Orbital-angular-momentum partition in hydrogen photoionization by a monochromatic vortex beam

@misc{xing2026orbitalangularmomentum,
  title = {{Orbital-angular-momentum partition in hydrogen photoionization by a monochromatic vortex beam}},
  author = {Zhongchen Xing and Chengyin Wu and Zheng Li and Marcelo F. Ciappina},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.16825},
  eprint = {2609.16825},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.16825},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Orbital-angular-momentum partition in hydrogen photoionization by a monochromatic vortex beam
AU  - Zhongchen Xing
AU  - Chengyin Wu
AU  - Zheng Li
AU  - Marcelo F. Ciappina
PY  - 2026
DA  - 2026/09/15
PB  - arXiv
DO  - 10.48550/arxiv.2609.16825
UR  - https://arxiv.org/abs/2609.16825
AB  - Understanding how optical orbital angular momentum (OAM) is transferred to matter requires treating recoil and translational motion alongside the internal electronic dynamics. We develop a center-of-mass-resolved theory of one-photon ionization of hydrogen by a monochromatic Laguerre--Gaussian beam and show that the Bessel-vortex photoelectron predicted in fixed-target models is a preparation-dependent limit. For a sharply defined atomic center-of-mass momentum, the recoil records the photon-cone azimuth, and tracing over it generally destroys the coherence required for a pure electron vortex. In the small-transverse-retardation regime, the optical OAM is transferred predominantly to the center-of-mass motion and hence, in the laboratory frame, to the proton. Finite-retardation corrections redistribute angular momentum between center-of-mass and relative motion, while an additional correlation contribution to the electron and proton angular momenta can be tuned through the spatial uncertainty of the atomic center of mass. These results reveal atomic recoil as a key element of OAM transfer in photoionization.
ER  -