4,272 research outputs found
Single-photon-triggered quantum chaos
We demonstrate how to manipulate quantum chaos with a single photon in a
hybrid quantum device combining cavity QED and optomechanics. Specifically, we
show that this system changes between integrable and chaotic relying on the
photon-state of the injected field. This onset of chaos originates from the
photon-dependent chaotic threshold of the qubit-field coupling induced by the
optomechanical interaction. By deriving the Loschmidt Echo we observe clear
differences in the sensitivity to perturbations in the regular versus chaotic
regimes. We also present classical analog of this chaotic behavior, and find
good correspondence between chaotic quantum dynamics and classical physics. Our
work opens up a new route to achieve quantum manipulations, which are crucial
elements in engineering new types of on-chip quantum devices and quantum
information science.Comment: 11 pages, 4 figure
Controlling the Intrinsic Josephson Junction Number in a Mesa
In fabricating intrinsic Josephson
junctions in 4-terminal mesa structures, we modify the conventional fabrication
process by markedly reducing the etching rates of argon ion milling. As a
result, the junction number in a stack can be controlled quite satisfactorily
as long as we carefully adjust those factors such as the etching time and the
thickness of the evaporated layers. The error in the junction number is within
. By additional ion etching if necessary, we can controllably decrease
the junction number to a rather small value, and even a single intrinsic
Josephson junction can be produced.Comment: to bu published in Jpn. J. Appl. Phys., 43(7A) 200
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