Spontaneous fluctuation-symmetry breaking and the Landauer principle

We will present a novel approach to the problem of the energetic cost of information erasure by looking at it through the lens of the Jarzynski equality. We will point out in what sense the Landauer principle can be distinguished from the second law of thermodynamics. The Landauer bound, $\langle W \rangle \geq kT \ln 2$, on average dissipated work $\langle W \rangle$ associated to an erasure process, literally emerges from the underlying second law bound as formulated by Kelvin, $\langle W \rangle \geq 0$, as consequence of a spontaneous breaking of the Crooks-Tasaki fluctuation-symmetry, that accompanies logical irreversibility. The latter does not generally hold true when absolute irreversibility is present, just like the Gibbs distribution becomes inappropriate for describing, e.g., ferromagnets below the critical temperature. While the second law is a direct consequence of the fluctuation relation, the Landauer principle is a direct consequence of its breakdown. We illustrate and corroborate this insight with numerical simulations of the process of information erasure performed on a 2D Ising ferromagnet.