Nonextensive Statistical Mechanics

80 3 Generalizing What We Learnt0.080.082q ent0.080.060.078q ent λ0.998 1 1.0020.0410.02r0.99999995(λ = 1, γ = 1)0.0824 0.0828 0.0832q00.85 0.9 0.95 1 1.05 1.1 1.15λFig. 3.17 The λ-dependence of the index q ent in the Ising (γ = 1, circle) and XY (γ = 0.75,square) chains. At bottom: Determination of q ent through numerical maximization of the linearcorrelation coefficient r of S q (ˆρ L ). The error bars for the Ising chain are obtained considering thevariation of q ent when using the range 100 ≤ L ≤ 400 in the search of S q (ˆρ L ) linear behavior.Actually, at the present numerical level, we cannot exclude finite-size effects of criticality.2000020150001510s qents qent0.98 0.99 1 1.01 1.0210000505000λ00.85 0.9 0.95 1 1.05 1.1 1.15Fig. 3.18 The λ-dependence of the q-entropic density s qent in the Ising (γ = 1, circle) and XY(γ = 0.75, square) models. For λ = 1, the slopes are (3.56) and (2.63), for γ = 1andγ = 0.75,respectively.λ