The isotropic-to-nematic transition in a two-dimensional fluid of hard needles : a finite-size scaling study

Abstract

The isotropic-to-nematic transition in a two-dimensional fluid of hard needles is studied using grand canonical Monte Carlo simulations, multiple histogram reweighting, and finite size scaling. The transition is shown to be of the Kosterlitz-Thouless type, via a direct measurement of the critical exponents eta and beta, of the susceptibility and order parameter, respectively. At the transition, eta=1/4 and beta=1/8 are observed, in excellent agreement with Kosterlitz-Thouless theory. Also the shift in the chemical potential of the nematic susceptibility maximum with system size is in good agreement with theoretical expectations. Some evidence of singular behavior in the density fluctuations is observed, but no divergence, consistent with a negative specific heat critical exponent. At the transition, a scaling analysis assuming a conventional critical point also gives reasonable results. However, the apparent critical exponent beta_eff obtained in this case is not consistent with theoretical predictions.

7 pages, 13 figures. To appear in the European Physical Journal B (EPJB)

References in corpus (2)

• Universal Window for Two Dimensional Critical Exponents
• Orientational correlations and the effect of spatial gradients in the equilibrium steady state of hard rods in 2D : A study using deposition-evaporation kinetics

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• Towards understanding the ordering behavior of hard needles: New analytical solutions in one dimension
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• Phase Boundaries of Bulk 2D Rhombi
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• Entropy of fully-packed rigid rods on generalized Husimi trees: a route to the square lattice limit