Publications (30)
Landau-Zener Transitions in an Adiabatic Quantum Computer
J. Johansson, M. H. S. Amin, A. J. Berkley +7
We report an experimental measurement of Landau-Zener transitions on an individual flux qubit within a multi-qubit superconducting chip designed for adiabatic quantum computation.…
Bolometric technique for high-resolution broadband microwave spectroscopy of ultra-low-loss samples
P. J. Turner, D. M. Broun, Saeid Kamal +7
A novel low temperature bolometric method has been devised and implemented for high-precision measurements of the microwave surface resistance of small single-crystal platelet samp…
Microwave Spectroscopy of Thermally Excited Quasiparticles in YBa_2Cu_3O_{6.99}
A. Hosseini, R. Harris, Saeid Kamal +5
We present here the microwave surface impedance of a high purity crystal of measured at 5 frequencies between 1 and 75 GHz. This data set reveals the main featu…
Hydrodynamic behaviour of Lattice Boltzmann and Lattice BGK models
O. Behrend, R. Harris, P. Warren
We present a numerical analysis of the validity of classical and generalized hydrodynamics for Lattice Boltzmann Equation (LBE) and Lattice BGK methods in two and three dimensions,…
Architectural considerations in the design of a superconducting quantum annealing processor
P. I. Bunyk, E. Hoskinson, M. W. Johnson +7
We have developed a quantum annealing processor, based on an array of tunably coupled rf-SQUID flux qubits, fabricated in a superconducting integrated circuit process [1]. Implemen…
Entanglement in a quantum annealing processor
T. Lanting, A. J. Przybysz, A. Yu. Smirnov +23
Entanglement lies at the core of quantum algorithms designed to solve problems that are intractable by classical approaches. One such algorithm, quantum annealing (QA), provides a…
Experimental Demonstration of a Robust and Scalable Flux Qubit
R. Harris, J. Johansson, A. J. Berkley +16
A novel rf-SQUID flux qubit that is robust against fabrication variations in Josephson junction critical currents and device inductance has been implemented. Measurements of the pe…
Microwave Conductivity due to Impurity Scattering in a d-wave Superconductor
A. J. Berlinsky, D. A. Bonn, R. Harris +1
The self-consistent t-matrix approximation for impurity scattering in unconventional superconductors is used to interpret recent measurements of the temperature and frequency depen…
Geometrical dependence of low frequency noise in superconducting flux qubits
T. Lanting, A. J. Berkley, B. Bumble +11
A general method for directly measuring the low-frequency flux noise (below 10 Hz) in compound Josephson junction superconducting flux qubits has been used to study a series of 85…
Tunneling spectroscopy using a probe qubit
A. J. Berkley, A. J. Przybysz, T. Lanting +15
We describe a quantum tunneling spectroscopy technique that requires only low bandwidth control. The method involves coupling a probe qubit to the system under study to create a lo…
Implementation of a Quantum Annealing Algorithm Using a Superconducting Circuit
R. Harris, A. J. Berkley, J. Johansson +10
A circuit consisting of a network of coupled compound Josephson junction rf-SQUID flux qubits has been used to implement an adiabatic quantum optimization algorithm. It is shown th…
Phenomenology of a-axis and b-axis charge dynamics from microwave spectroscopy of highly ordered YBa2Cu3O6.50 and YBa2Cu3O6.993
R. Harris, P. J. Turner, Saeid Kamal +9
Extensive measurements of the microwave conductivity of highly pure and oxygen-ordered \YBCO single crystals have been performed as a means of exploring the intrinsic charge dynami…
Experimental Investigation of an Eight Qubit Unit Cell in a Superconducting Optimization Processor
R. Harris, M. W. Johnson, T. Lanting +23
A superconducting chip containing a regular array of flux qubits, tunable interqubit inductive couplers, an XY-addressable readout system, on-chip programmable magnetic memory, and…
Probing High Frequency Noise with Macroscopic Resonant Tunneling
T. Lanting, M. H. S. Amin, M. W. Johnson +9
We have developed a method for extracting the high-frequency noise spectral density of an rf-SQUID flux qubit from macroscopic resonant tunneling (MRT) rate measurements. The extra…
A scalable control system for a superconducting adiabatic quantum optimization processor
M. W. Johnson, P. Bunyk, F. Maibaum +10
We have designed, fabricated and operated a scalable system for applying independently programmable time-independent, and limited time-dependent flux biases to control superconduct…
