542 research outputs found
Philippine Ethnography: A Critically Annotated and Selected Bibliography
This volume is a comprehensive listing of reference sources for Philippine ethnology, excluding physical anthropology and de-emphasizing folklore and linguistics. It is published as part of the East-West Bibliographic Series. This listing includes books, journal articles, mimeographed papers, and official publications selected on the basis of the ratings of sixty-two Philippine specialists. Several titles were added to fill the need for material in certain areas
Coherent Operation of a Gap-tunable Flux Qubit
We replace the Josephson junction defining a three-junction flux qubit's
properties with a tunable direct current superconducting quantum interference
devices (DC-SQUID) in order to tune the qubit gap during the experiment. We
observe different gaps as a function of the external magnetic pre-biasing field
and the local magnetic field through the DC-SQUID controlled by high-bandwidth
on chip control lines. The persistent current and gap behavior correspond to
numerical simulation results. We set the sensitivity of the gap on the control
lines during the sample design stage. With a tuning range of several GHz on a
qubit dynamics timescale, we observe coherent system dynamics at the degeneracy
point.Comment: 3 pages, 4 figure
A superconducting qubit as a quantum transformer routing entanglement between a microscopic quantum memory and a macroscopic resonator
We demonstrate experimentally the creation and measurement of an entangled
state between a microscopic two level system and a macroscopic superconducting
resonator where their indirect interaction is mediated by an artificial atom, a
superconducting persistent current qubit (PCQB). We show that the microscopic
two level system, formed by a defect in an oxide layer, exhibits an order of
magnitude longer dephasing time than the PCQB, while the dephasing time of the
entangled states between the microscopic two level system and macroscopic
superconducting resonator is significantly longer than the dephasing time in
the persistent current qubits. This demonstrates the possibility that a qubit
of moderate coherence properties can be used in practice to address low
decoherence quantum memories by connecting them to macroscopic circuit QED
quantum buses, leading future important implications for quantum information
processing tasks.Comment: 4 figure
Quantum metrology beyond the classical limit under the effect of dephasing
Quantum sensors have the potential to outperform their classical
counterparts. For classical sensing, the uncertainty of the estimation of the
target fields scales inversely with the square root of the measurement time T.
On the other hand, by using quantum resources, we can reduce this scaling of
the uncertainty with time to 1/T. However, as quantum states are susceptible to
dephasing, it has not been clear whether we can achieve sensitivities with a
scaling of 1/T for a measurement time longer than the coherence time. Here, we
propose a scheme that estimates the amplitude of globally applied fields with
the uncertainty of 1/T for an arbitrary time scale under the effect of
dephasing. We use one-way quantum computing based teleportation between qubits
to prevent any increase in the correlation between the quantum state and its
local environment from building up and have shown that such a teleportation
protocol can suppress the local dephasing while the information from the target
fields keeps growing. Our method has the potential to realize a quantum sensor
with a sensitivity far beyond that of any classical sensor
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