475 research outputs found
Experimental Demonstration of a Quantum Circuit using Linear Optics Gates
One of the main advantages of an optical approach to quantum computing is the
fact that optical fibers can be used to connect the logic and memory devices to
form useful circuits, in analogy with the wires of a conventional computer.
Here we describe an experimental demonstration of a simple quantum circuit of
that kind in which two probabilistic exclusive-OR (XOR) logic gates were
combined to calculate the parity of three input qubits.Comment: v2 is final PRA versio
Single Photons on Pseudo-Demand from Stored Parametric Down-Conversion
We describe the results of a parametric down-conversion experiment in which
the detection of one photon of a pair causes the other photon to be switched
into a storage loop. The stored photon can then be switched out of the loop at
a later time chosen by the user, providing a single photon for potential use in
a variety of quantum information processing applications. Although the stored
single photon is only available at periodic time intervals, those times can be
chosen to match the cycle time of a quantum computer by using pulsed
down-conversion. The potential use of the storage loop as a photonic quantum
memory device is also discussed.Comment: 8 pages, 7 Figs., RevTe
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Hay Quality Sensory Evaluation Form – Mixed Cereal/Pea or Vetc
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Hay Quality Sensory Evaluation Form – Timothy; Export & Hors
All-Optical Switching Using the Quantum Zeno Effect and Two-Photon Absorption
We have previously shown that the quantum Zeno effect can be used to
implement quantum logic gates for quantum computing applications, where the
Zeno effect was produced using a strong two-photon absorbing medium. Here we
show that the Zeno effect can also be used to implement classical logic gates
whose inputs and outputs are high-intensity fields (coherent states). The
operation of the devices can be understood using a quasi-static analysis, and
their switching times are calculated using a dynamic approach. The two-photon
absorption coefficient of rubidium vapor is shown to allow operation of these
devices at relatively low power levels.Comment: 21 pages, 11 figures. Submitted to Phys. Rev.
Investigation of a single-photon source based on quantum interference
We report on an experimental investigation of a single-photon source based on
a quantum interference effect first demonstrated by Koashi, Matsuoka, and
Hirano [Phys. Rev. A 53, 3621 (1996)]. For certain types of measurement-based
quantum information processing applications this technique may be useful as a
high rate, but random, source of single photons.Comment: Submitted to the New J. Phys. Focus Issue on "Measurement-based
quantum information processing
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