Dipole and Quadrupole Contributions to Photoionization Time Delay in Atoms

D. K. Keating, Steven Trent Manson, V. K. Dolmatov +3 more

J P Connerade, V. K. Dolmatov, Steven Trent Manson

Ankur Mandal, Soumyajit Saha, Narenda Nath Dutta +5 more

Pratikshya Parajuli

Early investigations of the photoionization time delay focused solely on dipole contributions at low-energy. Later experimental progress demonstrated that non-dipole time delays are also measurable. This motivated us to initiate a theoretical program aimed at studying detailed quadrupole time delays in the noble gasses Ne and Ar and assessing their physical significance. In this work, we examined the angular dependence of the quadrupole photoemission time delay for Ne and Ar using the Relativistic-Random-Phase Approximation (RRPA) method. Our approach began with identifying the relevant transitions for each sub-shell and obtaining the corresponding expression for the transition amplitude. From these amplitudes, we extracted the phase and computed the associated non-dipole time delay as a function of emission angle and energy for each sub-shell. Where applicable, we evaluated the time delay across both low- and high-energy regions and compared subshells that share the same principal quantum number n. These comparisons reveal the substantial influence of relativistic interactions between different subshells and atomic species. Currently, we have obtained results for Ne and Ar for the subs-hells ns1/2, np1/2, np3/2. Future work will extend these calculations to additional atomic systems, including heavier noble gasses, various atomic ions, and confined atomic environments.

Sourav Banerjee, Pranawa C. Deshmukh, Anatoli S. Kheifets +2 more

The angular dependence of Wigner-Eisenbud-Smith photoionization time delay has been investigated for the nd → ε f dipole channels in atomic Zn, Cd and Hg using the relativistic random phase approximation (RRPA). The studies have been carried out also in the nonrelativistic limit. This technique enables identification of the relativistic effects on the angular dependence of photoionization time delay.

Saumyashree Baral, Raghavan K. Easwaran, Jobin Jose +2 more

An atom confined in an optical dipole trap is a promising candidate for a qubit. Analyzing the temporal response of such trapped atoms enables us to estimate the speed at which quantum computers operate. The present work models an atom in an optical dipole trap formed using crossed laser beams and further examines the photoionization time delay from such confined atoms. We study noble gas atoms, such as Ne (Z = 10), Ar (Z = 18), Kr (Z = 36), and Xe (Z = 54). The atoms are considered to be confined in an optical dipole trap using X-ray Free Electron Lasers (XFEL). The present work shows that the photoionization time delay of the trapped atoms is different compared with that of the free atoms. This analysis alerts us that while talking about the speed of quantum computing, the temporal response of the atoms in the trapped environment must also be accounted for.