159 research outputs found
Desiccation of a clay film: Cracking versus peeling
Cracking and peeling of a layer of clay on desiccation has been simulated
using a spring model. A vertical section through the layer with finite
thickness is represented by a rectangular array of nodes connected by linear
springs on a square lattice. The effect of reduction of the natural length of
the springs, which mimics the drying is studied. Varying the strength of
adhesion between sample and substrate and the rate of penetration of the drying
front produces an interesting phase diagram, showing cross-over from peeling to
cracking behavior. Changes in the number and width of cracks on varying the
layer thickness is observed to reproduce experimental reports.Comment: 4 figure
Dynamics of market states and risk assessment
Based on previous developments of the concept of market states using
correlation matrices, in the present paper we address the dynamical evolution
of correlation matrices in time. This will imply minor modifications to the
market states themselves, due to increased attention to the transition matrix
between the states. We will introduce trajectories of the correlation matrices
by considering one day shifts for the epoch used to calculate the correlation
matrices and will visualize both the states and the trajectories after
dimensional scaling. This approach using dynamics improves the options of risk
assessment and opens the door to dynamical treatments of markets and shows
noise suppression in a new light.Comment: 22 pages and 27 figures. arXiv admin note: text overlap with
arXiv:2003.0705
Static and dynamical quantum correlations in phases of an alternating field XY model
We investigate the static and dynamical patterns of entanglement in an
anisotropic XY model with an alternating transverse magnetic field, which is
equivalent to a two-component one-dimensional Fermi gas on a lattice, a system
realizable with current technology. Apart from the antiferromagnetic and
paramagnetic phases, the model possesses a dimer phase which is not present in
the transverse XY model. At zero temperature, we find that the first derivative
of bipartite entanglement can detect all the three phases. We analytically show
that the model has a "factorization line" on the plane of system parameters, in
which the zero temperature state is separable. Along with investigating the
effect of temperature on entanglement in a phase plane, we also report a
non-monotonic behavior of entanglement with respect to temperature in the
anti-ferromagnetic and paramagnetic phases, which is surprisingly absent in the
dimer phase. Since the time dynamics of entanglement in a realizable physical
system plays an important role in quantum information processing tasks, the
evolutions of entanglement at small as well as large time are examined.
Consideration of large time behavior of entanglement helps us to prove that in
this model, entanglement is always ergodic. We observe that other quantum
correlation measures can qualitatively show similar features in zero and finite
temperatures. However, unlike nearest-neighbor entanglement, the
nearest-neighbor information theoretic measures can be both ergodic as well as
non-ergodic, depending on the system parameters.Comment: 20 Pages, 13 Figures, 2 Tables, Published versio
Classical integrability in the BTZ black hole
Using the fact the BTZ black hole is a quotient of AdS_3 we show that
classical string propagation in the BTZ background is integrable. We construct
the flat connection and its monodromy matrix which generates the non-local
charges. From examining the general behaviour of the eigen values of the
monodromy matrix we determine the set of integral equations which constrain
them. These equations imply that each classical solution is characterized by a
density function in the complex plane. For classical solutions which correspond
to geodesics and winding strings we solve for the eigen values of the monodromy
matrix explicitly and show that geodesics correspond to zero density in the
complex plane. We solve the integral equations for BMN and magnon like
solutions and obtain their dispersion relation. Finally we show that the set of
integral equations which constrain the eigen values of the monodromy matrix can
be identified with the continuum limit of the Bethe equations of a twisted
SL(2, R) spin chain at one loop.Comment: 45 pages, Reference added, typos corrected, discussion on geodesics
improved to include all geodesic
Observation of the competing fission modes in 178 Pt
Fragment mass distributions from fission of the excited compound nucleus 178 Pt have been deduced from the measured fragment velocities. The 178 Pt nucleus was created at the JAEA tandem facility in a complete fusion reaction 36 Ar + 142 Nd, at beam energies of 155, 170 and 180 MeV. The data are indicative of a mixture of the mass-asymmetric and mass-symmetric fission modes associated with higher and lower total kinetic energies of the fragments, respectively. The measured fragment yields are dominated by asymmetric mass splits, with the symmetric mode contributing at the level of ≈1/3. This constitutes the first observation of a multimodal fission in the sub-lead region. Most probable experimental fragment-mass split of the asymmetric mode, A L /A H ≈79/99, is well reproduced by nuclear density functional theory using the UNEDF1-HFB and D1S potentials. The symmetric mode is associated by theory with very elongated fission fragments, which is consistent with the observed total kinetic energy/fragment mass correlation
ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity.This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges
Bright Side of Lignin Depolymerization:Toward New Platform Chemicals
Lignin,
a major component of lignocellulose, is the largest source
of aromatic building blocks on the planet and harbors great potential
to serve as starting material for the production of biobased products.
Despite the initial challenges associated with the robust and irregular
structure of lignin, the valorization of this intriguing aromatic
biopolymer has come a long way: recently, many creative strategies
emerged that deliver defined products via catalytic or biocatalytic
depolymerization in good yields. The purpose of this review is to
provide insight into these novel approaches and the potential application
of such emerging new structures for the synthesis of biobased polymers
or pharmacologically active molecules. Existing strategies for functionalization
or defunctionalization of lignin-based compounds are also summarized.
Following the whole value chain from raw lignocellulose through depolymerization
to application whenever possible, specific lignin-based compounds
emerge that could be in the future considered as potential lignin-derived
platform chemicals
ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider
ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges
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