62 research outputs found
The Fully Frustrated Hypercubic Model is Glassy and Aging at Large
We discuss the behavior of the fully frustrated hypercubic cell in the
infinite dimensional mean-field limit. In the Ising case the system undergoes a
glass transition, well described by the random orthogonal model. Under the
glass temperature aging effects show clearly. In the case there is no sign
of a phase transition, and the system is always a paramagnet.Comment: Figures added in uufiles format, and epsf include
Stripe glasses: self generated randomness in a uniformly frustrated system
We show that a system with competing interactions on different length scales,
as relevant for the formation of stripes in doped Mott insulators, undergoes a
self-generated glass transition which is caused by the frustrated nature of the
interactions and not related to the presence of quenched disorder. An
exponentially large number of metastable configurations is found, leading to a
slow, landscape dominated long time relaxation and a break up of the system
into a disordered inhomogeneous state.Comment: 5 pages, 2 figure
Statistical Physics of Structural Glasses
This paper gives an introduction and brief overview of some of our recent
work on the equilibrium thermodynamics of glasses. We have focused onto first
principle computations in simple fragile glasses, starting from the two body
interatomic potential. A replica formulation translates this problem into that
of a gas of interacting molecules, each molecule being built of atoms, and
having a gyration radius (related to the cage size) which vanishes at zero
temperature. We use a small cage expansion, valid at low temperatures, which
allows to compute the cage size, the specific heat (which follows the Dulong
and Petit law), and the configurational entropy. The no-replica interpretation
of the computations is also briefly described. The results, particularly those
concerning the Kauzmann tempaerature and the configurational entropy, are
compared to recent numerical simulations.Comment: 21 pages, 6 figures, to appear in the proceedings of the Trieste
workshop on "Unifying Concepts in Glass Physics
Slow dynamics and aging in a non-randomly frustrated spin system
A simple, non-disordered spin model has been studied in an effort to
understand the origin of the precipitous slowing down of dynamics observed in
supercooled liquids approaching the glass transition. A combination of Monte
Carlo simulations and exact calculations indicates that this model exhibits an
entropy vanishing transition accompanied by a rapid divergence of time scales.
Measurements of various correlation functions show that the system displays a
hierarchy of time scales associated with different degrees of freedom. Extended
structures, arising from the frustration in the system, are identified as the
source of the slow dynamics. In the simulations, the system falls out of
equilibrium at a temperature higher than the entropy-vanishing
transition temperature and the dynamics below exhibits aging as
distinct from coarsening. The cooling rate dependence of the energy is also
consistent with the usual glass formation scenario.Comment: 41 pages, 16 figures. Bibliography file is correcte
Self generated randomness, defect wandering and viscous flow in stripe glasses
We show that the competition between interactions on different length scales,
as relevant for the formation of stripes in doped Mott insulators, can cause a
glass transition in a system with no explicitly quenched disorder. We
analytically determine a universal criterion for the emergence of an
exponentially large number of metastable configurations that leads to a finite
configurational entropy and a landscape dominated viscous flow. We demonstrate
that glassines is unambiguously tied to a new length scale which characterizes
the typical length over which defects and imperfections in the stripe pattern
are allowed to wander over long times.Comment: 17 pages, 9 figure
A cold-labile acetyl-coenzyme-A hydrolase from the supernatant fraction of rat liver. Reactivation and reconstitution of the active species from the inactive monomer
Microviscosity and order in the hydrocarbon region of micelles and membranes determined with fluorescent probes. I. Synthetic micelles
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