Coherent control: Principles and semiclassical implementations

Michal Hausner, Vít Procházka, Vlastimil Vrba

Creating a coherent source of gamma radiation remains one of the biggest motivations in gamma-ray optics. Such a source would utilize the stimulated emission of gamma photons. However, to achieve lasing in the high-energy regime other physical principles such as the lasing without inversion are needed to be explored. One of the currently developed approaches uses coherent control of gamma radiation waveforms to induce transparency in a medium by applying ultra-acoustic vibrations. In this paper a theoretical description of the stimulated emission and coherent control of gamma rays is developed on the basis of a one-dimensional quantum mechanical formalism. The model of the gamma radiation coherent control shows a good agreement with the conventional semiclassical description of the phenomenon. The model of the stimulated emission was developed with the assumptions which enable to propose a specific experimental arrangement for simultaneous detections of pairs of gamma photons. This proposal is further discussed in the context of the experimental observation of the stimulated emission of gamma photons.

Debabrata Goswami, Arvinder S. Sandhu

André D. Bandrauk, Michel C. Delfour, Claude Le Bris

Molecular alignment and orientation: From laser-induced mechanisms to optimal control by O. Atabek and C. M. Dion Overview and software guide of evolutionary algorithms A case study in quantum control by A. Auger, A. Ben Haj-Yedder, and M. Schoenauer Laser control of molecular states--Nonperturbative examples by A. D. Bandrauk, F. Legare, and H. T. Yu Coherent control: Principles and semiclassical implementations by V. S. Batista and P. Brumer Mathematical models of contemporary elementary quantum computing devices by G. Chen, D. A. Church, B.-G. Englert, and M. S. Zubairy Addendum and remarks on doubly conservative numerical schemes for the nonlinear Schrodinger equation and its control by M. C. Delfour A note on the exact internal control of nonlinear Schrodinger equations by R. Illner, H. Lange, and H. Teismann Towards efficient numerical approaches for quantum control by C. Le Bris, Y. Maday, and G. Turinici Multichannel quantum defect study of the control in the frequency domain: Example of HI by H. Lefebvre-Brion Development of solution algorithms for quantum optimal control equations in product spaces by Y. Ohtsuki and H. Rabitz Using contracted basis functions to solve the Schrodinger equation by X.-G. Wang and T. Carrington, Jr. Remarks on the controllability of the Schrodinger equation by E. Zuazua.

Warren S. Warren

Jabir Chathanathil, G. Liu, Svetlana Malinovskaya

A semiclassical theory that describes the generation of a coherent anti-Stokes Raman scattering (CARS) signal is presented that maximizes vibrational coherence in a mode predetermined by the pump, the Stokes, and the probe chirped pulse trains and takes into account the field propagation effects in a cloud of molecules. The buildup of the anti-Stokes signal, which may be used as a molecular signature in the backward CARS signal, is demonstrated numerically. The theory is based on the solution of the coupled Maxwell's and Liouville--von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. A deep convolutional neural network technique is implemented to evaluate time-dependent phase characteristics of the control fields. The effect of decoherence induced by spontaneous decay and collisional dephasing is examined.

Mohan Sarovar