Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Alexandria Engineering Journal

Modeling fluorescence as an entanglement witness and an alternative probe to EIT electrometry in four-level Rydberg systems

M. S. Ateto, Emad K. Jaradat

Published May 1, 2026• 0 citations
Publisher

Abstract

We investigate a four-level Rydberg atom in the V+ Θ configuration using the master equation formalism under a weak probe approximation. Analytical solutions for steady-state coherences reveal how control-field induced dressed states govern three key observables: resonance fluorescence, entanglement, and electromagnetically induced transparency (EIT). We show that fluorescence spectra encode the same interference pathways responsible for EIT, enabling fluorescence to serve as a robust alternative probe for Rydberg electrometry. Moreover, since fluorescence and subsystems’ entanglement derive from the same density-matrix coherences, spectral sidebands map directly onto peaks in entanglement, making fluorescence an experimentally accessible entanglement witness. A Stratonovich–Weyl Wigner function (SW) provides a unifying perspective: its negative regions, arising from interference-induced coherences, coincide with regimes of enhanced fluorescence and entanglement, establishing it as a general nonclassicality witness. This four-fold correspondence highlights the central role of dressed-state coherences in linking spectroscopy, electrometry, quantum correlations, and nonclassicality. Our work establishes a coherent mathematical framework for interpreting fluorescence as a complementary (and in certain regimes alternative) probe to EIT-based electrometry, as well as an experimentally accessible proxy for entanglement detection and nonclassicality.

DOI
10.1016/j.aej.2026.04.049

Related papers

Fluorescence as A Qualitative Electrometry Readout and Entanglement Indicator with A Stratonovich-Weyl Wigner Calibration Framework for Moving 4-Level Rydberg Atoms

Mohammed S. Ateto, Emad K. Jaradat, S Abo-Dahab

We present a unified, geometry-resolved framework for absorption, resonance fluorescence, entanglement, and phase-space quasiprobability in Doppler-broadened four-level Rydberg atoms. Within a density-matrix formalism incorporating velocity averaging and dressed-state analysis, these observables are shown to constitute complementary projections of a common coherence-driven structure governed by multi-photon interference. We further introduce the Stratonovich-Weyl (SW) Wigner function as a phase-space representation that encodes both population and coherence contributions on equal footing. A direct comparison reveals a near one-to-one correspondence between SW quasiprobability structures and entanglement landscapes, with coherence-induced features such as avoided crossings and detuning-dependent ridges preserved across representations. Isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the same coherence geometry underlying entanglement negativity. Resonance fluorescence emerges as a thermally robust and experimentally accessible observable: unlike absorption, it preserves spectral structure under Doppler averaging and reliably tracks dressed-state dynamics and entanglement extrema. Strong-field dressing and propagation geometry control the redistribution of coherence across velocity classes, leading to characteristic spectral asymmetries and ridge formation. These results establish a direct link between phase-space structure, spectroscopic observables, and quantum correlations in thermal media. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, this framework provides an experimentally accessible route for entanglement characterization without eigenvalue reconstruction, enabling Doppler-resilient, fluorescence-based quantum sensing in warm Rydberg systems.

•May 15, 2026•0 citations

Fluorescence as A Qualitative Electrometry Readout and Entanglement Indicator with A Stratonovich-Weyl Wigner Calibration Framework for Moving 4-Level Rydberg Atoms

Mohammed S. Ateto, Emad K. Jaradat, S Abo-Dahab

We present a unified, geometry-resolved framework for absorption, resonance fluorescence, entanglement, and phase-space quasiprobability in Doppler-broadened four-level Rydberg atoms. Within a density-matrix formalism incorporating velocity averaging and dressed-state analysis, these observables are shown to constitute complementary projections of a common coherence-driven structure governed by multi-photon interference. We further introduce the Stratonovich-Weyl (SW) Wigner function as a phase-space representation that encodes both population and coherence contributions on equal footing. A direct comparison reveals a near one-to-one correspondence between SW quasiprobability structures and entanglement landscapes, with coherence-induced features such as avoided crossings and detuning-dependent ridges preserved across representations. Isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the same coherence geometry underlying entanglement negativity. Resonance fluorescence emerges as a thermally robust and experimentally accessible observable: unlike absorption, it preserves spectral structure under Doppler averaging and reliably tracks dressed-state dynamics and entanglement extrema. Strong-field dressing and propagation geometry control the redistribution of coherence across velocity classes, leading to characteristic spectral asymmetries and ridge formation. These results establish a direct link between phase-space structure, spectroscopic observables, and quantum correlations in thermal media. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, this framework provides an experimentally accessible route for entanglement characterization without eigenvalue reconstruction, enabling Doppler-resilient, fluorescence-based quantum sensing in warm Rydberg systems.

