Stefano Spezia
Published: 2018-12
Total Pages: 0
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Femtosecond physics is a novel branch of the theoretical physics, which investigates the interaction of atoms and molecules with pulsed or continuous wave lasers. In particular, this book treats the laser-matter coupling in a non-perturbative way using both approximate and numerical solutions of the Time-Dependent Schrödinger Equation (TDSE). Here, with the exception of one case study, the electromagnetic field is classically treated. Several physical phenomena ranging from ionization of atoms and molecules to their dissociation and the control of photochemical reactions are presented and discussed. This book begins with a wide Section 1, which deals with the TDSE and in particular, with its solutions. Initially, it considers only those cases exactly soluble, such as a class of potentials for which the TDSE with position-dependent mass allows reduction to a stationary Schrödinger equation, a time-dependent anharmonic oscillator, and at last, the derivation of a general form of the imaginary effective potential that relates the TDSE to the generalized Schrödinger equation with a memory kernel. Section 2 focuses on the field-matter interaction in quantum two-level systems, and in particular, a derivation of analytic broadband /2 and pulses that perform exact, or asymptotically exact, excitation of spin systems, presenting a nontrivial dynamic connection between nonlinear spin and linear spring systems. Finally, the last Section 3 considers several cases of atoms and molecules in strong laser fields. In detail, this section discusses a kinematic mechanism underlying the recently discovered 'near-zero energy structure' in the photoionization of atoms in strong mid-infrared laser fields and presents a number of benchmark calculations for intense short-pulse laser interactions with small atoms and molecules. Moreover, Section 3 presents a theoretical approach to investigate the high-order harmonic generation in the nano-graphene molecules and describes the few-electron ultrastrong light-matter coupling in a quantum LC circuit. Book jacket.