8,472 research outputs found
Constrained Molecular Dynamics II: a N-body approach to nuclear systems
In this work we illustrate the basic development of the constrained molecular
dynamics applied to the N-body problem in nuclear physics. The heavy
computational taskes related to quantum effects, to the presence of the "hard
core" repulsive interaction have been worked out by defining a set of
transformations based on the concept of impulsive forces. In particular in the
implemented version II of the Constrained Molecular Dynamics model the problem
related to the non conservation of the total angular momentum has been solved.
This problem can affect others semiclassical microscopic approaches as due to
the "hard core" repulsive interaction or to the use of stochastic forces. The
effect of the restored conservation law on the fusion cross section for
40Ca+40Ca system is also briefly discussed.Comment: Tex version 3.1459 (Web2C 7.3.1);main text+fig.cap in .tex 13 page;
+4 figures .ps;the order and the numerical label of the figure files reflect
the figure numbers in the main tex and captions, Submited to Journal of
computational physic
End-to-end algorithm for hierarchical area searches for long-duration GW sources for GEO 600
We describe a hierarchical, highly parallel computer algorithm to perform
searches for unknown sources of continuous gravitational waves -- spinning
neutron stars in the Galaxy -- over wide areas of the sky and wide frequency
bandwidths. We optimize the algorithm for an observing period of 4 months and
an available computing power of 20 Gflops, in a search for neutron stars
resembling millisecond pulsars. We show that, if we restrict the search to the
galactic plane, the method will detect any star whose signal is stronger than
15 times the noise level of a detector over that search period. Since
on grounds of confidence the minimum identifiable signal should be about 10
times noise, our algorithm does only 50% worse than this and runs on a computer
with achievable processing speed.Comment: 7 pages, for proceedings of Jan 1999 Moriond meeting "Gravitational
Waves and Experimental Gravity
Searching for continuous gravitational wave signals: the hierarchical Hough transform algorithm
It is well known that matched filtering techniques cannot be applied for
searching extensive parameter space volumes for continuous gravitational wave
signals. This is the reason why alternative strategies are being pursued.
Hierarchical strategies are best at investigating a large parameter space when
there exist computational power constraints. Algorithms of this kind are being
implemented by all the groups that are developing software for analyzing the
data of the gravitational wave detectors that will come online in the next
years. In this talk we will report about the hierarchical Hough transform
method that the GEO 600 data analysis team at the Albert Einstein Institute is
developing. The three step hierarchical algorithm has been described elsewhere.
In this talk we will focus on some of the implementational aspects we are
currently concerned with.Comment: 9 pages, 1 figure. To appear in the proceedings of the conference
``Gravitational waves: a challenge to theoretical astrophysics'', (June 5-9
2000, Trieste), ICTP Lecture Notes Serie
Analytical continuation from imaginary to real chemical potential in 2-color QCD under scrutiny
The method of analytical continuation from imaginary to real chemical
potential is tested in 2-color QCD. In comparison to previous studies in the
same theory, an exact updating algorithm is used and simulations are performed
closer to the thermodynamic limit. It is shown that the method considerably
improves if suitable functions are used to interpolate data with imaginary
chemical potential.Comment: 7 pages, 5 figures, Lattice 2006 (High Temperature and Density
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