What does this equation mean?

The last major gap in this record closed two years later. Landauer’s 1961 principle had stood for half a century as a trusted but experimentally unconfirmed claim, mainly because dissipating and resolving a heat signal on the order of 10^{-21} joules from a single bit erasure was beyond available calorimetry. Antoine Bérut, Artak Arakelyan, Artyom Petrosyan, Sergio Ciliberto, Raoul Dillenschneider, and Eric Lutz closed that gap in 2012 with “Experimental Verification of Landauer’s Principle Linking Information and Thermodynamics,” published in Nature [ 9 ] . Rather than attempting calorimetry on an electronic bit, they built a colloidal analogue: a single micron-scale bead confined in a laser-generated double-well potential, with each well standing for one logical state of a one-bit memory. By tracking the bead’s fluctuating position throughout many slow erasure cycles and computing the work done on it via the potential’s motion, they showed that the mean heat dissipated per erasure approaches — and does not fall below — $k_B$T$\ln$ 2 as the erasure is performed more slowly, exactly as Landauer’s argument predicted, and that faster erasure protocols dissipate systematically more.