Coherence in the Control of Molecular Processes

Fabien Gatti, Benjamin Lasorne, Hans‐Dieter Meyer +1 more

龚尚庆, 钮月萍, 宋晓红 +3 more

Several schemes for coherent quantum control of atomic and molecular processes have been proposed and investigated by using the techniques of adiabatic passage and ultrashort pulses, respectively. Some interesting results have been found.

Moshe Shapiro, Paul W. Brumer

We review the principles and some recent advances in the theory of coherent control of molecular processes and discuss some of its experimental realizations. Amongst the topics discussed are: bichromatic and pump-dump control; the interference between N-photons and M-photon processes; the optical conversion of a mixture of left- and right-handed chiral molecules into an ensemble containing molecules of the handedness of choice; control of collisional processes; control over chaotic dynamics; effects of decoherence; the solution of the non-degenerate quantum control problem; and control over spontaneous emission and other decay processes.

Paul W. Brumer, Moshe Shapiro

Viswanath Ramakrishna

Jiangbin Gong, Paul W. Brumer

The subtle and fundamental issue of indistinguishability and interference between independent pathways to the same target state is examined in the context of coherent control of atomic and molecular processes, with emphasis placed on possible "which-way" information due to quantum entanglement established in the quantum dynamics. Because quantum interference between independent pathways to the same target state occurs only when the independent pathways are indistinguishable, it is first shown that creating useful coherence between nondegenerate states of a molecule for subsequent quantum interference manipulation cannot be achieved by collisions between atoms or molecules that are prepared in momentum and energy eigenstates. Coherence can, however, be transferred from light fields to atoms or molecules. Using a particular coherent control scenario, it is shown that this coherence transfer and the subsequent coherent phase control can be readily realized by the most classical states of light, i.e., coherent states of light. It is further demonstrated that quantum states of light may suppress the extent of phase-sensitive coherent control by leaking out some which-way information while "incoherent interference control" scenarios proposed in the literature have automatically ensured the indistinguishability of multiple excitation pathways. The possibility of quantum coherence in photodissociation product states is also understood in terms of the disentanglement between photodissociation fragments. Results offer deeper insights into quantum coherence generation in atomic and molecular processes.