2,300 research outputs found
Biology helps you to win a game
We present a game of interacting agents which mimics the complex dynamics
found in many natural and social systems. These agents modify their strategies
periodically, depending on their performances using genetic crossover
mechanisms, inspired by biology. We study the performances of the agents under
different conditions, and how they adapt themselves. In addition the dynamics
of the game is investigated.Comment: 4 pages including 6 figures. Uses REVTeX4. Submitted for Conference
Proceedings of the "Unconventional Applications of Statistical Physics",
Kolkat
Interaction of quasilocal harmonic modes and boson peak in glasses
The direct proportionality relation between the boson peak maximum in
glasses, , and the Ioffe-Regel crossover frequency for phonons,
, is established. For several investigated materials . At the frequency the mean free path of the
phonons becomes equal to their wavelength because of strong resonant
scattering on quasilocal harmonic oscillators. Above this frequency phonons
cease to exist. We prove that the established correlation between
and holds in the general case and is a direct consequence of
bilinear coupling of quasilocal oscillators with the strain field.Comment: RevTex, 4 pages, 1 figur
Testing the Equivalence of Regular Languages
The minimal deterministic finite automaton is generally used to determine
regular languages equality. Antimirov and Mosses proposed a rewrite system for
deciding regular expressions equivalence of which Almeida et al. presented an
improved variant. Hopcroft and Karp proposed an almost linear algorithm for
testing the equivalence of two deterministic finite automata that avoids
minimisation. In this paper we improve the best-case running time, present an
extension of this algorithm to non-deterministic finite automata, and establish
a relationship between this algorithm and the one proposed in Almeida et al. We
also present some experimental comparative results. All these algorithms are
closely related with the recent coalgebraic approach to automata proposed by
Rutten
Comparison of 'shallow' and 'deep' junction architectures for MBE-grown InAs/GaAs quantum dot solar cells
We report on the fabrication of InAs/GaAs quantum dot solar cells with high open circuit voltage by molecular beam epitaxy. `Shallow' and `deep' junction architectures were compared. The highest open circuit voltage of 0.94 V was obtained for the `shallow' junction configuration. The open circuit voltage of InAs quantum dot solar cells decreased only by ~40 mV compared to GaAs reference cells for both junction architectures indicating high quality quantum dots. The open circuit voltage of InAs/GaAs quantum dot solar cells was also found to be dependent on the size of quantum dots
Checking NFA equivalence with bisimulations up to congruence
16pInternational audienceWe introduce bisimulation up to congruence as a technique for proving language equivalence of non-deterministic finite automata. Exploiting this technique, we devise an optimisation of the classical algorithm by Hopcroft and Karp. We compare our algorithm to the recently introduced antichain algorithms, by analysing and relating the two underlying coinductive proof methods. We give concrete examples where we exponentially improve over antichains; experimental results moreover show non negligible improvements on random automata
The Computational Complexity of Generating Random Fractals
In this paper we examine a number of models that generate random fractals.
The models are studied using the tools of computational complexity theory from
the perspective of parallel computation. Diffusion limited aggregation and
several widely used algorithms for equilibrating the Ising model are shown to
be highly sequential; it is unlikely they can be simulated efficiently in
parallel. This is in contrast to Mandelbrot percolation that can be simulated
in constant parallel time. Our research helps shed light on the intrinsic
complexity of these models relative to each other and to different growth
processes that have been recently studied using complexity theory. In addition,
the results may serve as a guide to simulation physics.Comment: 28 pages, LATEX, 8 Postscript figures available from
[email protected]
Periodic orbit theory for realistic cluster potentials: The leptodermous expansion
The formation of supershells observed in large metal clusters can be
qualitatively understood from a periodic-orbit-expansion for a spherical
cavity. To describe the changes in the supershell structure for different
materials, one has, however, to go beyond that simple model. We show how
periodic-orbit-expansions for realistic cluster potentials can be derived by
expanding only the classical radial action around the limiting case of a
spherical potential well. We give analytical results for the leptodermous
expansion of Woods-Saxon potentials and show that it describes the shift of the
supershells as the surface of a cluster potential gets softer. As a byproduct
of our work, we find that the electronic shell and supershell structure is not
affected by a lattice contraction, which might be present in small clusters.Comment: 15 pages RevTex, 11 eps figures, additional information at
http://www.mpi-stuttgart.mpg.de/docs/ANDERSEN/users/koch/Diss
Implementing Shor's algorithm on Josephson Charge Qubits
We investigate the physical implementation of Shor's factorization algorithm
on a Josephson charge qubit register. While we pursue a universal method to
factor a composite integer of any size, the scheme is demonstrated for the
number 21. We consider both the physical and algorithmic requirements for an
optimal implementation when only a small number of qubits is available. These
aspects of quantum computation are usually the topics of separate research
communities; we present a unifying discussion of both of these fundamental
features bridging Shor's algorithm to its physical realization using Josephson
junction qubits. In order to meet the stringent requirements set by a short
decoherence time, we accelerate the algorithm by decomposing the quantum
circuit into tailored two- and three-qubit gates and we find their physical
realizations through numerical optimization.Comment: 12 pages, submitted to Phys. Rev.
On Measuring Non-Recursive Trade-Offs
We investigate the phenomenon of non-recursive trade-offs between
descriptional systems in an abstract fashion. We aim at categorizing
non-recursive trade-offs by bounds on their growth rate, and show how to deduce
such bounds in general. We also identify criteria which, in the spirit of
abstract language theory, allow us to deduce non-recursive tradeoffs from
effective closure properties of language families on the one hand, and
differences in the decidability status of basic decision problems on the other.
We develop a qualitative classification of non-recursive trade-offs in order to
obtain a better understanding of this very fundamental behaviour of
descriptional systems
The role of culture and society in the development of plot in tanushree podders escape from harem and gita mehtas a river sutra: a feminist reading
Culture and Society are often the main gist of most novels. These two factors often influence and control the characters, thus helping in the development of the plot. A plot, as defined by Egan (1978), is used to indicate an outline of events and serves as a skeleton in a literary piece. In other words, it is a tool in making sure the main incidents or scenarios are presented in a particular order to establish a clear understanding of what is being written. Culture and society plays the essence in a novel as it constructs these main ideas in engaging the interest of a reader and also extends the intended message of the particular writer. This paper looks into how culture and society helps in developing the plots of the selected novels using the feminist approach. Tanushree Podder’s, Escape from Harem (2013) and Gita Mehta’s A River Sutra (1993) amazingly are both set in India. Podder and Mehta have inserted the perception society had over women and how male supremacy was glorified in many aspects. The essence of feminist approach was very much present in these two novels. According to Tyson (2006), feminism concerns the ways in which literature undermines the economic, political, social and psychological oppression on women. Though the setting of both novels fall in different eras but the theme of female oppression remains the same. The patriarchal society uses culture and religion as a tool to control women and oppress them. Both authors have shown how the women in the 17th century and in the 20th century face the same kind of judgment from the society and men in general
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