Observation of Quantum Interference and Coherent Control in a Photochemical Reaction

Abstract

Coherent control of reactants remains a longstanding challenge in quantum chemistry. In particular, we have studied laser-induced molecular formation (photoassociation) in a Raman-dressed spin-orbit-coupled 87Rb Bose-Einstein condensate, whose spin quantum state is a superposition of multiple bare spin components. In contrast to the notably different photoassociation-induced fractional atom losses observed for the bare spin components of a statistical mixture, a superposition state with a comparable spin composition displays the same fractional loss on every spin component. We interpret this as the superposition state itself undergoing photoassociation. For superposition states induced by a large Raman coupling and zero Raman detuning, we observe a nearly complete suppression of the photoassociation rate. This suppression is consistent with a model based upon quantum destructive interference between two photoassociation pathways for colliding atoms with different spin combinations. This model also explains the measured dependence of the photoassociation rate on the Raman detuning at a moderate Raman coupling. Our work thus suggests that preparing atoms in quantum superpositions may represent a powerful new technique to coherently control photochemical reactions.

References in corpus (16)

• A spin-orbit coupled Bose-Einstein condensate
• Tuning the scattering length with an optically induced Feshbach resonance
• A Bose-Einstein Condensate in a Uniform Light-induced Vector Potential
• Tunable Landau-Zener transitions in a spin-orbit coupled Bose-Einstein condensate
• Photoassociation of sodium in a Bose-Einstein condensate
• A Raman-induced Feshbach resonance in an effectively single-component Fermi gas
• Synthetic partial waves in ultracold atomic collisions
• Spin-Orbit Coupling Induced Coherent Production of Feshbach Molecules in a Degenerate Fermi Gas
• Coherent Control of Bond Making
• Photoassociation spectroscopy of a Spin-1 Bose-Einstein condensate
• Optimizing the efficiency of evaporative cooling in optical dipole traps
• Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond Frequency Chirps
• Efficient Formation of Ultracold Molecules with Chirped Nanosecond Pulses
• Ultracold Molecule Assembly with Photonic Crystals
• Stueckelberg interferometry using periodically driven spin-orbit coupled Bose-Einstein condensates
• Directional Quantum-Controlled Chemistry: Generating Aligned Ultracold Molecules via Photoassociation

Cited by in corpus (6)

• Spin-momentum entanglement in a Bose-Einstein condensate
• Effect of spin-orbit coupling on tunnelling escape of Bose-Einstein condensate
• Statistical correlation between quantum entanglement and spin-orbit coupling in crossed beam molecular dynamics
• Quasi-two-dimensional soliton in a self-repulsive spin-orbit-coupled dipolar binary condensate
• Weak-Field Coherent Control of Ultrafast Molecule Making
• Coherent Control of Ultrafast Bond Making and Subsequent Molecular Dynamics: Demonstration of Final-State Branching Ratio Control