We review the development of time-dependent close-coupling method to study atomic and molecular few body dynamics. Applications include electron photon collisions with atoms, molecules, their ions.

We address an efficient scheme to generate a broadband extreme-ultraviolet (xuv) continuum from high-order harmonic generation emerging the concept of plasmonic field enhancement in vicinity metallic nanostructures [Kim et al., Nature (London) 453, 757 (2008)]. Based on numerical solution time-dependent Schr\"odinger equation, for moderate intensities and depending inhomogeneity field, we are able increase plateau region roughly by factor two xuv continuum. The underlying physics plasmon is...

The results of a theoretical investigation the coherent interaction between many Rydberg atoms are reported. assumed to move very little during time range we investigate. We describe basic and show that (contrary previous studies) can be coherent. band structure for perfect lattice density states an amorphous distribution presented. also give when roughly positioned in lattice. Finally, performed detailed calculations understand interactions too strong essential type approximation. relevance...

We study the effect of resonances associated with complex molecular interaction Rydberg atoms on blockade. show that densely spaced potentials between doubly excited atomic pairs become unavoidably resonant optical excitation at short interatomic separations. Such limit coherent control individual excitations in As an illustration, we compute Rb near $100s$ states asymptote to characterize such detrimental and determine loss rate molecules inhomogeneous light shifts. Techniques avoid...

We propose a protocol for creating fully entangled GHZ-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum involving all ensemble. The necessary entanglement distant ensembles is mediated by single-photon channels collectively enhanced light-matter couplings. These techniques can be used create recently proposed clock...

It is commonly accepted in the strong-laser physics community that dynamical regime of atomic ionization characterized by Keldysh parameter $\ensuremath{\gamma}$. Two distinct cases, where $\ensuremath{\gamma}<1$ and $\ensuremath{\gamma}>1$, are associated with mechanisms predominantly tunneling multiphoton regimes, respectively. We perform fully three-dimensional quantum simulations for hydrogen atom solving time-dependent Schr\"odinger equation a wide range laser parameters encoded...

We have studied the radiative decay of atomic hydrogen in strong magnetic fields up to $4\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. followed cascade from completely $l,m$ mixed distributions highly excited states as well that involve with $\ensuremath{\mid}m\ensuremath{\mid}\ensuremath{\sim}n$. found time it takes populate ground state is not affected by field for initial $n\ensuremath{\lesssim}20$. For higher $n$ manifolds, electrons most negative $m$ are substantially slowed down resulting a...

We present results of our simulations the ionization a hydrogen atom excited to Rydberg wave packet in presence external parallel electric and magnetic fields. This is an example open, quantum system whose classical counterpart has been shown display chaos time domain. Within framework mechanics, electrons escape through induced pulse trains. reproduce such previously observed signatures time-dependent current ionizing study interference effects between outgoing trains which absent picture....

We develop a theoretical understanding of the trapping divalent Rydberg atoms in optical lattices. Because size electron cloud can be comparable to scale spatial variations laser intensity, we pay special attention averaging fields over atomic wave functions. The potential is proportional ac Stark polarizability. find that independent-particle approximation for valence electrons, this polarizability breaks into two contributions: singly ionized core and contribution from electron. Unlike...

Ponderomotive energy shifts experienced by Rydberg atoms in optical fields are known to be well approximated the classical quiver of a free electron. We examine such quantum mechanically and elucidate how they relate ponderomotive shift electron off-resonant fields. derive evaluate corrections free-electron polarizability length velocity (transverse or Coulomb) gauges, which agree exactly as mandated gauge invariance. also show value emerges from Dirac equation through summation over sea...

Motivated by compelling advances in manipulating cold Rydberg (Ry) atoms optical traps, we consider the effect of large extent a Ry electron wave function on trapping potentials. We find that, when orbit lies outside inflection points laser intensity landscape, atom can stably reside maxima. Effectively, free-electron ac polarizability is modulated landscape and accept both positive negative values. apply these insights to determining magic wavelengths for Ry-ground-state transitions...

We investigate the wavelength scaling of high-order-harmonic-generation (HHG) efficiency by few-cycle laser pulses where influence carrier-envelope phase (CEP) becomes prominent. Based on numerical solution time-dependent Schr\"odinger equation, in infrared region $\ensuremath{\lambda}$ (0.8--1.8 $\ensuremath{\mu}$m), we observe that power law form ${\ensuremath{\lambda}}^{\ensuremath{-}x}$ ($x\ensuremath{\approx}5$--6) is still present; but for constant intensity and a fixed energy...

We predict the possibility of 'triply magic' optical lattice trapping neutral divalent atoms. In such a lattice, and clock states an additional Rydberg state experience identical potentials, fully mitigating detrimental effects motional decoherence. particular, we show that this triply magic condition can be satisfied for Yb atom at wavelengths various other systems (Ca, Mg, Hg Sr) in UV region. assess quality triple conditions by estimating probability excitation out ground as result...

