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5.0

Jun 30, 2018
06/18

by
Arkady Pikovsky; Shamik Gupta; Tarcisio N. Teles; Fernanda P. C. Benetti; Renato Pakter; Yan Levin; Stefano Ruffo

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We explore ensemble inequivalence in long-range interacting systems by studying an XY model of classical spins with ferromagnetic and nematic coupling. We demonstrate the inequivalence by mapping the microcanonical phase diagram onto the canonical one, and also by doing the inverse mapping. We show that the equilibrium phase diagrams within the two ensembles strongly disagree within the regions of first-order transitions, exhibiting interesting features like temperature jumps. In particular, we...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1410.2219

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2.0

Jun 30, 2018
06/18

by
Gabriel A. Canova; Yan Levin; Jeferson J. Arenzon

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We present extensive numerical simulations of a generalized XY model with nematic-like terms recently proposed by Poderoso {\it et al} [PRL 106(2011)067202]. Using finite size scaling and focusing on the $q=3$ case, we locate the transitions between the paramagnetic (P), the nematic-like (N) and the ferromagnetic (F) phases. The results are compared with the recently derived lower bounds for the P-N and P-F transitions. While the P-N transition is found to be very close to the lower bound, the...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1401.4442

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4.0

Jun 30, 2018
06/18

by
Alexandre P. dos Santos; Wagner Figueiredo; Yan Levin

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We develop a simulation method which allows us to calculate the critical micelle concentrations for ionic surfactants in the presence of different salts. The results are in good agreement with the experimental data. The simulations are performed on a simple cubic lattice. The anionic interactions with the alkyl chains are taken into account based on the previously developed theory of the interfacial tensions of hydrophobic interfaces: the kosmotropic anions do not interact with the hydrocarbon...

Topics: Physics, Chemical Physics, Soft Condensed Matter, Biological Physics, Condensed Matter

Source: http://arxiv.org/abs/1404.3237

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Sep 23, 2013
09/13

by
Alexandre Pereira dos Santos; Amin Bakhshandeh; Yan Levin

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We introduce a new method for simulating colloidal suspensions with spherical colloidal particles of dielectric constant different from the surrounding medium. The method uses exact calculation of the Green function to obtain the ion-ion interaction potential in the presence of a dielectric discontinuity at the surface of the colloidal particle. The new method is orders of magnitude faster than the traditional approaches based on series expansions of the interaction potential.

Source: http://arxiv.org/abs/1105.2915v1

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Sep 22, 2013
09/13

by
Yan Levin; Fernando L. da Silveira

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Two identical rubber balloons are partially inflated with air (to different extent) and connected by a hose with a valve. It is found that depending on balloon volumes, when the valve is opened the air will flow either from the larger (fuller) balloon to the smaller (emptier) balloon, or from the smaller balloon to the larger one. The phenomenon is explained in terms of the non-ideal rubber elasticity of balloons. The full phase diagram for the air flow dynamics is constructed.

Source: http://arxiv.org/abs/cond-mat/0403171v1

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Sep 21, 2013
09/13

by
Yan Levin; Renato Pakter

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In a recent paper, Phys. Rev. Lett. 105 260601 (2010) [arXiv:1008.1421], Andrade et al., argued that classical particles confined in a parabolic trap at T=0 distribute themselves in accordance with the Tsallis statistics. To prove their point the authors performed molecular dynamics simulations. Here we show that the model of Andrade et al. can be solved exactly. The distribution of particles at T=0 has nothing to do with the Tsallis entropy and is determined simply by the force balance.

Source: http://arxiv.org/abs/1104.0697v1

4
4.0

Jun 29, 2018
06/18

by
Gabriel A. Canova; Yan Levin; Jeferson J. Arenzon

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We study a generalization of the XY model with an additional nematic-like term through extensive numerical simulations and finite-size techniques, both in two and three dimensions. While the original model favors local alignment, the extra term induces angles of $2\pi/q$ between neighboring spins. We focus here on the $q=8$ case (while presenting new results for other values of $q$ as well) whose phase diagram is much richer than the well known $q=2$ case. In particular, the model presents not...

