Applying artificial neural networks to coherent control experiments: A theoretical proof of concept

Abstract

We propose a method of experimental coherent control that exploits partial and/or prior knowledge of a molecular system to efficiently arrive at a solution by using an artificial neural network (ANN) to generate a control field in consecutive temporal steps based on dynamic experimental feedback. Using a one-dimensional double-well potential model corresponding to the torsional motion of 3,5-difluoro-3 ,5-dibromobiphenyl (F 2 H 3 C 6 − C 6 H 3 Br 2) to outline and verify our approach, we theoretically demonstrate that an optimized ANN can achieve robust quantum control of nuclear wave-packet transfer between wells despite the addition of random perturbations to the simulated molecular potential energy and polarizability surfaces. We suggest that under certain conditions this will also allow the ANN to achieve the stated control objective in an experimental situation. We show that the number of measurements our method requires to generate an optimized field is equal to the dimensionality of the optimization problem, which is significantly less than a naive closed-loop approach would generally need to achieve the same results.

Torsional effects in strong-field ionization of molecules

“…II. We note that the corresponding intensities are of the same order of magnitude as those considered in very recent theoretical work on laser-induced deracemization, neglecting effects of ionization [40][41][42].…”

“…With this work we have initiated a study of torsional effects in strong-field ionization of molecules. We have investigated biphenyl and substituted biphenyl as illustrative examples motivated by the fact that torsional motion has been elucidated in alignment resolved experiments in such systems [36][37][38][39] and that these molecules have been explored theoretically in connection with laser-based protocols for laser-induced deracemization [40][41][42]. The determination of the molecular property related to the strong-field tunneling ionization process, the structure factor of the WFAT [43], was made possible by application of the newly implemented methodology [46] for the integral representation of WFAT [44] (see also Ref.…”

“…[36,37] or 3,5-difluoro-3 , 5 -dibromo-4 -cyanobiphenyl [38,39], to its mirror form by light-induced deracemization, thereby producing enantiomeric excess. More recently, the possibility for laser-induced enantiomeric conversion of DFDBrBPh based on dynamic Stark control was investigated theoretically [40,41], including considerations of possibilities associated with invoking of artificial neural networks [42]. In the latter theoretical studies, the intensities considered were up to tens of TW/cm 2 , but the role of ionization in the dynamics was not considered.…”

Torsional Wave-Packet Dynamics in 2-Fluorobiphenyl Investigated by State-Selective Ionization-Detected Impulsive Stimulated Raman Spectroscopy

“…There have been many theoretical reports considering such dynamical coupling between torsion and rotation in BP derivatives. ,,− For precisely tracking the time evolution of the system, it is required to solve four-dimensional (4D) time-dependent Schrödinger equations (TDSE) with one-dimensional (1D) + three-dimensional (3D) for vibrational and rotational degrees of freedom, respectively. − Obviously, such a full quantum calculation is too demanding, as sufficient numbers of basis functions are so large, in particular, to expand WPs for molecular rotation . Some previous studies have adopted reduced dimensional calculations, in which molecular rotation is completely ignored or regarded as a 1D motion around the major principal axis. ,,− ,− These 2D (1D torsion + 1D rotation) approaches are appropriate for molecules prealigned by adiabatic alignment, as for the time-resolved CEI experiments. − However, in usual experimental conditions, the initial directional distribution of molecular ensembles is isotropic, as in the present case. Detailed comparisons of the experimental outcome with theoretical results are indispensable for a deeper understanding of the underlying physics.…”

Laser-controlled electronic symmetry breaking in a phenylene ethynylene dimer: Simulation by the hierarchical equations of motion and optimal control

“…Our goal concerns the timely issue of optimizing control procedures for quantum systems strongly coupled to struc- * michele.desouter-lecomte@universite-paris-saclay.fr tured environments and leading to non-Markovian reduced dynamics. This requires implementing an optimization procedure of the parametric space among numerous available methods [17][18][19][20][21][22][23][24] with an efficient treatment of non-Markovian open systems [16,[25][26][27]. There are two main ways to account for the non-Markovianity reviewed for instance in reference [28].…”