1,782 research outputs found
The Imago Primi Saeculi Societatis Iesv (1640). Devotion, Politics and the Emblem.
The Imago Primi Saeculi Societatis Iesv (1640) is, perhaps, the most beautiful book of emblems published by the Jesuits in the seventeenth century. The book is a festive commemoration offered by the priests and students of the Flemish-Belgian Province in celebration of the centenary of the founding of the Society of Jesus. The work includes 127 full-page emblems distributed throughout a total of 956 folio-sized pages that narrate and illustrate in emblematic fashion the foundation, development, vicisstitudes and achievements of the Socirty in its evangelical and pedagogical mission. From the moment of its publication, the Imago was the object of attacks by Huguenauts and Jansenists who criticized its haughtiness, grandiloquent language and the hyperbolic comparisons of the narration. Hidden behind this criticism were the reasons for the Jansenist offensive against the book. Probabilism, the supposed frivolous attitude towards confession and the frequency of communion, advocated by the Jesuits, was the object of a pair of insulting treatises directed against the Imago by the famous Jansenists Antoine Arnauld and Issac Louis le MaĂźtre de Sacy. The critics of the Imago maliciously ignored that the book's grandiloquent style, appropriate to a jubilation celebration, conforms to the language of classical rhetoric, thus perpetuating the propagandistic image of the book. KEYWORDS: Imago Primi Saeculi; Society of Jesus; Flanders; Flemish-Belgian Province
Enhancement of magnetic anisotropy barrier in long range interacting spin systems
Magnetic materials are usually characterized by anisotropy energy barriers
which dictate the time scale of the magnetization decay and consequently the
magnetic stability of the sample. Here we present a unified description, which
includes coherent rotation and nucleation, for the magnetization decay in
generic anisotropic spin systems. In particular, we show that, in presence of
long range exchange interaction, the anisotropy energy barrier grows as the
volume of the particle for on site anisotropy, while it grows even faster than
the volume for exchange anisotropy, with an anisotropy energy barrier
proportional to , where is the particle volume, is the range of interaction and is the embedding dimension. These
results shows a relevant enhancement of the anisotropy energy barrier w.r.t.
the short range case, where the anisotropy energy barrier grows as the particle
cross sectional area for large particle size or large particle aspect ratio.Comment: 7 pages, 6 figures. Theory of Magnetic decay in nanosystem. Non
equilibrium statistical mechanics of many body system
Microcanonical Analysis of Exactness of the Mean-Field Theory in Long-Range Interacting Systems
Classical spin systems with nonadditive long-range interactions are studied
in the microcanonical ensemble. It is expected that the entropy of such a
system is identical to that of the corresponding mean-field model, which is
called "exactness of the mean-field theory". It is found out that this
expectation is not necessarily true if the microcanonical ensemble is not
equivalent to the canonical ensemble in the mean-field model. Moreover,
necessary and sufficient conditions for exactness of the mean-field theory are
obtained. These conditions are investigated for two concrete models, the
\alpha-Potts model with annealed vacancies and the \alpha-Potts model with
invisible states.Comment: 23 pages, to appear in J. Stat. Phy
Canonical solution of a system of long-range interacting rotators on a lattice
The canonical partition function of a system of rotators (classical X-Y
spins) on a lattice, coupled by terms decaying as the inverse of their distance
to the power alpha, is analytically computed. It is also shown how to compute a
rescaling function that allows to reduce the model, for any d-dimensional
lattice and for any alpha<d, to the mean field (alpha=0) model.Comment: Initially submitted to Physical Review Letters: following referees'
Comments it has been transferred to Phys. Rev. E, because of supposed no
general interest. Divided into sections, corrections in (5) and (20),
reference 5 updated. 8 pages 1 figur
Canonical Solution of Classical Magnetic Models with Long-Range Couplings
We study the canonical solution of a family of classical spin
models on a generic -dimensional lattice; the couplings between two spins
decay as the inverse of their distance raised to the power , with
. The control of the thermodynamic limit requires the introduction of
a rescaling factor in the potential energy, which makes the model extensive but
not additive. A detailed analysis of the asymptotic spectral properties of the
matrix of couplings was necessary to justify the saddle point method applied to
the integration of functions depending on a diverging number of variables. The
properties of a class of functions related to the modified Bessel functions had
to be investigated. For given , and for any , and lattice
geometry, the solution is equivalent to that of the model, where the
dimensionality and the geometry of the lattice are irrelevant.Comment: Submitted for publication in Journal of Statistical Physic
An Options-Based Analysis of Emerging Market Exchange Rate Expectations: Brazil's Real Plan, 1994-1997