•May 15, 2026•0 citations

Unified Phase-Space Mapping of Quantum Observables in a Multi-Driven Vapor: Resonance Fluorescence as an Electrometry Probe and Correlation Witness

M. S. Ateto, Emad K. Jaradat, S. M. Abo-Dahab

We present a unified, geometry-resolved framework for analyzing absorption, resonance fluorescence, entanglement negativity, and phase-space quasiprobability in Doppler-broadened four-level atomic vapor. Using a density-matrix formalism with thermal velocity averaging and exact dressed-state diagonalization, we show that these observables constitute complementary projections of a common coherence-driven phase-space structure governed by multiphoton interference. Central to this framework is the Stratonovich-Weyl (SW) Wigner function, which provides a unified phase-space representation incorporating both populations and coherences. Direct comparison reveals a near one-to-one correspondence between SW quasiprobability distributions and entanglement landscapes, with geometry-dependent features, including hyperbolic dispersion asymptotes and split resonance ridges, consistently preserved. Furthermore, isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the coherence geometry underlying entanglement negativity, providing a non-invasive quantum correlation witness. At the same time, resonance fluorescence emerges as a thermally robust observable: unlike susceptibility-based absorption, its additive pole weighting preserves sharp Autler-Townes spectral features under strong driving. This robustness enables fluorescence to accurately track bright dressed states and entanglement extrema despite severe Doppler dephasing, establishing its dual role as a sensitive electrometry probe and correlation witness. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, the proposed framework offers an experimentally accessible, eigenvalue-free approach to quantum state characterization, enabling Doppler-resilient fluorescence-based quantum sensing and precision field electrometry in warm atomic media.

quant-pharXiv:2607.10083•Jul 14, 2026•0 citations

Electromagnetically induced transparency spectroscopy of Rydberg levels dressed by linearly polarized rf fields: Complementary angular response for two types of transition ladders

Matthew Cloutman, Matthew Chilcott, Alexander Elliott +3 more

Rydberg atoms efficiently link photons between the radio-frequency (rf) and optical domains. They furnish a medium in which the presence of an rf field imprints on the transmission of a probe laser beam by altering the coherent coupling between atomic quantum states. The immutable atomic energy structure underpins quantum-metrological rf-field measurements and has driven intensive efforts to realize inherently self-calibrated sensing devices. Here, we investigate spectroscopic signatures owing to the quantization of atomic angular momentum. Using an electromagnetically induced transparency (EIT) sensing scheme, specific combinations of atomic terms are shown to give rise to universal, distinctive fingerprints in the detected optical fields upon rotating a linearly polarized rf field. Employing a dressed state picture, we identify two types of atomic angular momentum ladders that display strikingly disparate spectroscopic characteristics, including the distinctive absence or presence of a central spectral EIT peak. Our study adds important insights into the prospects of Rydberg atomic gases for quantum-metrological electric field characterization including polarimetry. In particular, it calls into question prevailing interpretations of SI-traceable Rydberg atom electrometers.

arXiv:2503.17997•Physical Review Research•Jun 5, 2026•1 citation

Electromagnetically induced transparency and electromagnetically induced absorption in Y-type system

Kalan Mal, Khairul Islam, Suman Mondal +2 more

The propagation of a probe field through a four-level Y-type atomic system is described in the presence of two additional coherent radiation fields, namely, the control field and the coupling field. An expression for the probe response is derived analytically from the optical Bloch equations under steady state condition to study the absorptive properties of the system under probe field propagation through an ensemble of stationary atoms as well as in a Doppler broadened atomic vapor medium. The most striking result is the conversion of electromagnetically induced transparency (EIT) into electromagnetically induced absorption (EIA) as we start switching from weak probe regime to strong probe regime. The dependence of this conversion on residual Doppler averaging due to wavelength mismatch is also shown by choosing the coupling transition as a Rydberg transition.

