title: Adiabatic dynamics in passage across quantum critical lines and gapless phases.
abstract: It is well known that the dynamics of a quantum system is always nonadiabatic in passage through a quantum critical point and the defect density in the final state following a quench shows a power-law scaling with the rate of quenching. However, we propose here a possible situation where the dynamics of a quantum system in passage across quantum critical regions is adiabatic and the defect density decays exponentially. This is achieved by incorporating additional interactions which lead to quantum critical behavior and gapless phases but do not participate in the time evolution of the system. To illustrate the general argument, we study the defect generation in the quantum critical dynamics of a spin-1/2 anisotropic quantum XY spin chain with three spin interactions and a linearly driven staggered magnetic field.
authors.affiliation: Department of Physics, Indian Institute of Technology, Kanpur 208 016, India. debanjanchowdhury@gmail.com
authors.forename: Debanjan
authors.initials: D
authors.lastname: Chowdhury
authors.forename: Uma
authors.initials: U
authors.lastname: Divakaran
authors.forename: Amit
authors.initials: A
authors.lastname: Dutta