scholarly journals Application of the Phase-Space Path Integral to Strong-Laser-Field-Assisted Electron-Ion Radiative Recombination: A Gauge-Covariant Formulation

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1606
Author(s):  
Ali Esquembre Kučukalić ◽  
Wilhelm Becker ◽  
Dejan B. Milošević
Keyword(s):  
Phase Space ◽  
Path Integral ◽  
Laser Field ◽  
Radiative Recombination ◽  
Strong Field ◽  
Transition Amplitude ◽  
Energy Operator ◽  
Strong Laser Field ◽  
Space Matrix ◽  
Velocity Gauge

We consider the problem of the choice of gauge in nonrelativistic strong-laser-field physics. For this purpose, we use the phase-space path-integral formalism to obtain the momentum-space matrix element of the exact time-evolution operator. With the assumption that the physical transition amplitude corresponds to transitions between eigenstates of the physical energy operator rather than the unperturbed Hamiltonian H0=(−i∂/∂r)2/2+V(r), we prove that the aforementioned momentum-space matrix elements obtained in velocity gauge and length gauge are equal. These results are applied to laser-assisted electron-ion radiative recombination (LAR). The transition amplitude comes out identical in length gauge and velocity gauge, and the expression agrees with the one conventionally obtained in length gauge. In addition to the strong-field approximation (SFA), which is the zeroth-order term of our expansion, we present explicit results for the first-order and the second-order terms, which correspond to LAR preceded by single and double scattering, respectively. Our general conclusion is that in applications to atomic processes in strong-field physics the length-gauge version of the SFA (and its higher-order corrections) should be used. Using the energy operator as the basis-defining Hamiltonian, we have shown that the resulting transition amplitude is gauge invariant and agrees with the form commonly derived in length gauge.

STRONG-FIELD REGIMES OF PHOTOIONIZATION

1995 ◽  
Vol 04 (04) ◽  
pp. 757-773
Author(s):  
M. V. FEDOROV
Keyword(s):  
Wave Packet ◽  
High Frequency ◽  
Laser Field ◽  
Strong Field ◽  
Strong Laser Field ◽  
Strong Laser ◽  
Atom Ionization

The main known regimes of atom ionization by a strong laser field are reviewed: the Kramers–Henneberger (high-frequency) and interference stabilization of atoms, barrier-suppression ionization and the model of wave packet spreading. The physics and relations between them are discussed.

Radiative recombination in a strong laser field: low-frequency approximation

2005 ◽  
Vol 22 (10) ◽  
pp. 2076 ◽  
Author(s):  
Saverio Bivona ◽  
Riccardo Burlon ◽  
Gaetano Ferrante ◽  
Claudio Leone
Keyword(s):  
Laser Field ◽  
Radiative Recombination ◽  
Low Frequency ◽  
Strong Laser Field ◽  
Strong Laser ◽  
Frequency Approximation

scholarly journals Simple man model in the Heisenberg picture

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
I. A. Ivanov ◽  
Kyung Taec Kim
Keyword(s):  
Laser Field ◽  
Numerical Solutions ◽  
Strong Field ◽  
Equations Of Motion ◽  
Field Ionization ◽  
Strong Laser Field ◽  
Strong Field Ionization ◽  
Velocity Autocorrelation ◽  
Different Types ◽  
Insight Into

AbstractDescribing the ionization of an atom exposed to a strong laser field entails computationally expensive quantum simulations based on the numerical solutions of the time-dependent Shrödinger equation. The well-known Simple Man Model provides a qualitatively accurate description of the ionization process. Here, we propose a quantum generalization of the physical picture given by the Simple Man Model. We describe an approximate solution to the Heisenberg operator equations of motion for an atom in a laser field. We provide justification of this generalization and test its validity by applying it to calculate the coordinate and velocity autocorrelation functions. Both our model and results of the ab initio numerical calculations show distinct types of correlations due to different types of electron’s motion providing insight into the strong field ionization dynamics.

Control of radiative recombination by a strong laser field

2004 ◽  
Vol 78 (7-8) ◽  
pp. 809-812 ◽  
Author(s):  
S. Bivona ◽  
R. Burlon ◽  
G. Ferrante ◽  
C. Leone
Keyword(s):  
Laser Field ◽  
Radiative Recombination ◽  
Strong Laser Field ◽  
Strong Laser

scholarly journals Attosecond streaking using a rescattered electron in an intense laser field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yang Hwan Kim ◽  
Igor A. Ivanov ◽  
Sung In Hwang ◽  
Kyungseung Kim ◽  
Chang Hee Nam ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Field ◽  
Strong Field ◽  
High Harmonic ◽  
Photoelectron Spectra ◽  
Intense Laser ◽  
Electron Trajectory ◽  
Strong Laser Field ◽  
New Type ◽  
Ultrashort Laser

AbstractWhen an atom or molecule is exposed to a strong laser field, an electron can tunnel out from the parent ion and moves along a specific trajectory. This ultrafast electron motion is sensitive to a variation of the laser field. Thus, it can be used as a fast temporal gate for the temporal characterization of the laser field. Here, we demonstrate a new type of attosecond streaking wherein a rescattered electron trajectory is manipulated by an ultrashort laser pulse. The vector potential of the laser pulse is directly recorded in the photoelectron spectra of the rescattered electron. In contrast to high harmonic generation methods, our approach has no directional ambiguity in space, leading to complete in situ temporal characterization. In addition, it provides timing information on ionization and re-scattering events. Therefore, our approach can be a useful tool for the investigation of strong-field processes triggered by rescattering, such as non-sequential double ionization and laser-induced electron diffraction.

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