Observation of Quantum Interference and Coherent Control in a Photochemical Reaction

Abstract

Coherent control of reactants remains a long-standing challenge in quantum chemistry. In particular, we have studied laser-induced molecular formation (photoassociation) in a Raman-dressed spin-orbit-coupled ^{87}Rb 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.

The diatomic molecular spectroscopy database

“…Journal of Cheminformatics *Correspondence: jperezri@fhi-berlin.mpg.de Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany chemical physics owing to their applications in quantum information [7], ultracold chemistry [8,9], and the study of physics beyond the standard model [10,11]. Most of these applications rely on laser cooling and trapping techniques, which have been achieved for a few molecules.…”

Quantum Biotechnology

“…It is now a mature field. Potential applications both in understanding chemical reactions and in biotechnology have provided the impetus for rapid experimental progress, with demonstrations of coherent control of photoexcitation [230] and photodissociation [231], of the energy transport in photosynthetic light harvesting [232], of isomeriation of retinal cells [233], of chemical bonding [234] and of photochemical reactions [235], among other processes. Several excellent reviews of coherent control already exist (e.g.…”

Numerical solution of Schrodinger equation for rotating Morse potential using matrix methods with Fourier sine basis and optimization using variational Monte‐Carlo approach

“…The study of diatomic molecules remains an important aspect of chemical physics due to its varied applications in understanding various types of chemical bonding [1], atmospheric chemistry [2] leading to astrochemistry [3]. It also provides insights into laser cooling of molecules or ultracold physics [4, 5]. Obtaining accurate potential energy function (PEF) of diatomic molecules are useful for studying chemical reactions and molecular dynamics [4].…”

“…It also provides insights into laser cooling of molecules or ultracold physics [4, 5]. Obtaining accurate potential energy function (PEF) of diatomic molecules are useful for studying chemical reactions and molecular dynamics [4]. The Morse and Lennard–Jones pair potentials are typically used in studying N‐body problems in chemical reaction theory as well as in biophysics applications such as drug design [6].…”