Related papers: Universal features in sequential and nonsequential…
We calculate the photo-ionization cross-section from the ground state of the helium atom, using the complex rotation method and diagonalization of sparse matrices. This produces directly the positions and widths of the doubly excited 1Po…
Double photoionization by a single photon is often discussed in terms of two contributing mechanisms, {\it knock-out} (two-step-one) and {\it shake-off} with the latter being a pure quantum effect. It is shown that a quasi-classical…
We report on the observation of phase space modulations in the correlated electron emission after strong field double ionization of helium using laser pulses with a wavelength of 394~nm and an intensity of $3\cdot10^{14}$W/cm$^2$. Those…
We show that temporal two-photon interference effects involving the signal and idler photons created by parametric down-conversion can be fully characterized in terms of the variations of two length parameters--called the biphoton…
We predict a significant delay of two-electron photoemission from the helium atom after absorption of an attosecond XUV pulse. We establish this delay by solving the time dependent Schr\"odinger equation and by subsequent tracing the…
We consider the two-point correlation function of the photodissociation cross section in molecules where the fragmentation process is indirect, passing through resonances above the dissociation threshold. In the limit of overlapping…
We provide a detailed quantum treatment of the spectral characteristics and of the dynamics of nondispersive two-electron wave packets along the periodically driven, collinear frozen planet configuration of helium. These highly correlated,…
Elliptical dichroism is known in atomic photoionization as the difference in the photoelectron angular distributions produced in nonlinear ionization of atoms by left- and right-handed elliptically polarized light. We theoretically…
Isotopic substitution in molecular systems can affect fundamental molecular properties including the energy position and spacing of electronic, vibrational and rotational levels, thus modifying the dynamics associated to their coherent…
Amplitude and phase of wavepackets encode the dynamics of quantum systems. However, the rapidity of electron dynamics on the attosecond timescale has precluded their complete measurement in the time domain. Here, we demonstrate that…
We investigate the photon statistics of an ensemble of coherently driven non-interacting two-level atoms in the weak driving regime. As it turns out, the system displays unique emission characteristics that are strongly in contrast to the…
We study the full field and frequency filtered output photon statistics of a resonator in thermal equilibrium with a bath and containing an arbitrarily large quartic nonlinearity. According to the general theory of photodetection, we derive…
The shape and absolute values of the generalized cross-sections of the two-photon resonant single ionization of the K-shell of ions of the isonuclear sequence of a heavy nickel atom (28Ni - Ni26+ - Ni24+ - Ni18+) have been theoretically…
Entanglement swapping and heralding are at the heart of many protocols for distributed quantum information. For photons, this typically involves Bell state measurements based on two-photon interference effects. In this context, hybrid…
We study the origin of dichroic effects in elastic scattering of high energy electrons by hydrogen atoms in the presence of a two-color bicircular laser field of commensurate frequencies, in the domain of moderate intensities below 10…
The nonlinear photon-photon interaction mediated by a single two-level atom is studied theoretically based on a one-dimensional model of the field-atom interaction. This model allows us to determine the effects of an atomic nonlinearity on…
Streaked photoelectron emission spectra access the correlated dynamics of photoelectrons and residual target electrons with attosecond temporal resolution. We calculated ab initio single-ionization spectra for photoemission from helium…
We calculate various differential and double differential characteristics of ionization by a single photon for H$^-$, He and for the two-electron ions with Z=3,4,5 in the region of the so-called quasi-free mechanism (QFM) domination. We…
We report experimental and theoretical investigations on photon diffusion in a second-order nonlinear disordered medium under conditions of strong nonlinearity. Experimentally, photons at the fundamental wavelength ($\lambda=1064$ nm) are…
The calculation of partial two-photon ionization cross sections in the above-threshold energy region is discussed in the framework of exterior complex scaling. It is shown that with a minor modification of the usual procedure, which is…