Chinese Physics B•Mar 11, 2020•5 citations

Nonlinear optical spectra from Rydberg-mediated photon-photon interactions

Xinghan Wang, Yupeng Wang, Aishik Panja +1 more

While Rydberg-Rydberg interactions are essential for quantum nonlinear optics and quantum information processing, their role in microwave and radio-frequency sensing remains poorly understood. Here we experimentally investigate Rydberg interaction-induced nonlinearity in cold-atom Rydberg electromagnetically induced transparency (EIT). In a three-level EIT system, increasing photon-photon interactions produces nonlinear spectral broadening accompanied by resonance shifts, while a microwave-dressed four-level system exhibits pronounced nonlinear broadening without detectable spectral shifts. Our three-level data can be explained by a conditional superatom model, whereas our four-level observations are surprisingly captured by a simple dephasing model. Comparisons with three representative models provide key insights to the role of many-body interactions in Rydberg EIT spectroscopy. Furthermore, our results clarify the conditions under which microwave field characterization can be performed in the nonlinear regime without introducing systematic bias. Our study advances both fundamental understanding of many-body physics and practical development of atomic sensors.

arXiv:2602.11563•Feb 12, 2026•0 citations
We investigate a four-level Rydberg atom in the V+ Θ configuration using the master equation formalism under a weak probe approximation. Analytical solutions for steady-state coherences reveal how control-field induced dressed states govern three key observables: resonance fluorescence, entanglement, and electromagnetically induced transparency (EIT). We show that fluorescence spectra encode the same interference pathways responsible for EIT, enabling fluorescence to serve as a robust alternative probe for Rydberg electrometry. Moreover, since fluorescence and subsystems’ entanglement derive from the same density-matrix coherences, spectral sidebands map directly onto peaks in entanglement, making fluorescence an experimentally accessible entanglement witness. A Stratonovich–Weyl Wigner function (SW) provides a unifying perspective: its negative regions, arising from interference-induced coherences, coincide with regimes of enhanced fluorescence and entanglement, establishing it as a general nonclassicality witness. This four-fold correspondence highlights the central role of dressed-state coherences in linking spectroscopy, electrometry, quantum correlations, and nonclassicality. Our work establishes a coherent mathematical framework for interpreting fluorescence as a complementary (and in certain regimes alternative) probe to EIT-based electrometry, as well as an experimentally accessible proxy for entanglement detection and nonclassicality.
We present a unified, geometry-resolved framework for absorption, resonance fluorescence, entanglement, and phase-space quasiprobability in Doppler-broadened four-level Rydberg atoms. Within a density-matrix formalism incorporating velocity averaging and dressed-state analysis, these observables are shown to constitute complementary projections of a common coherence-driven structure governed by multi-photon interference. We further introduce the Stratonovich-Weyl (SW) Wigner function as a phase-space representation that encodes both population and coherence contributions on equal footing. A direct comparison reveals a near one-to-one correspondence between SW quasiprobability structures and entanglement landscapes, with coherence-induced features such as avoided crossings and detuning-dependent ridges preserved across representations. Isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the same coherence geometry underlying entanglement negativity. Resonance fluorescence emerges as a thermally robust and experimentally accessible observable: unlike absorption, it preserves spectral structure under Doppler averaging and reliably tracks dressed-state dynamics and entanglement extrema. Strong-field dressing and propagation geometry control the redistribution of coherence across velocity classes, leading to characteristic spectral asymmetries and ridge formation. These results establish a direct link between phase-space structure, spectroscopic observables, and quantum correlations in thermal media. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, this framework provides an experimentally accessible route for entanglement characterization without eigenvalue reconstruction, enabling Doppler-resilient, fluorescence-based quantum sensing in warm Rydberg systems.
We present a unified, geometry-resolved framework for absorption, resonance fluorescence, entanglement, and phase-space quasiprobability in Doppler-broadened four-level Rydberg atoms. Within a density-matrix formalism incorporating velocity averaging and dressed-state analysis, these observables are shown to constitute complementary projections of a common coherence-driven structure governed by multi-photon interference. We further introduce the Stratonovich-Weyl (SW) Wigner function as a phase-space representation that encodes both population and coherence contributions on equal footing. A direct comparison reveals a near one-to-one correspondence between SW quasiprobability structures and entanglement landscapes, with coherence-induced features such as avoided crossings and detuning-dependent ridges preserved across representations. Isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the same coherence geometry underlying entanglement negativity. Resonance fluorescence emerges as a thermally robust and experimentally accessible observable: unlike absorption, it preserves spectral structure under Doppler averaging and reliably tracks dressed-state dynamics and entanglement extrema. Strong-field dressing and propagation geometry control the redistribution of coherence across velocity classes, leading to characteristic spectral asymmetries and ridge formation. These results establish a direct link between phase-space structure, spectroscopic observables, and quantum correlations in thermal media. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, this framework provides an experimentally accessible route for entanglement characterization without eigenvalue reconstruction, enabling Doppler-resilient, fluorescence-based quantum sensing in warm Rydberg systems.
