Proposed fitting function for the critical Casimir force on < sup > 4 < /sup > He film below the λ point

Abstract

We have extended the mean field calculations [9] of Zandi et al. (2007) and have obtained an approximate mathematical expression for the Casimir scaling function θ{symbol} (y), which if extrapolated to the domain π2 ≥ - y ≥ 0, becomes surprisingly similar to that obtained experimentally [16] by Ganshin et al. (2006). The extrapolated θ{symbol} (y) can be regarded as a proposed fitting function, that appears to agree better with the experiments [16] in D = 3, than the exact mean field results of Zandi et al. (2007) [9]. © 2010 Elsevier B.V. All rights reserved.