Entangled Two-Photon Absorption in Cesium Atoms and the Limitations of the Far-Off-Resonance Approximation

• URL: http://arxiv.org/abs/2606.01318v1
• Date: Sun, 31 May 2026 16:09:22 GMT
• Title: Entangled Two-Photon Absorption in Cesium Atoms and the Limitations of the Far-Off-Resonance Approximation
• Abstract summary: We present a theoretical study of the ETPA process in cesium atoms.<n>The quantum state of light considered is described by the joint spectral amplitude of photon-pairs.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The discrepancies between theoretical and experimental results in the process of entangled two-photon absorption (ETPA) are not fully understood. Atomic systems are a promising alternative for investigating this process without the systematic effects present in molecules. We present a theoretical study of the ETPA process in cesium atoms, focusing on the 6S1/2 --> 8S1/2 transition. The ETPA cross section is evaluated both with and without the far-off-resonance (FOR) approximation, including the contributions from intermediate atomic states and decoherence effects. The quantum state of light considered is described by the joint spectral amplitude of photon-pairs produced by the spontaneous parametric down-conversion process. When the FOR approximation is applied, the enhancement factor is constant (36*pi). In contrast, without this approximation the enhancement factor oscillates with the entanglement time, and achieves a maximum value of ~500. These results show the limitations of approximations when calculating the ETPA cross section and contribute to the understanding of the discrepancies between theoretical and experimental values for the ETPA cross section in different samples. The numbers presented in this work can be a starting point for designing experiments aimed at measuring ETPA cross sections in alkali atoms.

Related papers

• Ab initio multichannel calculation of the Bethe surface and Compton defects for molecular hydrogen [45.88028371034407]
  A correlated computation of the generalized oscillator-strength density for electrons scattering off randomly oriented molecular hydrogen is presented.<n>The present findings are expected to be helpful for calculating highly accurate energy-loss spectra for electrons passing through and ionizing molecular hydrogen gas or its isotopologues.
  arXiv  Detail & Related papers  (2026-09-10T20:51:04Z)
• Accurate theoretical methods for photoionization of H$_2$ molecules [41.99844472131922]
  Single-photon ionization cross sections of molecular hydrogen in the electric dipole limit are numerically computed by employing three independent methods.<n>Both time-dependent and -independent approaches within the clamped-nuclei approximation at equilibrium internuclear distance are used.
  arXiv  Detail & Related papers  (2026-09-02T11:32:09Z)
• Measurement-induced state transitions across the fluxonium qubit landscape [73.92964306525622]
  We study measurement-induced state transitions in the fluxonium qubit over a wide range of parameters.<n>We find that lighter fluxoniums are less susceptible to these state transitions when compared to their heavier counterparts.<n>We attribute this effect to the combination of lower density of multi-photon resonances, a smaller requisite coupling for a given dispersive shift, and a more harmonic-like structure of the charge operator.
  arXiv  Detail & Related papers  (2026-04-09T17:53:41Z)
• Optimized spectral and interferometric techniques for the certification of ETPA [0.0]
  Entangled Two-Photon Absorption (ETPA) presents a persistent controversy in the literature.<n>This work introduces a key strategy to isolate the ETPA contribution through its spectral signature.<n>A preliminary experiment addressing the ETPA detection limits using the standard RhB dye is presented.
  arXiv  Detail & Related papers  (2025-11-30T22:24:15Z)
• Quantum Interference of Distinguishable Photons Based on Spatially-Resolved Measurements [67.410870290301]
  We present experimental results demonstrating the quantum interference of two photons distinguishable in their transverse momenta.<n>We contrast our results with a non-spatially resolved measurement where averaging over the photons' positions washes out the quantum interference observed in spatially resolved measurements.
  arXiv  Detail & Related papers  (2025-08-20T16:56:59Z)
• Asymmetric Biphoton Generation under Ground-State Decoherence and Phase Mismatch in a Cold Atomic Ensemble [0.0]
  We investigate how ground-state decoherence and phase mismatch influence biphoton generation in spontaneous four-wave mixing.<n>Our results reveal significant asymmetry in the Stokes and anti-Stokes photon generation rates.<n>Although ground-state decoherence reduces the generation of temporally correlated photons, it paradoxically enhances biphoton purity.
  arXiv  Detail & Related papers  (2025-05-10T13:57:57Z)
• Experimental evidence of quantum interferences in CO-H$_2$ rotational energy transfer at room temperature [44.99833362998488]
  Theoretically predicted quantum interferences in the CO-H$ collision$al system are experimentally observed for the first time at room temperature, and excellent agreement between theory and experiment is observed.<n>Results provide a valuable benchmark for validating the anisotropic part of the potential energy surface, thereby supporting the theoretical modeling of CO emission in warm astrophysical environments such as photodissociation regions.
  arXiv  Detail & Related papers  (2025-04-06T08:05:31Z)
• Multiband dispersion and warped vortices of strongly-interacting photons [36.939655407596426]
  We study quantum correlations between interacting photons realized through co-propagating Rydberg polaritons.<n>For three photons, the dispersion breaks the symmetry between a photon pair propagating ahead versus behind a single photon.
  arXiv  Detail & Related papers  (2025-02-17T08:35:10Z)
• Extending the coherence time limit of a single-alkali-atom qubit by suppressing phonon-jumping-induced decoherence [22.585565798915038]
  Coherence time of qubit encoded in electronic states is one of the most important parameters.<n>Coherence time is assumed to be determined by relative stability of the energy between the electronic states.<n>We propose a complete description of the decoherence of a qubit encoded in two ground electronic states of an optically trapped alkali atom.
  arXiv  Detail & Related papers  (2023-12-18T13:42:46Z)
• Entangled two-photon absorption detection through a Hong-Ou-Mandel interferometer [0.0]
  The ETPA process is detected based on the changes induced on the Hong-Ou-Mandel interferogram of two photons produced by a spontaneous parametric down conversion process. We present a detail model in which the sample is modeled as a filtering function which fullfills the energy conservation conditions required by ETPA.
  arXiv  Detail & Related papers  (2022-02-12T05:00:11Z)
• Entangled Two-Photon Absorption by Atoms and Molecules: A Quantum Optics Tutorial [0.0]
  Two-photon absorption (TPA) and other nonlinear interactions of molecules with time-frequency-entangled photon pairs (EPP) has been predicted to display a variety of fascinating effects. This paper presents a detailed theoretical study of one- and two-photon absorption by molecules, focusing on how to treat the quantum nature of light.
  arXiv  Detail & Related papers  (2021-03-03T17:46:46Z)
• Experimental study on the effects of photon-pair temporal correlations in entangled two-photon absorption [0.0]
  Entangled two-photon absorption (ETPA) has recently become a topic of lively debate. This work provides a thorough experimental study of ETPA in Rhodamine B and Zinc Tetraphenylporphirin.
  arXiv  Detail & Related papers  (2021-01-26T18:31:09Z)
• Setting bounds on two-photon absorption cross-sections in common fluorophores with entangled photon pair excitation [48.7576911714538]
  We use a fluorescence-based registration scheme to experimentally determine upper bounds on the cross-sections for six fluorophores. For two samples that have been studied by others, Rhodamine 6G and 9R-S, we measure upper bounds four and five orders of magnitude lower than the previously reported cross-sections.
  arXiv  Detail & Related papers  (2020-08-06T13:53:16Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.