We present a unified, geometry-resolved framework for analyzing absorption, resonance fluorescence, entanglement negativity, and phase-space quasiprobability in Doppler-broadened four-level atomic vapor. Using a density-matrix formalism with thermal velocity averaging and exact dressed-state diagonalization, we show that these observables constitute complementary projections of a common coherence-driven phase-space structure governed by multiphoton interference. Central to this framework is the Stratonovich-Weyl (SW) Wigner function, which provides a unified phase-space representation incorporating both populations and coherences. Direct comparison reveals a near one-to-one correspondence between SW quasiprobability distributions and entanglement landscapes, with geometry-dependent features, including hyperbolic dispersion asymptotes and split resonance ridges, consistently preserved. Furthermore, isolating the Doppler-odd component yields an eigenvalue-free proxy that captures the coherence geometry underlying entanglement negativity, providing a non-invasive quantum correlation witness. At the same time, resonance fluorescence emerges as a thermally robust observable: unlike susceptibility-based absorption, its additive pole weighting preserves sharp Autler-Townes spectral features under strong driving. This robustness enables fluorescence to accurately track bright dressed states and entanglement extrema despite severe Doppler dephasing, establishing its dual role as a sensitive electrometry probe and correlation witness. By combining a coherence-resolved description with a Doppler-sensitive phase-space representation, the proposed framework offers an experimentally accessible, eigenvalue-free approach to quantum state characterization, enabling Doppler-resilient fluorescence-based quantum sensing and precision field electrometry in warm atomic media.
Rydberg atoms efficiently link photons between the radio-frequency (rf) and optical domains. They furnish a medium in which the presence of an rf field imprints on the transmission of a probe laser beam by altering the coherent coupling between atomic quantum states. The immutable atomic energy structure underpins quantum-metrological rf-field measurements and has driven intensive efforts to realize inherently self-calibrated sensing devices. Here, we investigate spectroscopic signatures owing to the quantization of atomic angular momentum. Using an electromagnetically induced transparency (EIT) sensing scheme, specific combinations of atomic terms are shown to give rise to universal, distinctive fingerprints in the detected optical fields upon rotating a linearly polarized rf field. Employing a dressed state picture, we identify two types of atomic angular momentum ladders that display strikingly disparate spectroscopic characteristics, including the distinctive absence or presence of a central spectral EIT peak. Our study adds important insights into the prospects of Rydberg atomic gases for quantum-metrological electric field characterization including polarimetry. In particular, it calls into question prevailing interpretations of SI-traceable Rydberg atom electrometers.
The propagation of a probe field through a four-level Y-type atomic system is described in the presence of two additional coherent radiation fields, namely, the control field and the coupling field. An expression for the probe response is derived analytically from the optical Bloch equations under steady state condition to study the absorptive properties of the system under probe field propagation through an ensemble of stationary atoms as well as in a Doppler broadened atomic vapor medium. The most striking result is the conversion of electromagnetically induced transparency (EIT) into electromagnetically induced absorption (EIA) as we start switching from weak probe regime to strong probe regime. The dependence of this conversion on residual Doppler averaging due to wavelength mismatch is also shown by choosing the coupling transition as a Rydberg transition.
While Rydberg-Rydberg interactions are essential for quantum nonlinear optics and quantum information processing, their role in microwave and radio-frequency sensing remains poorly understood. Here we experimentally investigate Rydberg interaction-induced nonlinearity in cold-atom Rydberg electromagnetically induced transparency (EIT). In a three-level EIT system, increasing photon-photon interactions produces nonlinear spectral broadening accompanied by resonance shifts, while a microwave-dressed four-level system exhibits pronounced nonlinear broadening without detectable spectral shifts. Our three-level data can be explained by a conditional superatom model, whereas our four-level observations are surprisingly captured by a simple dephasing model. Comparisons with three representative models provide key insights to the role of many-body interactions in Rydberg EIT spectroscopy. Furthermore, our results clarify the conditions under which microwave field characterization can be performed in the nonlinear regime without introducing systematic bias. Our study advances both fundamental understanding of many-body physics and practical development of atomic sensors.