Coherent quantum control in biological systems

Abstract

Coherent quantum control has recently induced a revolution in photochemistry. Not only can the atomic motion be observed within molecules by snapshots of a few femtoseconds duration, it can now also be controlled. The basic idea of this revolution is the use of quantum interference between different states that are in coherent superposition so that a target state is reached with maximum probability. The mechanism reminds interference in optics, where some optical paths are favored (constructive interference) while others are discarded (destructive interference), as in Young's double slit experiment. A key element for achieving this control is the transfer of coherence from the exciting light field to the atomic or molecular system via the electric dipole operator. A tailored coherent laser pulse is used to excite a molecule in a superposition of states, which drives the molecule along a specific path to obtain a targeted result. © 2011 Springer Science+Business Media B.V.