88,746 research outputs found
The Transition Probability of the -TAZRP (-Bosons) with Inhomogeneous Jump Rates
In this paper we consider the -deformed totally asymmetric zero range
process (-TAZRP), also known as the -boson (stochastic) particle system,
on the lattice, such that the jump rate of a particle depends on
the site where it is on the lattice. We derive the transition probability for
an particle process in Bethe ansatz form as a sum of -fold contour
integrals. Our result generalizes the transition probability formula by
Korhonen and Lee for -TAZRP with a homogeneous lattice, and our method
follows the same approach as theirs
The microbial zoo in the C. elegans intestine: Bacteria, fungi and viruses
Press freedom has become one of the major challenges facing Journalism practice in the world. This paper explores the factors hindering press freedom in Nigeria using some relevant examples. The researcher used the qualitative method of research; using secondary data comprising of books and journals. The study is embedded on social responsibility theory. The study reveals that there are a lot of factors in Nigeria that hinders press freedom ranging from secrecy, legal pressure, direct censorship and force among others. Findings also reveal that Nigerian press freedom is a paradox and only exist on paper i.e. in the constitution but not in practice. The study recommends that since press freedom is granted in the constitution of Nigeria, there should be statutory backup and in order not to hinder press freedom, journalist should be allowed to have access to government sources and records so long as it will not bring chaos to the society at large
Pollicott's Algorithm for Markovian Products of Positive Matrices
In a recent paper by M. Pollicott, an efficient algorithm was proposed,
applying Ruelle's theory of transfer operators and Grothendieck's classical
work on nuclear operators, to compute the Lyapunov exponent associated with the
i.i.d. products of positive matrices. In this article, we generalise the result
to Markovian products and correct some minor mistakes in Pollicott's original
paper.Comment: 27 page
First-Principles Perturbative Computation of Phonon Properties of Insulators in Finite Electric Fields
We present a perturbative method for calculating phonon properties of an
insulator in the presence of a finite electric field. The starting point is a
variational total-energy functional with a field-coupling term that represents
the effect of the electric field. This total-energy functional is expanded in
small atomic displacements within the framework of density-functional
perturbation theory. The linear response of field-polarized Bloch functions to
atomic displacements is obtained by minimizing the second-order derivatives of
the total-energy functional. In the general case of nonzero phonon wavevector,
there is a subtle interplay between the couplings between neighboring k-points
introduced by the presence of the electric field in the reference state, and
further-neighbor k-point couplings determined by the wavevector of the phonon
perturbation. As a result, terms arise in the perturbation expansion that take
the form of four-sided loops in k-space. We implement the method in the {\tt
ABINIT} code and perform illustrative calculations of the field-dependent
phonon frequencies for III-V semiconductors
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