35,721 research outputs found
Driven Disordered Polymorphic Solids: Phases and Phase Transitions, Dynamical Coexistence and Peak Effect Anomalies
We study a model for the depinning and driven steady state phases of a solid
tuned across a polymorphic phase transition between ground states of triangular
and square symmetry. These include pinned states which may have dominantly
triangular or square correlations, a plastically flowing liquid-like phase, a
moving phase with hexatic correlations, flowing triangular and square states
and a dynamic coexistence regime characterized by the complex interconversion
of locally square and triangular regions. We locate these phases in a dynamical
phase diagram. We demonstrate that the apparent power-law orientational
correlations we obtain in our moving hexatic phase arise from circularly
averaging an orientational correlation function with qualitatively different
behaviour in the longitudinal (drive) and transverse directions. The
intermediate coexistence regime exhibits several novel properties, including
substantial enhancement in the current noise, an unusual power-law spectrum of
current fluctuations and striking metastability effects. This noise arises from
the fluctuations of the interface separating locally square and triangular
ordered regions. We demonstrate the breakdown of effective ``shaking
temperature'' treatments in the coexistence regime by showing that such shaking
temperatures are non-monotonic functions of the drive in this regime. Finally
we discuss the relevance of these simulations to the anomalous behaviour seen
in the peak effect regime of vortex lines in the disordered mixed phase of
type-II superconductors. We propose that this anomalous behavior is directly
linked to the behavior exhibited in our simulations in the dynamical
coexistence regime, thus suggesting a possible solution to the problem of the
origin of peak effect anomalies.Comment: 22 pages, double column, higher quality figures available from
author
Electronic and optical properties of SnX2(X=S, Se)-InSe van der Waals heterostructures from first- principle calculations
In this work from first-principles simulations we investigate bilayer van der
Waals heterostructures (vdWh) of emerging 2-dimensional (2D) optical materials
SnS 2 and SnSe 2 with monolayer InSe. With density functional theory (DFT)
calculations, we study the structural, electronic, optical and carrier
transport properties of the SnX 2 (X=S,Se)-InSe vdWh. Calculations show SnX 2
-InSe in its most stable stacking form (named AB-1) to be a material with a
small (0.6- 0.7eV) indirect band-gap. The bilayer vdWh shows broad spectrum
optical response, with number of peaks in the infra-red to visible region. In
terms of carrier transport properties, asymmetry in conductance was observed
with respect to the transport direction and electron and hole transmission. The
findings are promising from the viewpoint of nanoelectronics and photonics.Comment: The following article has been submitted for peer-review. After it is
published, it will be found at Lin
Investigating Antigram Behaviour using Distributional Semantics
Language is an extremely interesting subject to study, each day presenting
new challenges and new topics for research. Words in particular have several
unique characteristics which when explored, prove to be astonishing. Anagrams
and Antigrams are such words possessing these amazing properties. The presented
work is an exploration into generating anagrams from a given word and
determining whether there exists antigram relationships between the pairs of
generated anagrams in light of the Word2Vec distributional semantic similarity
model. The experiments conducted, showed promising results for detecting
antigrams.Comment: 4 page
Confronting the Inert Doublet Model with results from Run 1 of the LHC
The Inert Doublet Model (IDM) is a simple extension of the Standard Model
(SM) that aims to address the naturalness problem, electroweak baryogenesis and
accommodate a viable dark matter (DM) candidate, along with a rich phenomenlogy
in terms of collider signatures. In this note, we address the constraints on
the IDM by recasting dilepton + missing energy searches performed for
Supersymmetry at LHC run-1 using Madanalysis5.Comment: Contribution to the 18th International Conference From the Planck
Scale to the Electroweak Scale, Ioannina, Greece. (admin note :Text overlap
with arXiv: 1503.07367
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