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Journal of Physics B: Atomic, Molecular and Optical Physics - latest papers

Latest articles for Journal of Physics B: Atomic, Molecular and Optical Physics

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  • Non-Hermitian exceptional points regulation of cascaded four-mode quantum squeezing in four-wave mixing processes
    Level-cascaded four-wave mixing systems with multimode quantum state squeezing are of great significance for non-Hermitian exceptional control. In this paper, based on non-Hermitian systems, we couple the energy level dressing to generate multimode quantum correlated beams. We have conducted an in-depth discussion on the quantum squeezing characteristics of the cascaded four-mode system. We use the gain squeezing matrix of the Hamiltonian matrix to introduce a pair of Einstein–Podolsky–Rosen (EPR) injections and two pairs of EPR injections at different positions in the cascaded four-mode system. We found several key phenomena: (1) In covariance squeezing, dual EPR injections not only disrupt the original squeezing strength but also produce varying numbers of Hamiltonians depending on injection location; (2) For intensity-difference squeezing, multiple coherent injections enhance squeezing coherence proportionally to injection count, while increased Hamiltonians strengthen intensity-difference correlations. Particularly noteworthy is the equivalence between single EPR injections and dual injections, as well as between position-B dual EPR injections and triple injections. The results establish that EPR injections exhibit superior intensity hierarchy compared to multiple coherent or Hamiltonian injections, with their configuration capable of actively modifying inter-mode hierarchical relationships.

  • Wavelength-dependent photodissociation of MgH+ via intermediate resonances
    We study by means of theoretical and numerical methods the resonance-enhanced two-photon dissociation of the MgH+ molecule, driven by narrow-band Gaussian laser pulses of various parameter values. Fine tuning the photon wavelength in the energy region of an intermediate electronic state ( –310 nm), we reveal rich nuclear dynamics, including Rabi oscillations and dynamic interference. Upon solving the time-dependent Schrödinger equation of the nuclei, the fingerprints of these dynamical effects are identified in the energy spectrum of the emitted molecular fragments. We also show that the dipole coupling between the intermediate resonances and the vibrational continuum varies very sensitively with the photon wavelength, allowing for an efficient control of the depletion, and of the bound-state dynamics of the molecule.

  • Photoelectron capture in processes of near-threshold atomic inner-shell photoionization followed by inner-vacancy sequential x-ray radiative and Auger decays
    Photoelectron capture in the course of sequential x-ray radiative and Auger decays (SRAD) after near-threshold atomic inner-shell photoionization has been studied. A many-body quantum theory of the SRAD processes has been developed based on the Hartree–Fock approximation in order to take into account the photoelectron recapture process. Photoelectron capture is considered as a post-collision interaction effect along with photoionization within a uniform quantum-mechanical approach. The theory developed has been applied to the processes of electron photoionization and recapture following the 1s-shell ionization of Ar. Detailed analysis of the relative contributions of electron photoionization and recapture processes to the energy spectra of Auger electron emission has been performed. The fine resonance structure of the Auger electron spectra connected with electron capture is predicted. Good agreement between the obtained theoretical results and available experimental data on the Auger electron spectrum is achieved.

  • Revisiting quantum memory efficiency using quantum coherence functions
    We show that a two-sided hybrid optomechanical (OM) system is capable of storing and retrieving information with controllable memory efficiency. The control of OM coupling, primarily arising from optomechanically induced transparency, plays a central role in our approach. By introducing an effective optical depth (OD) associated with the OM interaction, we analyze its impact on quantum memory efficiency and contrast it with the limitations imposed by the OD in Jaynes–Cummings-type coupling. Our study is based on the evaluation of first-order and second-order correlation functions, providing insight into coherence and quantum statistics. All parameters considered are within experimentally feasible regimes, highlighting the practical potential of the proposed quantum memory architecture.

  • The influence of positron-Xe elastic scattering cross section variation on ⟨ Z ...
    In this study, we investigated the sensitivity of the positron annihilation rate during thermalization to variations in the elastic scattering phase shifts and the corresponding cross sections. We employed a Boltzmann equation solver to simulate positron thermalization and calculate the average effective electron number, , which is proportional to the annihilation rate. Our analysis demonstrates that variations in phase shifts, even within experimentally reasonable error margins, lead to large uncertainties in the relaxation profiles. The implication is that improving the accuracy of scattering cross section measurements does not substantially reduce uncertainties in annihilation rates, but conversely, experimental measurements of can constrain the range of consistent positron scattering cross sections.