When a system is driven across a second-order quantum phase transition, the number of defects which are produced scales with the speed of the variation of the tuning parameter according to a universal law described by the Kibble-Zurek mechanism. We study a possible breakdown of this prediction proving that the number of defects can exhibit another universal scaling law which is still related only to the critical exponents $z$ and $\nu$, but differs from the Kibble-Zurek result. Finally we provide an example, the deformed Fredkin spin chain, where this violation of the standard adiabatic dynamics can occur.
Categories: cond-mat.stat-mech quant-ph