Topics: Soft Condensed Matter, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1608.07208

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56

Sep 22, 2013
09/13

by
Yan Levin

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A non-perturbative theory is presented which allows to calculate the solvation free energy of polarizable ions near a water-vapor and water-oil interfaces. The theory predicts that larger halogen anions are adsorbed at the interface, while the alkali metal cations are repelled from it. The density profiles calculated theoretically are similar to those obtained using the molecular dynamics simulations with polarizable force fields.

Source: http://arxiv.org/abs/0812.3784v2

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6.0

Jun 30, 2018
06/18

by
Matheus Girotto; Alexandre P. dos Santos; Thiago Colla; Yan Levin

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We study the density distribution of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show that the mean-field theory is able to accurately account for the particle distribution. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. For strongly correlated systems, we construct a density functional theory which provides an excellent description of the particle distribution, without any...

Topics: Soft Condensed Matter, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1405.6129

3
3.0

Jun 30, 2018
06/18

by
Matheus Girotto; Alexandre P. dos Santos; Renato Pakter; Yan Levin

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We argue that contrary to recent suggestions, non-extensive statistical mechanics has no relevance for inhomogeneous systems of particles interacting by short-range potentials. We show that these systems are perfectly well described by the usual Boltzmann-Gibbs statistical mechanics.

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1409.3304

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Sep 24, 2013
09/13

by
Amin Bakhshandeh; Alexandre Pereira dos Santos; Yan Levin

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A theory is presented which allows us to accurately calculate the density profile of monovalent and multivalent counterions in suspensions of polarizable colloids or nano-particles. In the case of monovalent ions, we derive a weak-coupling theory that explicitly accounts for the ion-image interaction, leading to a modified Poisson-Boltzmann equation. For suspensions with multivalent counterions, a strong-coupling theory is used to calculate the density profile near the colloidal surface and a...

Source: http://arxiv.org/abs/1109.4667v1

3
3.0

Jun 29, 2018
06/18

by
Leandro G. Rizzi; Yan Levin

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It is well-known that the swelling behavior of ionic nanogels depends on their cross-link density, however it is unclear how different topologies should affect the response of the polyelectrolyte network. Here we perform Monte Carlo simulations to obtain the equilibrium properties of ionic nanogels as a function of salt concentration $C_s$ and the fraction $f$ of ionizable groups in a polyelectrolyte network formed by cross-links of functionality $z$. Our results indicate that the network with...

Topics: Soft Condensed Matter, Condensed Matter

Source: http://arxiv.org/abs/1603.00917

3
3.0

Jun 30, 2018
06/18

by
Alexandre P. dos Santos; Yan Levin

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We study, using extensive Monte Carlos simulations, the behavior of cationic polyelectrolytes near hydrophobic surfaces in solutions containing Hofmeister salts. The Hofmeister anions are divided into kosmotropes and chaotropes. Near a hydrophobic surface, the chaotropes lose their solvation sheath and become partially adsorbed to the interface, while the kosmotropes remain strongly hydrated and are repelled from the interface. If the polyelectrolyte solution contains chaotropic anions, a...

Topics: Soft Condensed Matter, Condensed Matter

Source: http://arxiv.org/abs/1403.6208

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Sep 24, 2013
09/13

by
N. Lemke; Jeferson J. Arenzon; Yan Levin

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We present a simple model to study micellization of amphiphiles condensed on a rodlike polyion. Although the mean field theory leads to a first order micellization transition for sufficiently strong hydrophobic interactions, the simulations show that no such thermodynamic phase transition exists. Instead, the correlations between the condensed amphiphiles can result in a structure formation very similar to micelles.

