物理学前沿：英文版

Exact wave functions for atomic electron interacting with photon fields

Dongsheng, Guo

Published Jan 1, 2013• 0 citations

Abstract

Many nonlinear quantum optical physics phenomena need more accurate wave functions and corresponding energy or quasienergy levels to account for. An analytic expression of wave functions with corresponding energy levels for an atomic electron interacting with a photon field is presented as an exact solution to the SchrSdinger-like equation involved with both atomic Coulomb interaction and electron-photon interaction. The solution is a natural generalization of the quantum-field Volkov states for an otherwise free electron interacting with a photon field. The solution shows that an N- level atom in light form stationary states without extra energy splitting in addition to the Floquet mechanism. The treatment developed here with computing codes can be conveniently transferred to quantum optics in classical-field version as research tools to benefit the whole physics community.

Related papers

Exact wave functions for atomic electron interacting with photon fields

Dong‐Sheng Guo

Many nonlinear quantum optical physics phenomena need more accurate wave functions and corresponding energy or quasienergy levels to account for. An analytic expression of wave functions with corresponding energy levels for an atomic electron interacting with a photon field is presented as an exact solution to the Schrödinger-like equation involved with both atomic Coulomb interaction and electron-photon interaction. The solution is a natural generalization of the quantum-field Volkov states for an otherwise free electron interacting with a photon field. The solution shows that an N level atom in light form stationary states without extra energy splitting in addition to the Floquet mechanism. The treatment developed here with computing codes can be conveniently transferred to quantum optics in classical-field version as research tools to benefit the whole physics community.

Frontiers of PhysicsFeb 1, 20133 citations

Atomic Floquet physics revealed by free electrons

Eduardo Arqué López, Valerio Di Giulio, F. Javier Garcı́a de Abajo

We theoretically investigate the ability of free electrons to yield information on the nonlinear Floquet dynamics of atomic systems subject to intense external illumination. By applying a quantum-mechanical formalism to describe the atom-electron interaction under the presence of a monochromatic classical light field, we observe multiple energy features that reveal a large departure from nonillumination conditions in two- and three-level illuminated atoms, including the emergence of energy features associated with direct photon absorption and emission by the electron, as well as a varied set of Floquet resonances that strongly depend on the light intensity and frequency. Our results unveil a wealth of effects associated with the interaction between free electrons and optically driven electronic systems.

arXiv:2111.08675Physical Review ResearchMar 29, 202212 citations

Quantum Optical Aspects of High-Harmonic Generation

Sándor Varró

The interaction of electrons with strong laser fields is usually treated with semiclassical theory, where the laser is represented by an external field. There are analytic solutions for the free electron wave functions, which incorporate the interaction with the laser field exactly, but the joint effect of the atomic binding potential presents an obstacle for the analysis. Moreover, the radiation is a dynamical system, the number of photons changes during the interactions. Thus, it is legitimate to ask how can one treat the high order processes nonperturbatively, in such a way that the electron-atom interaction and the quantized nature of radiation be simultaneously taken into account? An analytic method is proposed to answer this question in the framework of nonrelativistic quantum electrodynamics. As an application, a quantum optical generalization of the strong-field Kramers-Heisenberg formula is derived for describing high-harmonic generation. Our formalism is suitable to analyse, among various quantal effects, the possible role of arbitrary photon statistics of the incoming field. The present paper is dedicated to the memory of Prof. Dr. Fritz Ehlotzky, who had significantly contributed to the theory of strong-field phenomena over many decades.

arXiv:2407.04755PhotonicsJul 9, 202121 citations

Scattering theory of multiphoton ionization in strong fields

Dong‐Sheng Guo, Teijo Åberg, Bernd Crasemann

Formal time-independent scattering theory is applied to multiphoton ionization of atoms in intense electromagnetic fields. The quantized-field version of the Volkov solution makes this approach possible. With the electron-photon interaction in a monochromatic photon field, it is found that, in the nonrelativistic and large-photon-number limits, the final scattering state exists only in the special case in which the ponderomotive potential per unit photon energy is an integer; otherwise the final state vanishes. In the integer case the corresponding wave function reduces to a single Volkov function, multiplied by an overlap factor. A simple interpretation of this result is given, and some other consequences of this work are discussed.

Physical Review ANov 1, 1989127 citations

Atom–Field Interaction

Partha Pratim Mondal

The interaction of electromagnetic fields with atomic/molecular systems is the genesis of most optical phenomena observed to date. To explain these effects, we need two broad classifications based on both classical and quantum theories. This strategy involves treating (1) fields as classical systems and atoms as quantum systems having discrete energy, (2) fields as quantum systems (particles rather than waves) and atomic systems as classical, or (3) both as quantum systems. Of course, schemes 1 and 2 are easy to solve and visualize, while scheme 3 is the most accurate description but complex in nature. In general, quantum approaches do not lead to exact solutions and require assumptions and simplifications to achieve a reasonably approximate solution. Thus, it is important to choose an appropriate strategy for solving a particular problem. The problem associated with atom–field interactions will also be subjected to different strategies to understand some of the experimentally observed phenomena such as Rabi oscillations. In this chapter, we will derive a master equation that serves as the starting point for solving a large number of problems associated with atom–field interactions.

May 25, 20220 citations

Interaction of a two-level atom with single-mode optical field beyond the rotating wave approximation

Ju Liu, Zhiyuan Li

One of the simplest models involving the atom-field interaction is the coupling of a single two-level atom with single-mode optical field. Under the rotating wave approximation, this problem is reduced to a form that can be solved exactly. But the approximation is only valid when the two levels are resonant or nearly resonant with the applied electromagnetic radiation. Here we present an analytical solution without the rotating wave approximation and applicable to general atom-field interaction far away from the resonance. We find that there exists remarkable influence of the initial phase of optical field on the Rabi oscillations and Rabi splitting, and this issue cannot be explored in the context of the rotating wave approximation. Due to the retention of the counter-rotating terms, higher-order harmonic appears during the Rabi splitting. The analytical solution suggests a way to regulate and control the quantum dynamics of a two-level atom and allows for exploring more essential features of the atom-field interaction.

Optics ExpressNov 10, 201412 citations