, otherwise identical coplanar waveguides with gaps of varying depth were created in the same TiN film within

Two Level System Loss in Superconducting Microwave Resonators

January 13, 2011
Author(s)
David P. Pappas, Michael R. Vissers, David S. Wisbey, Jeffrey S. Kline, Jiansong Gao
High quality factor, i.e. low loss, resonators are important for quantum information storage and addressing. In this work we study the resonance frequency and loss in superconducting coplanar waveguide resonators as a function of temperature and power. We

Low loss superconducting titanium nitride coplanar waveguide resonators

December 9, 2010
Author(s)
Michael Vissers, Jiansong Gao, David S. Wisbey, David P. Pappas, C. C. Tsuei, A. D. Corcoles, Matthias Steffen
Thin films of TiN were sputter-deposited onto Si and sapphire wafers with and without SiN buffer layers. The films were fabricated into RF coplanar waveguide resonators, and internal quality factor measurements were taken at millikelvin temperatures in