Ultracold molecular gases hold the promise of revolutionizing atomic, molecular, and chemical physics by enabling high-resolution quantum control of molecular interactions with external electromagnetic fields.
In the first part of this talk, I will present an efficient theoretical method for calculating low-temperature chemical reaction rates in the presence of electromagnetic fields. Using this method, I will show that electric fields with magnitudes <150 kV/cm can be used to control the total reaction cross sections, product state distributions, and the branching ratios for reactive vs inelastic scattering via electric-field-induced Feshbach resonances. In the second part of my talk, I will show how long-lived quantum coherences can be generated in multilevel atomic and molecular systems weakly illuminated by solar light. These noise-induced coherences arise due to Fano interference between incoherent pump transitions, and I will discuss the conditions under which such interference is likely to occur in real atomic and molecular systems. Finally, I will show that noise-induced coherences can play an important role in the initial stages of cis-trans photoisomerization of retinal in rhodopsin, the primary photoreaction in vision.