Quantum dynamics experienced by a single molecular eigenstate excited by incoherent light.

Area of Science:

• Quantum Dynamics
• Molecular Physics
• Spectroscopy

Background:

• Conventional understanding attributes molecular dynamics to interference between multiple energy eigenstates.
• The presence of continua of states in molecular systems is common, arising from interactions with the environment (bath modes, photon emission, electron detachment, bond dissociation).
• Single bound energy eigenstates are real functions, exhibiting no flux or dynamics.

Purpose of the Study:

• To demonstrate that single molecular eigenstates can undergo steady-state quantum dynamics.
• To show that this dynamics can be initiated by incoherent light sources.
• To elucidate the mechanism and control of this novel quantum dynamics.

Main Methods:

• Theoretical analysis of quantum mechanical principles.
• Examination of complex continuum energy eigenfunctions.
• Investigation of multimode resonances embedded within continua.

Main Results:

• A single complex continuum energy eigenfunction exhibits steady-state flux, determined by its group velocity.
• This flux represents a form of quantum dynamics not dependent on interference between multiple eigenstates.
• Multimode resonances within a continuum, coupled intramolecularly, can initiate and sustain this steady-state dynamics.
• The dynamics are controllable by the resonance position, not its width, offering a new paradigm compared to coherent wave packet dynamics.

Conclusions:

• Steady-state quantum dynamics can occur in single molecular eigenstates when embedded in a continuum.
• Incoherent light sources can initiate these dynamics.
• This finding challenges the conventional view and opens new avenues for controlling molecular behavior using light.