MICROCANONICAL SIMULATIONS OF ELASTIC-DISK SYSTEMS

1994 ◽  
Vol 05 (06) ◽  
pp. 1021-1034 ◽  
Author(s):  
WOLFGANG VERMÖHLEN ◽  
NOBUYASU ITO

We performed MD-simulation of two dimensional elastic disks in a microcanonical ensemble and observed the pressure versus the density for the different elastic moduli. As was found in Alder’s simulation, we reconfirmed a plateau in the (pred, ρ*) diagram as an indication for a phase transition with better statistics and observed its dependence on the elastic modulus. This dependence can be explained by the effective density reduction due to the elasticity of the disks. This suggests the universality of the Alder transition of the hard core potential for the contacting elastic potentials. A discussion of a geometrical order parameter |ɸ|2 is included.

2020 ◽  
Vol 62 (4) ◽  
pp. 610
Author(s):  
А.А. Берзин ◽  
А.И. Морозов ◽  
А.С. Сигов

The phase diagram of two-dimensional systems with continuous symmetry of the vector order parameter containing defects of the “random local anisotropy” type is investigated. In the case of a weakly anisotropic distribution of the easy anisotropy axes in the space of the order parameter, with decreasing temperature, a smooth transition takes place from the paramagnetic phase with dynamic fluctuations of the order parameter to the Imri-Ma phase with its static fluctuations. In the case when the anisotropic distribution of the easy axes induces a global anisotropy of the “easy axis” type that exceeds a critical value, the system goes into the Ising class of universality, and a phase transition to the ordered state occurs in it at a finite temperature.


2020 ◽  
Vol 62 (2) ◽  
pp. 281
Author(s):  
А.А. Берзин ◽  
А.И. Морозов ◽  
А.С. Сигов

A.A. Berzin, A.I. Morosov, and A.S. Sigov The influence of defects of the “random local field” type with an anisotropic distribution of random fields on two-dimensional models with continuous symmetry of the vector order parameter is considered. In the case of weak anisotropy of random fields, with decreasing temperature there takes place a smooth transition from the paramagnetic phase with dynamic fluctuations of the order parameter to the Imry-Ma phase with static fluctuations caused by fluctuations of the random field of defects. In the case of strong anisotropy of random fields, defects lead to an effective decrease in the number of components of the order parameter and the appearance of a phase transition to an ordered state at finite temperature.


2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.


2000 ◽  
Vol 61 (17) ◽  
pp. 11289-11292 ◽  
Author(s):  
Alessandro Cuccoli ◽  
Andrea Fubini ◽  
Valerio Tognetti ◽  
Ruggero Vaia

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