1,050 research outputs found
Multisetting Bell-type inequalities for detecting genuine tripartite entanglement
In a recent paper, Bancal et al. put forward the concept of
device-independent witnesses of genuine multipartite entanglement. These
witnesses are capable of verifying genuine multipartite entanglement produced
in a lab without resorting to any knowledge of the dimension of the state space
or of the specific form of the measurement operators. As a by-product they
found a three-party three-setting Bell inequality which enables to detect
genuine tripartite entanglement in a noisy 3-qubit Greenberger-Horne-Zeilinger
(GHZ) state for visibilities as low as 2/3 in a device-independent way. In this
paper, we generalize this inequality to an arbitrary number of settings,
demonstrating a threshold visibility of 2/pi~0.6366 for number of settings
going to infinity. We also present a pseudo-telepathy Bell inequality achieving
the same threshold value. We argue that our device-independent witnesses are
optimal in the sense that the above value cannot be beaten with
three-party-correlation Bell inequalities.Comment: 7 page
Maximal violation of the I3322 inequality using infinite dimensional quantum systems
The I3322 inequality is the simplest bipartite two-outcome Bell inequality
beyond the Clauser-Horne-Shimony-Holt (CHSH) inequality, consisting of three
two-outcome measurements per party. In case of the CHSH inequality the maximal
quantum violation can already be attained with local two-dimensional quantum
systems, however, there is no such evidence for the I3322 inequality. In this
paper a family of measurement operators and states is given which enables us to
attain the largest possible quantum value in an infinite dimensional Hilbert
space. Further, it is conjectured that our construction is optimal in the sense
that measuring finite dimensional quantum systems is not enough to achieve the
true quantum maximum. We also describe an efficient iterative algorithm for
computing quantum maximum of an arbitrary two-outcome Bell inequality in any
given Hilbert space dimension. This algorithm played a key role to obtain our
results for the I3322 inequality, and we also applied it to improve on our
previous results concerning the maximum quantum violation of several bipartite
two-outcome Bell inequalities with up to five settings per party.Comment: 9 pages, 3 figures, 1 tabl
The generalized identification of truly interfacial molecules (ITIM) algorithm for nonplanar interfaces
We present a generalized version of the ITIM algorithm for the identification of interfacial molecules, which is able to treat arbitrarily shaped interfaces. The algorithm exploits the similarities between the concept of probe sphere used in ITIM and the circumsphere criterion used in the α-shapes approach, and can be regarded either as a reference-frame independent version of the former, or as an extended version of the latter that includes the atomic excluded volume. The new algorithm is applied to compute the intrinsic orientational order parameters of water around a dodecylphosphocholine and a cholic acid micelle in aqueous environment, and to the identification of solvent-reachable sites in four model structures for soot. The additional algorithm introduced for the calculation of intrinsic density profiles in arbitrary geometries proved to be extremely useful also for planar interfaces, as it allows to solve the paradox of smeared intrinsic profiles far from the interface. © 2013 American Institute of Physics
The randomly driven Ising ferromagnet, Part II: One and two dimensions
We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics
under the influence of a fast switching, random external field. In Part I, we
introduced a general formalism for describing such systems and presented the
mean field theory. In this article we derive results for the one dimensional
case, which can be only partially solved. Monte Carlo simulations performed on
a square lattice indicate that the main features of the mean field theory
survive the presence of strong fluctuations.Comment: 10 pages in REVTeX/LaTeX format, 17 eps/ps figures. Submitted to
Journal of Physics
Transport on randomly evolving trees
The time process of transport on randomly evolving trees is investigated. By
introducing the notions of living and dead nodes a model of random tree
evolution is constructed which describes the spreading in time of objects
corresponding to nodes. By using the method of the age-dependent branching
processes we derive the joint distribution function of the number of living and
dead nodes, and determine the correlation between these node numbers as a
function of time. Also analyzed are the stochastic properties of the end-nodes;
and the correlation between the numbers of living and dead end-nodes is shown
to change its character suddenly at the very beginning of the evolution
process. The survival probability of random trees is investigated and
expressions are derived for this probability.Comment: 16 pages, 8 figures, published in Phys. Rev. E 72, 051101 (2005
Hársméz diasztázaktivitásának változása hőkezelés hatására, illetve a tárolás során = Changes in the diastase activity of linden honey due to heat treatment, and during storage
Narancs és narancslevek C-vitamin tartalmának összehasonlító vizsgálata = Comparative study of the vitamin-C content of orange and orange-juices
A citrusfélék közül Magyarországon a narancsot fogyasztják a leginkább. A feldolgozás során azonban a kiindulási gyümölcs beltartalmi paraméterei megváltoznak, s a C-vitamin tartalom is csökken. A gyümölcs hűtőtárolása mérsékli a C-vitamin tartalom csökkenés mértékét a szobahőfokon történő tárolással összehasonlítva. A 100% gyümölcshányadú narancslevek C-vitamin tartalma mintegy fele-kétharmada a friss narancsra vonatkozó értéknek. A narancslé Cvitamin tartalma és az ár között nem mutatható ki összefüggés. In Hungary orange is the dominant citrus fruit. But during processing some changes occur in the chemical composition of the original fruit, and the vitamin-C content decreases. The cool temperature storage - in comparison with the room temperature one - decreases the measure of the vitamin-C content change. The vitamin-C content of various 100% fruit-ratio containing orange juices is about half or 2/3 of the original fresh orange. There was no correlation between the vitamin-C content and the price of the orange juices
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