9,307 research outputs found
The internal composition of proto-neutron stars under strong magnetic fields
In this work, we study the effects of magnetic fields and rotation on the
structure and composition of proto-neutron stars (PNS's). A hadronic chiral
SU(3) model is applied to cold neutron stars (NS) and proto-neutron stars with
trapped neutrinos and at fixed entropy per baryon. We obtain general
relativistic solutions for neutron and proto-neutron stars endowed with a
poloidal magnetic field by solving Einstein-Maxwell field equations in a
self-consistent way. As the neutrino chemical potential decreases in value over
time, this alters the chemical equilibrium and the composition inside the star,
leading to a change in the structure and in the particle population of these
objects. We find that the magnetic field deforms the star and significantly
alters the number of trapped neutrinos in the stellar interior, together with
strangeness content and temperature in each evolution stage.Comment: Accepted for publication in PR
Balanced Boolean functions that can be evaluated so that every input bit is unlikely to be read
A Boolean function of n bits is balanced if it takes the value 1 with
probability 1/2. We exhibit a balanced Boolean function with a randomized
evaluation procedure (with probability 0 of making a mistake) so that on
uniformly random inputs, no input bit is read with probability more than
Theta(n^{-1/2} sqrt{log n}). We give a balanced monotone Boolean function for
which the corresponding probability is Theta(n^{-1/3} log n). We then show that
for any randomized algorithm for evaluating a balanced Boolean function, when
the input bits are uniformly random, there is some input bit that is read with
probability at least Theta(n^{-1/2}). For balanced monotone Boolean functions,
there is some input bit that is read with probability at least Theta(n^{-1/3}).Comment: 11 page
Integral Launch and Reentry Vehicle - Executive Summary Final Report
Characteristics of integral launch and reentry vehicles - executive summar
Many-body forces in magnetic neutron stars
In this work, we study in detail the effects of many-body forces on the
equation of state and the structure of magnetic neutron stars. The stellar
matter is described within a relativistic mean field formalism that takes into
account many-body forces by means of a non-linear meson field dependence on the
nuclear interaction coupling constants. We assume that matter is at zero
temperature, charge neutral, in beta-equilibrium, and populated by the baryon
octet, electrons, and muons. In order to study the effects of different degrees
of stiffness in the equation of state, we explore the parameter space of the
model, which reproduces nuclear matter properties at saturation, as well as
massive neutron stars. Magnetic field effects are introduced both in the
equation of state and in the macroscopic structure of stars by the
self-consistent solution of the Einstein-Maxwell equations. In addition,
effects of poloidal magnetic fields on the global properties of stars, as well
as density and magnetic field profiles are investigated. We find that not only
different macroscopic magnetic field distributions, but also different
parameterizations of the model for a fixed magnetic field distribution impact
the gravitational mass, deformation and internal density profiles of stars.
Finally, we also show that strong magnetic fields affect significantly the
particle populations of starsComment: accepted by The Astrophysical Journa
Critical curves in conformally invariant statistical systems
We consider critical curves -- conformally invariant curves that appear at
critical points of two-dimensional statistical mechanical systems. We show how
to describe these curves in terms of the Coulomb gas formalism of conformal
field theory (CFT). We also provide links between this description and the
stochastic (Schramm-) Loewner evolution (SLE). The connection appears in the
long-time limit of stochastic evolution of various SLE observables related to
CFT primary fields. We show how the multifractal spectrum of harmonic measure
and other fractal characteristics of critical curves can be obtained.Comment: Published versio
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