158,101 research outputs found
Phase Diagram for Nflation
Recently, it was showed that there is a large N phase transition in Nflation,
in which when the number of fields is large enough, the slow roll inflation
phase will disappear. In this brief report, we illustrate the phase diagram for
Nflation, and discuss the entropy bound and some relevant results. It is found
that near the critical point the number of fields saturates dS entropy.Comment: 4 pages, 1 eps figure, contents extended, published versio
Phase Diagram of Li_xFePO_4
The phase diagram for LixFePO4 has been determined for different lithium concentrations and temperatures. The two low-temperature phases, heterosite and triphylite, have previously been shown to transform to a disordered solid solution at elevated temperatures. This disordered phase allows for a continuous transition between the heterosite and triphylite phases and is stable at relatively low temperatures. At intermediate temperatures the proposed phase diagram resembles a eutectoid system, with eutectoid point at around x=0.6 and 200°C. Kinetics of mixing and unmixing transformations are reported, including the hysteresis between heating and cooling. The enthalpy of this transition is at least 700 J/mol
The Granular Phase Diagram
The kinetic energy distribution function satisfying the Boltzmann equation is
studied analytically and numerically for a system of inelastic hard spheres in
the case of binary collisions. Analytically, this function is shown to have a
similarity form in the simple cases of uniform or steady-state flows. This
determines the region of validity of hydrodynamic description. The latter is
used to construct the phase diagram of granular systems, and discriminate
between clustering instability and inelastic collapse. The molecular dynamics
results support analytical results, but also exhibit a novel fluctuational
breakdown of mean-field descriptions.Comment: 15 pages, 4 figure
Global quantum Hall phase diagram from visibility diagrams
We propose a construction of a global phase diagram for the quantum Hall
effect. This global phase diagram is based on our previous constructions of
visibility diagrams in the context of the Quantum Hall Effect. The topology of
the phase diagram we obtain is in good agreement with experimental observations
(when the spin effect can be neglected). This phase diagram does not show
floating.Comment: LaTeX2e, 9 pages, 5 eps figure
New Phase Diagram for Black Holes and Strings on Cylinders
We introduce a novel type of phase diagram for black holes and black strings
on cylinders. The phase diagram involves a new asymptotic quantity called the
relative binding energy. We plot the uniform string and the non-uniform string
solutions in this new phase diagram using data of Wiseman. Intersection rules
for branches of solutions in the phase diagram are deduced from a new Smarr
formula that we derive.Comment: 19 pages, 6 figures, v2: typos corrected, v3: refs. added, comment on
bounds on the relative binding energy n added in end of section
Phase diagram of magnetic polymers
We consider polymers made of magnetic monomers (Ising or Heisenberg-like) in
a good solvent. These polymers are modeled as self-avoiding walks on a cubic
lattice, and the ferromagnetic interaction between the spins carried by the
monomers is short-ranged in space. At low temperature, these polymers undergo a
magnetic induced first order collapse transition, that we study at the mean
field level. Contrasting with an ordinary point, there is a strong
jump in the polymer density, as well as in its magnetization. In the presence
of a magnetic field, the collapse temperature increases, while the
discontinuities decrease. Beyond a multicritical point, the transition becomes
second order and -like. Monte Carlo simulations for the Ising case are
in qualitative agreement with these results.Comment: 29 pages, 15 eps figures (one color figure). Submitted for
publication to Eur.Phys.J.
Ferromagnetism in QCD phase diagram
A possibility and properties of spontaneous magnetization in quark matter are
investigated. Magnetic susceptibility is evaluated within Fermi liquid theory,
taking into account of the screening effect of gluons. Spin wave in the
polarized quark matter, as the Nambu-Goldstone mode, is formulated by way of
the coherent-state path integral.Comment: 9pages,1 figure, Proc. of EXOCT 200
Mapping the QCD Phase Diagram
I review recent theoretical developments which show how a key qualitative
feature of the QCD phase diagram, namely a critical point which in a sense
defines the landscape which heavy ion collision experiments are seeking to map,
can be discovered. The map of the phase diagram which I sketch is based on
reasonable inference from universality, lattice gauge theory and models; the
discovery of the critical point would provide an experimental foundation for
the central qualitative feature of the landscape. I also review recent progress
in our understanding of cold, dense quark matter, as may occur in the cores of
neutron stars. In this regime, quarks form Cooper pairs. The formation of such
superconducting phases requires only weak attractive interactions, as provided
by one-gluon exchange at asymptotically high density; these phases may
nevertheless break chiral symmetry (by locking flavor symmetries to color
symmetry) and may have excitations which are indistinguishable from those in a
confined phase. Mapping this part of the phase diagram will require a better
understanding of how the presence of color superconductivity and color-flavor
locking affects neutron star phenomenology.Comment: Contribution to proceedings of Quark Matter '99, Torino, Italy. 12
pages. 4 figure
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