Strong in this context means that the electric field of the laser brings the state of the target system far away from the initial, typically ground-state, configuration, they say, which means that the standard textbook quantum mechanical

perturbation theory is not applicable, and interesting non-perturbative phenomena appear, such as high-order above-threshold ionization or high-harmonic generation.

New relations and dualities involving scattering amplitudes may become manifest only through their actual calculations at higher orders in

perturbation theory, yet invisible to the canonical approach to quantum field theory.

In view of the above, a new multicast tree update strategy based on

perturbation theory Musp (Multicast Update Strategy based on

Perturbation theory) is proposed, which reduces the data transmission interruption caused by the multicast tree update and improves user experiences.

2009) or cosmological

perturbation theory (Gumrukcuoglu et al.

According to the matrix

perturbation theory, the singular values of a matrix are of good stability [24], so are the singular vectors.

MEG in nm-sized hydrogen-passivated silicon nanowires (NWs), and quasi two-dimensional nanofilms depends strongly on the degree of the core structural disorder as shown by the many-body

perturbation theory (MBPT) calculations based on the DFT simulations.

PETKOV,

Perturbation Theory for Matrix Equations, North-Holland, Amsterdam, 2003.

New research direction in singular

perturbation theory artificial parameter approach and inverse perturbation technique Math.

This analysis is carried out by examining all possible interactions between "filled" (donor) Lewis-type NBOs and "empty" (acceptor) non-Lewis NBOs, and estimating their energetic importance by 2nd-order

perturbation theory.

Sophisticated applications of

perturbation theory and other quantum theoretical calculations, explorations of the magnetic field effect and plasma surface modification, and calculated biological activities of interesting organic molecules are presented here.

With xPan d, deriving perturbation equations up to any order in

perturbation theory and for any metric theory of gravity becomes very simple

Elements of

perturbation theory and asymptotic analysis; 2.