Excitation of large-scale delocalized quantum state by local interactions

¹ Applied Ion Beam Physics Laboratory, Institute of Modern Physics, Department of Nuclear Science and Technology, Fudan University - Shanghai 200433, China
² Department of Optical Science and Engineering, Fudan University - Shanghai 200433, China

^a xjning@fudan.edu.cn

Received: 25 June 2010
Accepted: 21 September 2010

Abstract

It seems impossible to establish the population Rabi oscillation between two delocalized states by a resonant electromagnetic wave beam focused in a local area because the interaction information would be simultaneously propagated to every spatial point of the system, breaking relativistic causality. We examined this issue in an ideal model of a single electron moving in a one-dimensional box and in a realistic system of a monatomic carbon chain, showing that the resonant Rabi oscillation cannot be established until the initial wave package, formed by many other far-off-resonant states, transports from the interaction area crossing over all the system space. Furthermore, it is demonstrated that the two-level approximation is good when the duration of laser pumping is long enough, and if the laser interaction area is shorter than 10% of the system size, it is very difficult to pump the population of the ground state to excited ones at finite temperatures.