Source: http://arxiv.org/abs/cond-mat/0103592v1

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Sep 21, 2013
09/13

by
Paulo S. Kuhn; Yan Levin; Marcia C. Barbosa; Ana Paula Ravazzolo

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A theory is presented which quantitatively accounts for the cooperative adsorption of cationic surfactants to anionic polyelectrolytes. For high salt concentration we find that the critical adsorption concentration (CAC) is a bilinear function of the polyion monomer and salt concentrations, with the coefficients dependent only on the type of surfactant used. The results presented in the paper might be useful for designing more efficient gene delivery systems.

Source: http://arxiv.org/abs/0709.4490v1

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Sep 19, 2013
09/13

by
Yan Levin; Alexandre P. dos Santos; Alexandre Diehl

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Availability of highly reactive halogen ions at the surface of aerosols has tremendous implications for the atmospheric chemistry. Yet neither simulations, experiments, nor existing theories are able to provide a fully consistent description of the electrolyte-air interface. In this paper a new theory is proposed which allows us to explicitly calculate the ionic density profiles, the surface tension, and the electrostatic potential difference across the solution-air interface. Predictions of...

Source: http://arxiv.org/abs/0909.2222v2

3
3.0

Jun 29, 2018
06/18

by
Thiago Colla; Matheus Girotto; Alexandre P. dos Santos; Yan Levin

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We study, using Density Functional theory and Monte Carlo simulations, aqueous electrolyte solutions between charged infinite planar surfaces, in a contact with a bulk salt reservoir. In agreement with recent experimental observations [Z. Luo et al., Nat. Comm. 6, 6358 (2015)], we find that the confined electrolyte lacks local charge neutrality. We show that a Density Functional Theory (DFT) based on a bulk- HNC expansion properly accounts for strong electrostatic correlations and allows us to...

Topics: Soft Condensed Matter, Condensed Matter

Source: http://arxiv.org/abs/1609.00619

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Sep 22, 2013
09/13

by
Alexandre Diehl; Humberto A. Carmona; Yan Levin

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A simple model is presented for the appearance of attraction between two like charged polyions inside a polyelectrolyte solution. The polyions are modeled as rigid cylinders in a continuum dielectric solvent. The strong electrostatic interactions between the polyions and the counterions results in counterion condensation. If the two polyions are sufficiently close to each other their layers of condensed counterions can become correlated resulting in attraction between the macromolecules. To...

Source: http://arxiv.org/abs/cond-mat/0011308v1

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48

Sep 20, 2013
09/13

by
M. N. Tamashiro; Yan Levin; Marcia C. Barbosa

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The one-component plasma (OCP) represents the simplest statistical mechanical model of a Coulomb system. For this reason, it has been extensively studied over the last forty years. The advent of the integral equations has resulted in a dramatic improvement in our ability to carry out numerical calculations, but came at the expense of a physical insight gained in a simpler analytic theory. In this paper we present an extension of the Debye-Hueckel (DH) theory to the OCP. The theory allows for...

Source: http://arxiv.org/abs/cond-mat/9810213v2

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4.0

Jun 30, 2018
06/18

by
Fernanda P. C. Benetti; Ana C. Ribeiro-Teixeira; Renato Pakter; Yan Levin

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Three dimensional self-gravitating systems do not evolve to thermodynamic equilibrium, but become trapped in nonequilibrium quasistationary states. In this Letter we present a theory which allows us to a priori predict the particle distribution in a final quasistationary state to which a self-gravitating system will evolve from an initial condition which is isotropic in particle velocities and satisfies a virial constraint 2K=-U, where K is the total kinetic energy and U is the potential energy...

Topics: Astrophysics of Galaxies, Astrophysics, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1409.2060

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37

Sep 21, 2013
09/13

by
Thiago E. Colla; Yan Levin

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An extension of the renormalized Jellium model which allows to study colloidal suspensions containing trivalent counterions is proposed. The theory is based on a modified Poisson-Boltzmann equation which incorporates the effects of counterion correlations near the colloidal surfaces using a new boundary condition. The renormalized charges, the counterion density profiles, and osmotic pressures can be easily calculated using the modified renormalized Jellium model. The results are compared with...