Because the commonly adopted viewpoint that Keldysh parameter $\ensuremath{\gamma}$ determines dynamical regime in strong field physics has long been demonstrated to be misleading, one can ask what happens as relevant physical parameters, such laser intensity and frequency, are varied while is kept fixed. We present results from our one- fully three-dimensional quantum simulations of high-order-harmonic generation (HHG) various bound states hydrogen with $n$ up 40, where intensities...

Intensity-modulated optical lattice potentials can change sign for an alkali-metal Rydberg atom, and the atoms are not always attracted to intensity minima in lattices with wavelengths near CO${}_{2}$ laser band. Here we demonstrate that such IR be tuned so trapping potential experienced by atom made vanish ``targeted'' states. Such state-selective of useful controlled cold collisions, cooling states, species-selective transport lattices. We tabulate at which vanishes $ns$, $np$, $nd$ states...

When atoms are exposed to intense laser or microwave pulses ~10% of the found in Rydberg states subsequent pulse, even if it is far more than required for static field ionization. The optical spectra surviving Li presence a 38 GHz suggest how survive an pulse. exhibit periodic train peaks apart. One peak just below limit, and with 90 V/cm amplitude extends from 300 above limit 3000 it. quantum mechanical calculations imply that quasi stable which electron weakly bound orbit infrequently...

Received 1 February 2012DOI:https://doi.org/10.1103/PhysRevA.85.029905©2012 American Physical Society

We report on our simulations of the generation high-order harmonics from atoms driven by an intense femtosecond laser field in presence noise. numerically solve non-perturbative stochastic time-dependent Schrodinger equation and observe how varying noise levels affect frequency components high harmonic spectrum. Our calculations show that when optimum amount is present driving field, roughly a factor 45 net enhancement can be achieved yield, especially, around cut-off region. that, for...

We have performed classical and quantum calculations for a hydrogen atom in strong magnetic field exposed to parallel electric that linearly increases with time. The were the situation where electron is launched from near nucleus microcanonical ensemble. For case of low angular momentum, are compared. show there exist stable trajectories at positive energy these contribute possibility surviving fields. dependence survival probability versus strength can be used estimate behaviour Rydberg...

The photo-double ionization cross section for the helium atom is calculated in near-threshold region by direct solution of time-dependent Schrodinger equation. Full close-coupling results 1s21S ground state are found to be excellent agreement with experimental measurements. calculations confirm validity Wannier power law from 0.1 eV about 1.7 excess energy and find no oscillations threshold beyond numerical uncertainty. Further made a simpler s-wave counterlinear model both 1s2s 1S excited...

A recent experiment showed that significant population transfer for a ∼10 photon resonance could be obtained with relatively small chirp in the light field. The system investigated was microwave transition between Rydberg states Li from n = 72, ℓ 1 to ∼ 82. This is multiphoton one-electron system. We present quantum calculations using model one-dimensional and fully three-dimensional agree measured results original interpretation of as an adiabatic passage through resonance. Although...

Efficient population transfer by adiabatically chirping through a multiphoton resonance in microwave driven and kicked Rydberg atoms has recently been reported both experimentally theoretically. Here we report on our simulations which have exploited this mechanism to vibrationally excite diatomic molecule up |ν = 4, J from the ground state four-photon condition. This is an efficient means of transfer, alternative ladder climbing scheme requiring sequence states correct order. We discuss...

Dynamically rich nature of the high-order harmonic generation process lends itself to a variety ways increase photon yield and extend cut-off frequency. We show here that high-harmonic from an atom confined inside attractive potential shell can dramatic in certain cases. consider endohedrally hydrogen C$_{60}$ cage as example, three distinct physical situations which initial state is (1) entirely C$_{60}$, (2) partially outside, (3) mainly localized on wall. demonstrate when atom-cage system...

We investigate the effect of series perturbation on second order dipole-dipole interactions between strontium atoms in $5sns({^1}S_0)$ and $5snp({^1}P_1)$ Rydberg states as a means engineering long-range atoms. The these enables modifying strength sign interaction by varying principal quantum number $n$ electron. utilize experimentally available data to estimate importance perturber states, find that van der Waals two shows strong peaks outside anticipated hydrogenic $n^{11}$ scaling....

We report results from collinear time-dependent close-coupling (TDCC), distorted-wave (DW), and $R$ matrix with pseudostates calculations for the electron-impact ionization of H-like ions up to $Z=6$ within an $s$-wave model. compare these those a classical trajectory Monte Carlo calculation investigate correspondence between quantal probabilities as principal quantum number initial state increases. In model calculations, electron-electron interaction is represented by potential given...