A mean-field model of the alkane-saturated lipid bilayer above its phase transition. II. Results and comparison with experiment

This work presents our investigations of mezomorphic properties of two polymorphic liquid crystals, namely, 4-nonyloxy-4-butoxyphenyl benzoate and N-(-4-heptyloxybenzylidene-4-butylaniline) in a wide temperature range, particularly, in the phase transition regions. By means of an original experimental method, the heterophase regions and also the phase transition temperatures have been determined for these materials with high accuracy. These phase transition intervals have been analyzed using a mean field model.

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Calculation of the tilt angle and susceptibility for the α–β transition in quartz using a mean field model

Modern Physics Letters B ◽

10.1142/s0217984917500920 ◽

2017 ◽

Vol 31 (09) ◽

pp. 1750092 ◽

Cited By ~ 2

Author(s):

H. Yurtseven ◽

U. Ipekoğlu ◽

S. Ateş

Keyword(s):

Experimental Data ◽

Phase Transition ◽

Temperature Dependence ◽

Tilt Angle ◽

Phenomenological Model ◽

Order Parameter ◽

Field Model ◽

Mean Field ◽

Mean Field Model ◽

The Mean

Tilt angle (order parameter) and the susceptibility are calculated as a function of temperature for the [Formula: see text]–[Formula: see text] transition in quartz using a Landau phenomenological model. The tilt angle as obtained from the model is fitted to the experimental data from the literature and the temperature dependence of the tilt angle susceptibility is predicted close to the [Formula: see text]–[Formula: see text] transition in quartz. Our results show that the mean field model explains the observed behavior of the [Formula: see text]–[Formula: see text] phase transition in quartz adequately and it can be applied to some related materials.

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Phase transitions of quasistationary states in the Hamiltonian Mean Field model

Open Physics ◽

10.2478/s11534-012-0010-6 ◽

2012 ◽

Vol 10 (3) ◽

Cited By ~ 2

Author(s):

Pierre Buyl ◽

Duccio Fanelli ◽

Stefano Ruffo

Keyword(s):

Phase Transition ◽

Order Parameter ◽

Field Model ◽

Equilibrium Phase ◽

Mean Field ◽

Correct Order ◽

Mean Field Model ◽

Equilibrium Dynamics ◽

Equilibrium Phase Transition ◽

Negative Susceptibility

AbstractThe out-of equilibrium dynamics of the Hamiltonian Mean Field (HMF) model is studied in presence of an externally imposed magnetic field h. Lynden-Bell’s theory of violent relaxation is revisited and shown to adequately capture the system dynamics, as revealed by direct Vlasov based numerical simulations in the limit of vanishing field. This includes the existence of an out-of-equilibrium phase transition separating magnetized and non magnetized phases. We also monitor the fluctuations in time of the magnetization, which allows us to elaborate on the choice of the correct order parameter when challenging the performance of Lynden-Bell’s theory. The presence of the field h removes the phase transition, as it happens at equilibrium. Moreover, regions with negative susceptibility are numerically found to occur, in agreement with the predictions of the theory.

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