2,881 research outputs found
Two New Genera of Hemisarcoptidae (Acari: Astigmata) From the Huron Mountains of Northern Michigan
Two new genera and species of Hemisarcoptidae, Superioropus huronmontanus and Huronopus michiganensis are described from deutonymphs phoretic on ichneumonid wasps from the Huron Mountains, Marquette County, Michigan
A superconducting qubit with Purcell protection and tunable coupling
We present a superconducting qubit for the circuit quantum electrodynamics
architecture that has a tunable coupling strength g. We show that this coupling
strength can be tuned from zero to values that are comparable with other
superconducting qubits. At g = 0 the qubit is in a decoherence free subspace
with respect to spontaneous emission induced by the Purcell effect. Furthermore
we show that in the decoherence free subspace the state of the qubit can still
be measured by either a dispersive shift on the resonance frequency of the
resonator or by a cycling-type measurement.Comment: 4 pages, 3 figure
Geometric efficiency of an electroformed nickel solar concentrator
Geometric efficiency of electroformed paraboloidal nickel solar energy concentrator calculated from optical ray trace dat
Simulation study of intracity helicopter operations under instrument conditions to category 1 minimums
A fixed-base simulator study was conducted to define pilot workload and task performance associated with instrument flight operations for an intracity helicopter passenger service. Displays considered necessary to provide a minimal capability under Instrument Flight Rules conditions were used to fly a representative commercial helicopter route structure in the New York area, with each terminal assumed to be equipped with a precision approach guidance system. A cross section of pilots participated as test subjects, and despite the high workload level, the results indicated that for the assumptions employed, minimums of 61 m (200 ft) ceiling and 805 m (0.5 mile) visibility were feasible
Interacting Qubit-Photon Bound States with Superconducting Circuits
Qubits strongly coupled to a photonic crystal give rise to many exotic
physical scenarios, beginning with single and multi-excitation qubit-photon
dressed bound states comprising induced spatially localized photonic modes,
centered around the qubits, and the qubits themselves. The localization of
these states changes with qubit detuning from the band-edge, offering an avenue
of in situ control of bound state interaction. Here, we present experimental
results from a device with two qubits coupled to a superconducting microwave
photonic crystal and realize tunable on-site and inter-bound state
interactions. We observe a fourth-order two photon virtual process between
bound states indicating strong coupling between the photonic crystal and
qubits. Due to their localization-dependent interaction, these states offer the
ability to create one-dimensional chains of bound states with tunable and
potentially long-range interactions that preserve the qubits' spatial
organization, a key criterion for realization of certain quantum many-body
models. The widely tunable, strong and robust interactions demonstrated with
this system are promising benchmarks towards realizing larger, more complex
systems of bound states
Observation of a dissipative phase transition in a one-dimensional circuit QED lattice
Condensed matter physics has been driven forward by significant experimental
and theoretical progress in the study and understanding of equilibrium phase
transitions based on symmetry and topology. However, nonequilibrium phase
transitions have remained a challenge, in part due to their complexity in
theoretical descriptions and the additional experimental difficulties in
systematically controlling systems out of equilibrium. Here, we study a
one-dimensional chain of 72 microwave cavities, each coupled to a
superconducting qubit, and coherently drive the system into a nonequilibrium
steady state. We find experimental evidence for a dissipative phase transition
in the system in which the steady state changes dramatically as the mean photon
number is increased. Near the boundary between the two observed phases, the
system demonstrates bistability, with characteristic switching times as long as
60 ms -- far longer than any of the intrinsic rates known for the system. This
experiment demonstrates the power of circuit QED systems for studying
nonequilibrium condensed matter physics and paves the way for future
experiments exploring nonequilbrium physics with many-body quantum optics
Tunable coupling in circuit quantum electrodynamics with a superconducting V-system
Recent progress in superconducting qubits has demonstrated the potential of
these devices for the future of quantum information processing. One desirable
feature for quantum computing is independent control of qubit interactions as
well as qubit energies. We demonstrate a new type of superconducting charge
qubit that has a V-shaped energy spectrum and uses quantum interference to
provide independent control over the qubit energy and dipole coupling to a
superconducting cavity. We demonstrate dynamic access to the strong coupling
regime by tuning the coupling strength from less than 200 kHz to more than 40
MHz. This tunable coupling can be used to protect the qubit from cavity-induced
relaxation and avoid unwanted qubit-qubit interactions in a multi-qubit system.Comment: 5 pages, 4 figure
Beyond XSPEC: Towards Highly Configurable Analysis
We present a quantitative comparison between software features of the defacto
standard X-ray spectral analysis tool, XSPEC, and ISIS, the Interactive
Spectral Interpretation System. Our emphasis is on customized analysis, with
ISIS offered as a strong example of configurable software. While noting that
XSPEC has been of immense value to astronomers, and that its scientific core is
moderately extensible--most commonly via the inclusion of user contributed
"local models"--we identify a series of limitations with its use beyond
conventional spectral modeling. We argue that from the viewpoint of the
astronomical user, the XSPEC internal structure presents a Black Box Problem,
with many of its important features hidden from the top-level interface, thus
discouraging user customization. Drawing from examples in custom modeling,
numerical analysis, parallel computation, visualization, data management, and
automated code generation, we show how a numerically scriptable, modular, and
extensible analysis platform such as ISIS facilitates many forms of advanced
astrophysical inquiry.Comment: Accepted by PASP, for July 2008 (15 pages
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