Source: http://arxiv.org/abs/1011.2725v1

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Sep 22, 2013
09/13

by
Tarcísio N. Teles; Yan Levin; Renato Pakter; Felipe B. Rizzato

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We study, using both theory and molecular dynamics simulations, the relaxation dynamics of a microcanonical two dimensional self-gravitating system. After a sufficiently large time, a gravitational cluster of N particles relaxes to the Maxwell-Boltzmann distribution. The time to reach the thermodynamic equilibrium, however, scales with the number of particles. In the thermodynamic limit, $N\to\infty$ at fixed total mass, equilibrium state is never reached and the system becomes trapped in a...

Source: http://arxiv.org/abs/1004.0247v2

3
3.0

Jun 30, 2018
06/18

by
Thiago Colla; Christos N. Likos; Yan Levin

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The equilibrium properties of ionic microgels are investigated using a combination of the Poisson-Boltzmann and Flory theories. Swelling behavior, density profiles, and effective charges are all calculated in a self-consistent way. Special attention is given to the effects of salinity on these quantities. It is found that the equilibrium microgel size is strongly influenced by the amount of added salt. Increasing the salt concentration leads to a considerable reduction of the microgel volume,...

Topics: Soft Condensed Matter, Condensed Matter

Source: http://arxiv.org/abs/1406.4302

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38

Jul 20, 2013
07/13

by
Yan Levin

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A model of a finite cylindrical ion channel through a phospholipid membrane of width $L$ separating two electrolyte reservoirs is studied. Analytical solution of the Poisson equation is obtained for an arbitrary distribution of ions inside the trans-membrane pore. The solution is asymptotically exact in the limit of large ionic strength of electrolyte on the two sides of membrane. However, even for physiological concentrations of electrolyte, the electrostatic barrier sizes found using the...

Source: http://arxiv.org/abs/cond-mat/0604099v2

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44

Sep 19, 2013
09/13

by
Tarcísio Nunes Teles; Renato Pakter; Yan Levin

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We present a theory that allows us to accurately calculate the distribution functions and the emittance growth of a thermal charged-particle beam after it relaxes to equilibrium. The theory can be used to obtain the fraction of particles, which will evaporate from the beam to form a halo. The calculated emittance growth is found to be in excellent agreement with the simulations.

Source: http://arxiv.org/abs/0910.5234v1

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Sep 23, 2013
09/13

by
Fernanda P. da C. Benetti; Tarcísio N. Teles; Renato Pakter; Yan Levin

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We explore the mechanism responsible for the ergodicity breaking in systems with long-range forces. In thermodynamic limit such systems do not evolve to the Boltzmann-Gibbs equilibrium, but become trapped in an out-of-equilibrium quasi-stationary-state. Nevertheless, we show that if the initial distribution satisfies a specific constraint - a generalized virial condition - the quasi- stationary-state is very close to ergodic and can be described by Lynden-Bell statistics. On the other hand if...

Source: http://arxiv.org/abs/1202.1810v2

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Sep 18, 2013
09/13

by
S. Pianegonda; Marcia C. Barbosa; Yan Levin

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A theory is presented for the effective charge of colloidal particles in suspensions containing multivalent counterions. It is shown that if colloids are sufficiently strongly charged, the number of condensed multivalent counterion can exceed the bare colloidal charge leading to charge reversal. Charge renormalization in suspensions with multivalent counterions depends on a subtle interplay between the solvation energies of the multivalent counterions in the bulk and near the colloidal surface....

Source: http://arxiv.org/abs/cond-mat/0509604v1

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Sep 22, 2013
09/13

by
Yan Levin

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In this brief review I will discuss criticality in strongly correlated fluids. Unlike simple fluids, molecules of which interact through short ranged isotropic potential, particles of strongly correlated fluids usually interact through long ranged forces of Coulomb or dipolar form. While for simple fluids mechanism of phase separation into liquid and gas was elucidated by van der Waals more than a century ago, the universality class of strongly correlated fluids, or in some cases even existence...

