7,779 research outputs found
Projection Measurement of the Maximally Entangled N-Photon State for a Demonstration of N-Photon de Broglie Wavelength
We construct a projection measurement process for the maximally entangled
N-photon state (the NOON-state) with only linear optical elements and
photodetectors. This measurement process will give null result for any N-photon
state that is orthogonal to the NOON state. We examine the projection process
in more detail for N=4 by applying it to a four-photon state from type-II
parametric down-conversion. This demonstrates an orthogonal projection
measurement with a null result. This null result corresponds to a dip in a
generalized Hong-Ou-Mandel interferometer for four photons. We find that the
depth of the dip in this arrangement can be used to distinguish a genuine
entangled four-photon state from two separate pairs of photons. We next apply
the NOON state projection measurement to a four-photon superposition state from
two perpendicularly oriented type-I parametric down-conversion processes. A
successful NOON state projection is demonstrated with the appearance of the
four-photon de Broglie wavelength in the interference fringe pattern.Comment: 8 pages, 3 figures, new title, some content change, replaced Fig.
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
On classical string configurations
Equations which define classical configurations of strings in are
presented in a simple form. General properties as well as particular classes of
solutions of these equations are considered.Comment: 10 pages, Latex, no figures, trivial corrections, submitted to Modern
Physics Letters
Learning preferences for large scale multi-label problems
Despite that the majority of machine learning approaches aim to solve binary classification problems, several real-world applications require specialized algorithms able to handle many different classes, as in the case of single-label multi-class and multi-label classification problems. The Label Ranking framework is a generalization of the above mentioned settings, which aims to map instances from the input space to a total order over the set of possible labels. However, generally these algorithms are more complex than binary ones, and their application on large-scale datasets could be untractable. The main contribution of this work is the proposal of a novel general online preference-based label ranking framework. The proposed framework is able to solve binary, multi-class, multi-label and ranking problems. A comparison with other baselines has been performed, showing effectiveness and efficiency in a real-world large-scale multi-label task
Quantum correlations of twophoton polarization states in the parametric down-conversion process
We consider correlation properties of twophoton polarization states in the
parametric down-conversion process. In our description of polarization states
we take into account the simultaneous presence of colored and white noise in
the density matrix. Within the considered model we study the dependence of the
von Neumann entropy on the noise amount in the system and derive the
separability condition for the density matrix of twophoton polarization state,
using Perec-Horodecki criterion and majorization criterion. Then the dependence
of the Bell operator (in CHSH form) on noise is studied. As a result, we give a
condition for determining the presence of quantum correlation states in
experimental measurements of the Bell operator. Finally, we compare our
calculations with experimental data [doi:10.1103/PhysRevA.73.062110] and give a
noise amount estimation in the photon polarization state considered there.Comment: 10 pages, 7 figures; corrected typo
Possible effects of tilt order on phase transitions of a fixed connectivity surface model
We study the phase structure of a phantom tethered surface model shedding
light on the internal degrees of freedom (IDOF), which correspond to the
three-dimensional rod like structure of the lipid molecules. The so-called tilt
order is assumed as IDOF on the surface model. The model is defined by
combining the conventional spherical surface model and the XY model, which
describes not only the interaction between lipids but also the interaction
between the lipids and the surface. The interaction strength between IDOF and
the surface varies depending on the interaction strength between the variables
of IDOF. We know that the model without IDOF undergoes a first-order transition
of surface fluctuations and a first-order collapsing transition. We observe in
this paper that the order of the surface fluctuation transition changes from
first-order to second-order and to higher-order with increasing strength of the
interaction between IDOF variables. On the contrary, the order of collapsing
transition remains first-order and is not influenced by the presence of IDOF.Comment: 20 pages, 14 figure
Plasmonic amplifier of the evanescent field of free electrons
We show experimentally for the first time that free electron evanescent fields can be amplified by a plasmonic nanolayer in much that same way as optical evanescent fields are amplified in the poor-man's super-lens
Demonstration of Temporal Distinguishability in a Four-Photon State and a Six-Photon State
An experiment is performed to demonstrate the temporal distinguishability of
a four-photon state and a six-photon state, both from parametric
down-conversion. The experiment is based on a multi-photon interference scheme
in a recent discovered NOON-state projection measurement. By measuring the
visibility of the interference dip, we can distinguish the various scenarios in
the temporal distribution of the pairs and thus quantitatively determine the
degree of temporal (in)distinguishability of a multi-photon state
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