9,926 research outputs found
First principle theory of correlated transport through nano-junctions
We report the inclusion of electron-electron correlation in the calculation
of transport properties within an ab initio scheme. A key step is the
reformulation of Landauer's approach in terms of an effective transmittance for
the interacting electron system. We apply this framework to analyze the effect
of short range interactions on Pt atomic wires and discuss the coherent and
incoherent correction to the mean-field approach.Comment: 5 pages, 3 figure
Chiral Extensions of the MSSM
We present a class of extensions of the MSSM characterized by a fully chiral
field content (no mu-terms) and no baryon or lepton number violating term in
the superpotential due to an extra U'(1) gauge symmetry. The minimal model
consist of the usual matter sector with family dependent U'(1) charges, six
Higgs weak doublets, and three singlets required to give masses to the
Higgsinos and cancel anomalies. We discuss its main features such as the tree
level mass spectrum and the constraints on flavor changing processes.Comment: 13 pages. V2: Superpotential and U'(1) charges changed. Analysis of
the spectrum for the new model added. References update
Absorption of dilaton s-wave in type 0B string theory
We find the absorption probability of dilaton field in type 0B string theory.
Since the background solutions are of the form on both
regions, we use the semiclassical formalism adopted in type IIB theory to find
the absorption cross section. The background tachyon field solution was used as
a reference to relate the solutions of the two regions. We also consider the
possible corrections to absorption probability and the form of the
correction is expected as in the calculation of the confinement solution.Comment: minor corrections, reference added, version to appear PR
Beta-functions in Yang-Mills Theory from Non-critical String
The renormalization group equations of the Yang-Mills theory are examined in
the non-critical string theory according to the framework of the holography.
Under a simple ansatz for the tachyon, we could find several interesting
solutions which are classified by the value of the tachyon potential at the
vacuum. We show two typical, asymptotic-free solutions which are different in
their infrared behaviors. For both types of solutions, we could obtain
quark-confinement potential from the Wilson-loop. The stability of the tachyon
and the ZigZag symmetry are also discussed for these solutions.Comment: 16 pages, 5 figure
Yang-Mills theory from non-critical string
The correspondence of the non-critical string theory and the Yang-Mills
theory is examined according to the recent Polyakov's proposal, and two
possible solutions of the bulk equations are addressed near the fixed points of
the pure Yang-Mills theory: (i) One solution asymptotically approaches to the
AdS space at the ultraviolet limit where the conformally invariant field theory
is realized. (ii) The second one approaches to the flat space in both the
infrared and the ultraviolet limits. The area law of the Wilson-loop and the
asymptotic freedom with logarithmic behaviour are seen in the respective limit.Comment: 17 pages, no figure, Late
On the Complex Network Structure of Musical Pieces: Analysis of Some Use Cases from Different Music Genres
This paper focuses on the modeling of musical melodies as networks. Notes of
a melody can be treated as nodes of a network. Connections are created whenever
notes are played in sequence. We analyze some main tracks coming from different
music genres, with melodies played using different musical instruments. We find
out that the considered networks are, in general, scale free networks and
exhibit the small world property. We measure the main metrics and assess
whether these networks can be considered as formed by sub-communities. Outcomes
confirm that peculiar features of the tracks can be extracted from this
analysis methodology. This approach can have an impact in several multimedia
applications such as music didactics, multimedia entertainment, and digital
music generation.Comment: accepted to Multimedia Tools and Applications, Springe
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