Experimental measurement of the persistence exponent of the planar Ising model

Using a twisted nematic liquid crystal system exhibiting planar Ising model dynamics, we have measured the scaling exponent θ, which characterizes the time evolution $p\left(t\right)\mathrm{}\sim t^{-\theta },$ of the probability $p\left(t\right)\mathrm{}$ that the local order parameter has not switched its state by the time $t.\mathrm{}$ For 0.4 sec–200 sec following the phase quench, the system exhibits scaling behavior and, measured over this interval, θ=0.19±0.03, in good agreement with theoretical analysis and numerical simulations