6,683 research outputs found
Landscape Paradigms in Physics and Biology: Introduction and Overview
A brief introductory overview in general terms is given of concepts, issues
and applications of the paradigm of rugged landscapes in the contexts of
physics and biology.Comment: 10 pages, to be published in Physica
Spin Glasses: a Perspective
A brief personal perspective is given of issues, questions, formulations,
methods, some answers and selected extensions posed by the spin glass problem,
showing how considerations of an apparently insignificant and practically
unimportant group of metallic alloys stimulated an explosion of new insights
and opportunities in the general area of complex many-body systems and still is
doing soComment: For publication in the proceedings of International Conference on
"Equilibrium and Dynamics of Spin Glasses" (Ascona, Switzerland: April 2004).
V2 has minor changes to clarify and correct typo
The Minority Game: a statistical physics perspective
A brief review is given of the minority game, an idealized model stimulated
by a market of speculative agents, and its complex many-body behaviour.
Particular consideration is given to analytic results for the model rather than
discussions of its relevance in real-world situations.Comment: 6 pages, 2 figures. Submitted for publication in the proceedings of
the Econophysics Colloquium, Canberra, Australia (November 2005
On exact mappings between fermionic Ising spin glass and classical spin glass models
We present in this paper exact analytical expressions for the thermodynamical
properties and Green functions of a certain family of fermionic Ising
spin-glass models with Hubbard interaction, by noticing that their Hamiltonian
is a function of the number operator only. The thermodynamical properties are
mapped to the classical Ghatak-Sherrington spin-glass model while the the
Density of States (DoS) is related to its joint spin-field distribution. We
discuss the presence of the pseudogap in the DoS with the help of this mapping.Comment: 6 page
Irreducible free energy expansion and overlaps locking in mean field spin glasses
We introduce a diagrammatic formulation for a cavity field expansion around
the critical temperature. This approach allows us to obtain a theory for the
overlap's fluctuations and, in particular, the linear part of the
Ghirlanda-Guerra relationships (GG) (often called Aizenman-Contucci polynomials
(AC)) in a very simple way. We show moreover how these constraints are
"superimposed" by the symmetry of the model with respect to the restriction
required by thermodynamic stability. Within this framework it is possible to
expand the free energy in terms of these irreducible overlaps fluctuations and
in a form that simply put in evidence how the complexity of the solution is
related to the complexity of the entropy.Comment: 19 page
Glassy dynamics in the HMF model
We discuss the glassy dynamics recently found in the meta-equilibrium quasi
stationary states (QSS) of the HMF model. The relevance of the initial
conditions and the connection with Tsallis nonextensive thermostatistics is
also addressed.Comment: 10 pages, 4 figures, Proceedings of the Int. Conference Next2003
21-28 september 2003, Villasimius (CA) Italy, submitted to Physica
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