5,324 research outputs found
Spin correlated interferometry for polarized and unpolarized photons on a beam splitter
Spin interferometry of the 4th order for independent polarized as well as
unpolarized photons arriving simultaneously at a beam splitter and exhibiting
spin correlation while leaving it, is formulated and discussed in the quantum
approach. Beam splitter is recognized as a source of genuine singlet photon
states. Also, typical nonclassical beating between photons taking part in the
interference of the 4th order is given a polarization dependent explanation.Comment: RevTeX, 19 pages, 1 ps figure, author web page at
http://m3k.grad.hr/pavici
Nano-electromechanical switchable photonic metamaterials
We introduce mechanically reconfigurable electrostatically-driven photonic metamaterials (RPMs) as a generic platform for large-range tuning and switching of photonic metamaterial properties. Here we illustrate this concept with a high-contrast metamaterial electro-optic switch exhibiting relative reflection changes of up to 72% in the optical part of the spectrum
Generation of frequency multiplexed entangled single photons assisted by the entanglement
We present a scheme to generate the frequency multiplexed entangled (FME)
single photons based on the entanglement between two species atomic mixture
ensemble. The write and reads fields driven according to a certain timing
sequence, the generation of FME single photons can be repeated until success is
achieved. The source might have significant applications in wavelength division
multiplexing quantum key distribution.Comment: 4 pages, 4 figures, submitted to PR
Mode-Locked Two-Photon States
The concept of mode locking in laser is applied to a two-photon state with
frequency entanglement. Cavity enhanced parametric down-conversion is found to
produce exactly such a state. The mode-locked two-photon state exhibits a
comb-like correlation function. An unbalanced Hong-Ou-Mandel type
interferometer is used to measure the correlation function. A revival of the
typical interference dip is observed. We will discuss schemes for engineering
of quantum states in time domain.Comment: 4 pages, 5 figure
Discovering Debtor Patterns of Centrelink Customers
Data mining is currently becoming an increasingly hot research field, but a large gap still remains between the research of data mining and its application in real-world business. As one of the largest data users in Australia, Centrelink has huge volume of data in data warehouse and tapes. Based on the available data, Centrelink is seeking to find underlying patterns to be able to intervene earlier to prevent or minimize debt. To discover the debtor patterns of Centrelink customers and bridge the gap between data mining research and application, we have done a project on improving income reporting to discover the patterns of those customers who were or are in debt to Centrelink. Two data models were built respectively for demographic data and activity data, and decision tree and sequence mining were used respectively to discover demographic patterns and activity sequence patterns of debtors. The project produced some potentially interesting results, and paved the way for more data mining applications in Centrelink in near future. © 2006, Australian Computer Society, Inc
Security improvement of using modified coherent state for quantum cryptography
Weak coherent states as a photon source for quantum cryptography have limit
in secure data rate and transmission distance because of the presence of
multi-photon events and loss in transmission line. Two-photon events in a
coherent state can be taken out by a two-photon interference scheme. We
investigate the security issue of utilizing this modified coherent state in
quantum cryptography. A 4 dB improvement in secure data rate or a nearly
two-fold increase in transmission distance over the coherent state are found.
With a recently proposed and improved encoding strategy, further improvement is
possible.Comment: 5 pages, 2 figures, to appear in Physical Review
Demonstration of Controllable Temporal Distinguishability in a Three-Photon State
Multi-photon interference is at the heart of the recently proposed linear
optical quantum computing scheme and plays an essential role in many protocols
in quantum information. Indistinguishability is what leads to the effect of
quantum interference. Optical interferometers such as Michaelson interferometer
provide a measure for second-order coherence at one-photon level and
Hong-Ou-Mandel interferometer was widely employed to describe two-photon
entanglement and indistinguishability. However, there is not an effective way
for a system of more than two photons. Recently, a new interferometric scheme
was proposed to quantify the degree of multi-photon distinguishability. Here we
report an experiment to implement the scheme for three-photon case. We are able
to generate three photons with different degrees of temporal distinguishability
and demonstrate how to characterize them by the visibility of three-photon
interference. This method of quantitative description of multi-photon
indistinguishability will have practical implications in the implementation of
quantum information protocols
- …