Indistinguishability and interference in the coherent control of atomic and molecular processes

Journal Article · Sun Feb 07 00:00:00 EST 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3304921· OSTI ID:21559831

Jiangbin, Gong ^[1]; Brumer, Paul ^[2]

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1. Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore) and NUS Graduate School for Integrative Sciences and Engineering, Singapore 117597 (Singapore)
2. Department of Chemistry and Center for Quantum Information and Quantum Control, Chemical Physics Theory Group, University of Toronto, Toronto M5S 3H6 (Canada)

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.

• OSTI ID: 21559831
• Journal Information: Journal of Chemical Physics, Vol. 132, Issue 5; Other Information: DOI: 10.1063/1.3304921; (c) 2010 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANNIHILATION OPERATORS
ATOMS
CONTROL
DISSOCIATION
EIGENSTATES
EXCITATION
INTERFERENCE
MOLECULES
OPTICS
PHOTOLYSIS
PHOTON-ATOM COLLISIONS
QUANTUM ENTANGLEMENT
QUANTUM STATES
VISIBLE RADIATION
ATOM COLLISIONS
CHEMICAL REACTIONS
COLLISIONS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
MATHEMATICAL OPERATORS
PHOTOCHEMICAL REACTIONS
PHOTON COLLISIONS
QUANTUM OPERATORS
RADIATIONS