5,967 research outputs found
Concurrence for multipartite states
We construct a generalized concurrence for general multipartite states based
on local W-class and GHZ-class operators. We explicitly construct the
corresponding concurrence for three-partite states. The construction of the
concurrence is interesting since it is based on local operators.Comment: 5 page
A class of quantum gate entangler
We construct quantum gate entanglers for different classes of multipartite
states based on definition of W and GHZ concurrence classes. First, we review
the basic construction of concurrence classes based on orthogonal complement of
a positive operator valued measure (POVM) on quantum phase. Then, we construct
quantum gates entanglers for different classes of multi-qubit states. In
particular, we show that these operators can entangle multipartite state if
they satisfy some conditions for W and GHZ classes of states. Finally, we
explicitly give the W class and GHZ classes of quantum gate entanglers for
four-qubit states.Comment: 5 pages, accepted for publication in Physica Scripta for the
CEWQO2009 proceedings
Low-excitation blobs in the Magellanic Clouds
Aims : We study an unknown, or very poorly known, interstellar HII component
in the Magellanic Clouds. This is the first study ever devoted to this class of
objects, which we call Low-excitation blobs (LEBs).
Methods : We used low-dispersion spectroscopy carried out at ESO to obtain
emission line intensities of Ha, Hb, and [OIII] (4959+5007) for 15 objects in
the Large Magellanic Cloud and 14 objects in the Small Magellanic Cloud.
Results are displayed in excitation ([oiii]/Hb ratio) versus Hb luminosity
diagrams.
Results : We show the presence of an LEB component in the Magellanic Clouds
and study its relationship with the already known class of high-excitation
blobs (HEBs). The newly found LEBs are lower excitation counterparts of HEBs
and are powered by less massive exciting stars. Further study of LEBs is
expected to provide new pieces of information for a better understanding the
low mass end of the upper initial mass function in the Magellanic Clouds.Comment: Accepted in A&
General pure multipartite entangled states and the Segre variety
In this paper, we construct a measure of entanglement by generalizing the
quadric polynomial of the Segre variety for general multipartite states. We
give explicit expressions for general pure three-partite and four-partite
states. Moreover, we will discuss and compare this measure of entanglement with
the generalized concurrence.Comment: 5 page
Noncommutative geometrical structures of entangled quantum states
We study the noncommutative geometrical structures of quantum entangled
states. We show that the space of a pure entangled state is a noncommutative
space. In particular we show that by rewritten the conifold or the Segre
variety we can get a -deformed relation in noncommutative geometry. We
generalized our construction into a multi-qubit state. We also in detail
discuss the noncommutative geometrical structure of a three-qubit state.Comment: 7 page
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