Source: http://arxiv.org/abs/cond-mat/0111247v1

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Sep 24, 2013
09/13

by
Juergen F. Stilck; Yan Levin; Jeferson J. Arenzon

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We study the thermodynamic properties of a simple model for the possible mechanism of attraction between like charged rodlike polyions inside a polyelectrolyte solution. We consider two polyions in parallel planes, with $Z$ charges each, in a solution containing multivalent counterions of valence $\alpha$. The model is solved exactly for $Z \le 13$ for a general angle $\theta$ between the rods and supposing that $n$ counterions are condensed on each polyion. The free energy has two minima, one...

Source: http://arxiv.org/abs/cond-mat/0103590v1

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Jul 22, 2013
07/13

by
Alexandre Diehl; Marcia C. Barbosa; Yan Levin

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Sine-Gordon field theory is used to investigate the phase diagram of a neutral Coulomb gas. A variational mean field free energy is constructed and the corresponding phase diagrams in two (2d) and three dimensions (3d) are obtained. When analyzed in terms of chemical potential, the Sine-Gordon theory predicts the phase diagram topologically identical with the Monte Carlo simulations and a recently developed Debye-H\"uckel-Bjerrum (DHBj) theory. In 2d we find that the infinite order...

Source: http://arxiv.org/abs/cond-mat/9702140v1

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Sep 23, 2013
09/13

by
Emmanuel Trizac; Yan Levin

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We introduce a renormalized Jellium model to calculate the equation of state for charged colloidal suspensions. An almost perfect agreement with Monte Carlo simulations is found. Our self-consistent approach naturally allows to define the effective charge of particles {\em at finite colloidal density}. Although this quantity may differ significantly from its counterpart obtained from the standard Poisson-Boltzmann cell approach, the osmotic pressures for both models are in good agreement. We...

Source: http://arxiv.org/abs/cond-mat/0312423v1

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48

Sep 20, 2013
09/13

by
Yan Levin

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We study the interaction potential between two polyions inside a colloidal suspension. It is shown that at large separation the interaction potential is purely repulsive, with the induced attractive interactions being doubly screened. For short separations the condensed counterions become correlated, what leads to an effective attraction between the two macromolecules.

Source: http://arxiv.org/abs/cond-mat/9802153v1

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Sep 20, 2013
09/13

by
Yan Levin

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A comparison between the Kosterlitz-Thouless theory of metal insulator transition in a two dimensional plasma and a counterion condensation in a polyelectrolyte solution is made. It is demonstrated that, unlike some of the recent suggestions, the counterion condensation and the Kosterlitz-Thouless transition are distinct.

Source: http://arxiv.org/abs/cond-mat/9802154v1

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Sep 20, 2013
09/13

by
Heitor C. Marques Fernandes; Yan Levin; Jeferson J. Arenzon

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A simple equation of state for a lattice gas of hard squares of side length $\lambda$ is presented. Comparing to the Monte Carlo simulations, the new equation of state is found to be quite accurate for the disordered fluid phase.

Source: http://arxiv.org/abs/cond-mat/0608220v1

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Sep 20, 2013
09/13

by
M. N. Tamashiro; Yan Levin; Marcia C. Barbosa

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We consider a system composed of a monodisperse charge-stabilized colloidal suspension in the presence of monovalent salt, separated from the pure electrolyte by a semipermeable membrane, which allows the crossing of solvent, counterions, and salt particles, but prevents the passage of polyions. The colloidal suspension, that is in a crystalline phase, is considered using a spherical Wigner-Seitz cell. After the Donnan equilibrium is achieved, there will be a difference in pressure between the...

Source: http://arxiv.org/abs/cond-mat/9802137v1

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Sep 19, 2013
09/13

by
Salete Pianegonda; Emmanuel Trizac; Yan Levin

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Starting from a mean-field description for a dispersion of highly charged spherical or (parallel) rod-like colloids, we introduce the simplification of a homogeneous background to include the contribution of other polyions to the static field created by a tagged polyion. The charge of this background is self-consistently renormalized to coincide with the polyion effective charge, the latter quantity thereby exhibiting a non-trivial density dependence, which directly enters into the equation of...