This paper uses currency option data from the BMF, the Commodities and Futures exchange in Sao Paulo, Brazil, to investigate market expectations on the Brazilian Real-U.S. dollar exchange rate from October 1994 through July 1997. Using options data, we
derive implied probability density functions (PDF) for expected future exchange rates and
thus measures of the credibility of the âcrawling pegâ and target zone (âmaxibandâ)
regimes governing the exchange rate. Since we do not impose an exchange rate model, our analysis is based on either the risk-neutral PDF or arbitrage-based tests of target zones. The paper, one of the first to use options data from an emerging market, finds that
target zone credibility was poor prior to February 1996, but improved afterwards. The
market anticipated periodic band adjustments, but over time developed greater confidence
in the Real. We also test whether devaluation intensities estimated from these option prices can be explained by standard macroeconomic factors
1-d gravity in infinite point distributions
The dynamics of infinite, asymptotically uniform, distributions of
self-gravitating particles in one spatial dimension provides a simple toy model
for the analogous three dimensional problem. We focus here on a limitation of
such models as treated so far in the literature: the force, as it has been
specified, is well defined in infinite point distributions only if there is a
centre of symmetry (i.e. the definition requires explicitly the breaking of
statistical translational invariance). The problem arises because naive
background subtraction (due to expansion, or by "Jeans' swindle" for the static
case), applied as in three dimensions, leaves an unregulated contribution to
the force due to surface mass fluctuations. Following a discussion by
Kiessling, we show that the problem may be resolved by defining the force in
infinite point distributions as the limit of an exponentially screened pair
interaction. We show that this prescription gives a well defined (finite) force
acting on particles in a class of perturbed infinite lattices, which are the
point processes relevant to cosmological N-body simulations. For identical
particles the dynamics of the simplest toy model is equivalent to that of an
infinite set of points with inverted harmonic oscillator potentials which
bounce elastically when they collide. We discuss previous results in the
literature, and present new results for the specific case of this simplest
(static) model starting from "shuffled lattice" initial conditions. These show
qualitative properties (notably its "self-similarity") of the evolution very
similar to those in the analogous simulations in three dimensions, which in
turn resemble those in the expanding universe.Comment: 20 pages, 8 figures, small changes (section II shortened, added
discussion in section IV), matches final version to appear in PR
Dynamical stability criterion for inhomogeneous quasi-stationary states in long-range systems
We derive a necessary and sufficient condition of linear dynamical stability
for inhomogeneous Vlasov stationary states of the Hamiltonian Mean Field (HMF)
model. The condition is expressed by an explicit disequality that has to be
satisfied by the stationary state, and it generalizes the known disequality for
homogeneous stationary states. In addition, we derive analogous disequalities
that express necessary and sufficient conditions of formal stability for the
stationary states. Their usefulness, from the point of view of linear dynamical
stability, is that they are simpler, although they provide only sufficient
criteria of linear stability. We show that for homogeneous stationary states
the relations become equal, and therefore linear dynamical stability and formal
stability become equivalent.Comment: Submitted to Journal of Statistical Mechanics: Theory and Experimen
Relaxation to thermal equilibrium in the self-gravitating sheet model
We revisit the issue of relaxation to thermal equilibrium in the so-called
"sheet model", i.e., particles in one dimension interacting by attractive
forces independent of their separation. We show that this relaxation may be
very clearly detected and characterized by following the evolution of order
parameters defined by appropriately normalized moments of the phase space
distribution which probe its entanglement in space and velocity coordinates.
For a class of quasi-stationary states which result from the violent relaxation
of rectangular waterbag initial conditions, characterized by their virial ratio
R_0, we show that relaxation occurs on a time scale which (i) scales
approximately linearly in the particle number N, and (ii) shows also a strong
dependence on R_0, with quasi-stationary states from colder initial conditions
relaxing much more rapidly. The temporal evolution of the order parameter may
be well described by a stretched exponential function. We study finally the
correlation of the relaxation times with the amplitude of fluctuations in the
relaxing quasi-stationary states, as well as the relation between temporal and
ensemble averages.Comment: 37 pages, 24 figures; some additional discussion of previous
literature and other minor modifications, final published versio
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