906 research outputs found
Dynamical Heterogeneity and Nonlinear Susceptibility in Short-Ranged Attractive Supercooled Liquids
Recent work has demonstrated the strong qualitative differences between the
dynamics near a glass transition driven by short-ranged repulsion and one
governed by short-ranged attraction. Here, we study in detail the behavior of
non-linear, higher-order correlation functions that measure the growth of
length scales associated with dynamical heterogeneity in both types of systems.
We find that this measure is qualitatively different in the repulsive and
attractive cases with regards to the wave vector dependence as well as the time
dependence of the standard non-linear four-point dynamical susceptibility. We
discuss the implications of these results for the general understanding of
dynamical heterogeneity in glass-forming liquids.Comment: 5 pages, 3 figure
Phase behavior and far-from-equilibrium gelation of charged attractive colloids
In this Rapid Communication we demonstrate the applicability of an augmented
Gibbs ensemble Monte Carlo approach for the phase behavior determination of
model colloidal systems with short-ranged depletion attraction and long-ranged
repulsion. This technique allows for a quantitative determination of the phase
boundaries and ground states in such systems. We demonstrate that gelation may
occur in systems of this type as the result of arrested microphase separation,
even when the equilibrium state of the system is characterized by compact
microphase structures.Comment: 5 pages, 3 figures, final versio
Comment on "Layering transition in confined molecular thin films: Nucleation and growth"
When fluid is confined between two molecularly smooth surfaces to a few
molecular diameters, it shows a large enhancement of its viscosity. From
experiments it seems clear that the fluid is squeezed out layer by layer. A
simple solution of the Stokes equation for quasi-two-dimensional confined flow,
with the assmption of layer-by-layer flow is found. The results presented here
correct those in Phys. Rev. B, 50, 5590 (1994), and show that both the
kinematic viscosity of the confined fluid and the coefficient of surface drag
can be obtained from the time dependence of the area squeezed out. Fitting our
solution to the available experimental data gives the value of viscosity which
is ~7 orders of magnitude higher than that in the bulk.Comment: 4 pages, 2 figure
A Fully Self-Consistent Treatment of Collective Fluctuations in Quantum Liquids
The problem of calculating collective density fluctuations in quantum liquids
is revisited. A fully quantum mechanical self-consistent treatment based on a
quantum mode-coupling theory [E. Rabani and D.R. Reichman, J. Chem. Phys.116,
6271 (2002)] is presented. The theory is compared with the maximum entropy
analytic continuation approach and with available experimental results. The
quantum mode-coupling theory provides semi-quantitative results for both short
and long time dynamics. The proper description of long time phenomena is
important in future study of problems related to the physics of glassy quantum
systems, and to the study of collective fluctuations in Bose fluids.Comment: 9 pages, 4 figure
Theoretical investigation of electron-hole complexes in anisotropic two-dimensional materials
Trions and biexcitons in anisotropic two-dimensional materials are
investigated within an effective mass theory. Explicit results are obtained for
phosphorene and arsenene, materials that share features such as a direct
quasi-particle gap and anisotropic conduction and valence bands. Trions are
predicted to have remarkably high binding energies and an elongated
electron-hole structure with a preference for alignment along the armchair
direction, where the effective masses are lower. We find that biexciton binding
energies are also notably large, especially for monolayer phosphorene, where
they are found to be twice as large as those for typical monolayer transition
metal dichalcogenides.Comment: 3 figures, 5 pages + Supplementary Material, accepted for publication
in Phys. Rev.
Systematic characterization of thermodynamic and dynamical phase behavior in systems with short-ranged attraction
In this paper we demonstrate the feasibility and utility of an augmented
version of the Gibbs ensemble Monte Carlo method for computing the phase
behavior of systems with strong, extremely short-ranged attractions. For
generic potential shapes, this approach allows for the investigation of
narrower attractive widths than those previously reported. Direct comparison to
previous self-consistent Ornstein-Zernike approximation calculations are made.
A preliminary investigation of out-of-equilibrium behavior is also performed.
Our results suggest that the recent observations of stable cluster phases in
systems without long-ranged repulsions are intimately related to gas-crystal
and metastable gas-liquid phase separation.Comment: 10 pages, 8 figure
Out-of-equilibrium dynamical fluctuations in glassy systems
In this paper we extend the earlier treatment of out-of-equilibrium
mesoscopic fluctuations in glassy systems in several significant ways. First,
via extensive simulations, we demonstrate that models of glassy behavior
without quenched disorder display scalings of the probability of local two-time
correlators that are qualitatively similar to that of models with short-ranged
quenched interactions. The key ingredient for such scaling properties is shown
to be the development of a critical-like dynamical correlation length, and not
other microscopic details. This robust data collapse may be described in terms
of a time-evolving Gumbel-like distribution. We develop a theory to describe
both the form and evolution of these distributions based on a effective
sigma-model approach.Comment: 20 pages, RevTex, 9 figure
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