Source: http://arxiv.org/abs/cond-mat/0701048v1

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Sep 19, 2013
09/13

by
Alexandre Diehl; Marcia C. Barbosa; Yan Levin

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We explore the effects of counterion condensation on fluid-fluid phase separation in charged colloidal suspensions. It is found that formation of double layers around the colloidal particles stabilizes suspensions against phase separation. Addition of salt, however, produces an instability which, in principle, can lead to a fluid-fluid separation. The instability, however, is so weak that it should be impossible to observe a fully equilibrated coexistence experimentally.

Source: http://arxiv.org/abs/cond-mat/0010352v1

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Sep 23, 2013
09/13

by
Felipe B. Rizzato; Renato Pakter; Yan Levin

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A statistical theory is presented which allows to calculate the stationary state achieved by a driven system after a process of collisionless relaxation. The theory is applied to study an electron beam driven by an external electric field. The Vlasov equation with appropriate boundary conditions is solved analytically and compared with the molecular dynamics simulation. A perfect agreement is found between the theory and the simulations. The full current-voltage phase diagram is constructed.

Source: http://arxiv.org/abs/0904.0259v1

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Sep 20, 2013
09/13

by
Jeferson J. Arenzon; Yan Levin; Mauro Sellitto

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We present an analytical and numerical study of a nonlinear diffusion model which describes density relaxation of loosely packed particles under gravity and weak random (thermal) vibration, and compare the results with Monte Carlo simulations of a lattice gas under gravity. The dynamical equation can be thought of as a local density functional theory for a class of lattice gases used to model slow relaxation of glassy and granular materials. The theory predicts a jamming transition line between...

Source: http://arxiv.org/abs/cond-mat/0301454v1

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Sep 23, 2013
09/13

by
Alexandre Diehl; Yan Levin

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Extensive Monte Carlo simulations and scaling arguments are used to study the colloidal charge reversal. The critical colloidal surface charge density $\sigma_c$ at which the reversal first appears is found to depend strongly on the ionic size. We find that $\sigma_c$ has an inflection point as a function of the electrolyte concentration. The width of the plateau region in the vicinity of the inflection point depends on the temperature and the ionic radius $a$. In agreement with the theoretical...

Source: http://arxiv.org/abs/0810.0510v1

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Sep 21, 2013
09/13

by
Yan Levin

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In a recent PRL Barci and Stariolo (BS) generalized the well known Brazovskii model to include an additional rotationally invariant quartic interaction and study this model in two dimensions (2d). Depending on the parameters of the model, BS find two transitions: a first order isotropic-lamellar (striped) or a second order isotropic-nematic (which they speculate to be in the Kosterlitz-Thouless universality class). Using a simple symmetry argument, I show that the striped phase found by BS can...

Source: http://arxiv.org/abs/0709.4205v2

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Sep 22, 2013
09/13

by
Yan Levin; Fernando L. da Silveira; Felipe B. Rizzato

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A calculation is presented which quantitatively accounts for the terminal velocity of a cylindrical magnet falling through a long copper or aluminum pipe. The experiment and the theory are a dramatic illustration of the Faraday's and Lenz's laws and are bound to capture student's attention in any electricity and magnetism course.

Source: http://arxiv.org/abs/physics/0603270v2

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Sep 18, 2013
09/13

by
Tarcísio N. Teles; Fernanda Benetti; Renato Pakter; Yan Levin

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We introduce a generalized Hamiltonian Mean Field Model (gHMF)-XY model with both linear and quadratic coupling between spins and explicit Hamiltonian dynamics. In addition to the usual paramagnetic and ferromagnetic phases, this model also possesses a nematic phase. The gHMF can be solved explicitly using Boltzmann-Gibbs (BG) statistical mechanics, in both canonical and microcanonical ensembles. However, when the resulting microcanonical phase diagram is compared with the one obtained using...