A scalable readout system for a superconducting adiabatic quantum optimization system
A. J. Berkley, M. W. Johnson, P. Bunyk +7
We have designed, fabricated and tested an XY-addressable readout system that is specifically tailored for the reading of superconducting flux qubits in an integrated circuit that…
Probing Noise in Flux Qubits via Macroscopic Resonant Tunneling
R. Harris, M. W. Johnson, S. Han +13
Macroscopic resonant tunneling between the two lowest lying states of a bistable RF-SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate a…
A frequency and sensitivity tunable microresonator array for high-speed quantum processor readout
J. D. Whittaker, L. J. Swenson, M. H. Volkmann +18
Superconducting microresonators have been successfully utilized as detection elements for a wide variety of applications. With multiplexing factors exceeding 1,000 detectors per tr…
Observation of Co-tunneling in Pairs of Coupled Flux Qubits
T. Lanting, R. Harris, J. Johansson +17
We report measurements of macroscopic resonant tunneling between the two lowest energy states of a pair of magnetically coupled rf-SQUID flux qubits. This technique provides a dire…
Demonstration of nonstoquastic Hamiltonian in coupled superconducting flux qubits
I. Ozfidan, C. Deng, A. Y. Smirnov +45
Quantum annealing (QA) is a heuristic algorithm for finding low-energy configurations of a system, with applications in optimization, machine learning, and quantum simulation. Up t…
Observation of Weak-Limit Quasiparticle Scattering via Broadband Microwave Spectroscopy of a d-Wave Superconductor
P. J. Turner, R. Harris, Saeid Kamal +10
There has long been a discrepancy between microwave conductivity measurements in high temperature superconductors and the conductivity spectrum expected in the simplest models for…
Oxygen Chain Disorder as the Weak Scattering Source in YBaCuO
J. S. Bobowski, P. J. Turner, R. Harris +3
The microwave conductivity of an ultra-pure single crystal of YBaCuO has been measured deep in the superconducting state as a continuous function of frequency from…
Measuring and Suppressing Error Correlations in Quantum Circuits
C. L. Edmunds, C. Hempel, R. Harris +4
Quantum error correction provides a path to large-scale quantum computers, but is built on challenging assumptions about the characteristics of the underlying errors. In particular…
Sign- and magnitude-tunable coupler for superconducting flux qubits
R. Harris, A. J. Berkley, M. W. Johnson +11
We experimentally confirm the functionality of a coupling element for flux-based superconducting qubits, with a coupling strength whose sign and magnitude can be tuned {\it in…
Astrophotonics: astronomy and modern optics
S. Minardi, R. Harris, L. Labadie
Much of the progress in Astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs. In this review we describe the field of astrop…
Synchronization of Multiple Coupled rf-SQUID Flux Qubits
R. Harris, F. Brito, A. J. Berkley +10
A practical strategy for synchronizing the properties of compound Josephson junction rf-SQUID qubits on a multiqubit chip has been demonstrated. The impacts of small () fab…
Generalized Thermal Lattice Gases
O. Baran, C. C. Wan, R. Harris
We show how to employ thermal lattice gas models to describe non-equilibrium phenomena. This is achieved by relaxing the restrictions of the usual micro-canonical ensemble for thes…
A Compound Josephson Junction Coupler for Flux Qubits With Minimal Crosstalk
R. Harris, T. Lanting, A. J. Berkley +7
An improved tunable coupling element for building networks of coupled rf-SQUID flux qubits has been experimentally demonstrated. This new form of coupler, based upon the compound J…
Absolute values of the London penetration depth in YBa2Cu3O6+y measured by zero field ESR spectroscopy on Gd doped single crystals
T. Pereg-Barnea, P. J. Turner, R. Harris +6
Zero-field electron spin resonance (ESR) of dilute Gd ions substituted for Y in the cuprate superconductor YBaCuO is used as a novel technique for measuring the…
Performance of the First 150 mm Diameter Cryogenic Silicon Ionization Detectors with Contact-Free Electrodes
N. Mast, A. Kennedy, H. Chagani +9
Cryogenic semiconductor detectors operated at temperatures below 100 mK are commonly used in particle physics experiments searching for dark matter. The largest such germanium and…