Source: http://arxiv.org/abs/1211.1522v2

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Sep 21, 2013
09/13

by
Yan Levin; Jeferson J. Arenzon; Jurgen F. Stilck

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Comment on the paper of Ha and Liu (Phys. Rev. Lett. {\bf 79}, 1289 (1997)) regarding the nature of attraction between like charged rods. We demostrate that their results do not produce the correct low temperature limit.

Source: http://arxiv.org/abs/cond-mat/9907428v1

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Sep 22, 2013
09/13

by
Alexandre P. dos Santos; Yan Levin

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We study the ionic distribution near a charged surface. A new method for performing Monte Carlo simulations in this geometry is discussed. A theory is then presented that allows us to accurately reproduce the density profiles obtained in the simulations. In the weak-coupling regime, a theory accounts for the ion-image interactions, leading to a modified Poisson-Boltzmann equation. When the correlations between the ions are significant, a strong-coupling theory is used to calculate the density...

Source: http://arxiv.org/abs/1210.8381v2

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Sep 23, 2013
09/13

by
A. Diehl; M. N. Tamashiro; Marcia C. Barbosa; Yan Levin

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We study the interactions between two negatively charged macroscopic surfaces confining positive counterions. A density-functional approach is introduced which, besides the usual mean-field interactions, takes into account the correlations in the positions of counterions. The excess free energy is derived in the framework of the Debye-H{\"u}ckel theory of the one-component plasma, with the homogeneous density replaced by a weighted density. The minimization of the total free energy yields...

Source: http://arxiv.org/abs/cond-mat/9904114v1

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Sep 23, 2013
09/13

by
Yan Levin; Renato Pakter

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In their Reply [arXiv:1104.5036] to our Comment [arXiv:1104.0697] Andrade et al. state that we have "chosen to categorically dismiss their elaborate and solid conceptual approach without employing any concepts or tools from Statistical Mechanics". Because of the one page restriction imposed by PRL, we could not address all of the flaws of the original paper. Therefore, we are grateful to Andrade et al., for giving us an opportunity to further elaborate on our Comment. In this...

Source: http://arxiv.org/abs/1105.1316v1

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Sep 23, 2013
09/13

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Tarcísio Nunes Teles; Yan Levin; Renato Pakter

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We study, using both theory and simulations, a system of self-gravitating sheets. A new statistical mechanics theory - free of any adjustable parameters - is derived to quantitatively predict the final stationary state achieved by this system after the process of collisionless relaxation is completed. The theory shows a very good agreement with the numerical simulations. The model sheds new light on the general mechanism of relaxation of self-gravitating systems and may help us to understand...

Source: http://arxiv.org/abs/1109.3780v1

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Sep 20, 2013
09/13

by
Heitor C. Marques Fernandes; Jeferson J. Arenzon; Yan Levin

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Monte Carlo simulations are used to study lattice gases of particles with extended hard cores on a two dimensional square lattice. Exclusions of one and up to five nearest neighbors (NN) are considered. These can be mapped onto hard squares of varying side length, $\lambda$ (in lattice units), tilted by some angle with respect to the original lattice. In agreement with earlier studies, the 1NN exclusion undergoes a continuous order-disorder transition in the Ising universality class....

Source: http://arxiv.org/abs/cond-mat/0612372v1

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Sep 21, 2013
09/13

by
Yan Levin; Marco A. Idiart

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We present a theory for pore dynamics of osmotically stressed vesicles. When a liposome with an internal concentration of solute is placed inside a solute-depleted medium, an osmotic flow of solvent through the lipid bilayer leads to swelling of vesicle and to increase in membrane surface tension. This can result in membrane rupture and opening of thermal pores. Depending on the internal concentration of solute and the size of the vesicle, pores can close rapidly or be long-lived. We find that...

Source: http://arxiv.org/abs/cond-mat/0311350v1