arXiv subjects

M. S. Ateto

Publications and source records attributed to M. S. Ateto.

5 recordsLinked to original sources

arXiv2026

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

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.

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arXiv2011

Topological Berry phase of a pumped three-level atom in the presence of dispersing and absorbing dielectric bodies: application to a half-space dielectric surface

Within the framework of exact quantum electrodynamics in dielectric, we study the topological Berry phase of a classically pumped $Λ$-type three-level atom, prepared initially in a superposition of its two pumped levels and located near a planar dielectric half-space with model permittivity of Lorentz type, interacts with a vacuum field. The effects of material losses, expressed in terms of the Green tensor of the dielectric-matter formation including dispersion and absorption, on the topological Berry phase of the photon transition between the pumped levels have been studied. The outcomes are compared with that of an atom in free space. We expect, the additional noise due to presence of the dielectric will modify, in a unified way, the behavior and values measured of the phase shift between the wavefunction evolution and its original state. It is shown that for small separation distance between atom and the dielectric surface, the angle separation between the wavefunction evolution and the original state reduced noticeably that is of strong applications in construction of the universal quantum logic gates. Further, the study opens routes for new challenging applications of atomically systems as various sources of coherent light emitted by pumped atoms in dielectric surroundings.

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arXiv2010

Entanglement Dynamics and Spin Squeezing of The non-linear Tavis-Cummings model mediated by a Nonlinear Binomial Field

We show that spin squeezing implies entanglement for quantum tripartite-state, where the subsystem of the bipartite-state is identical. We study the relation between spin squeezing parameters and entanglement through the quantum entropy of a system starts initially in a pure state when the cavity is binomial. We show that spin squeezing can be a convenient tool to give some insight into the subsystems entanglement dynamics when the bipartite subsystem interacts simultaneously with the cavity field subsystem, specially when the interaction occurs off-resonantly without and with a nonlinear medium contained in the cavity field subsystem. We illustrate that, in case of large off-resonance interaction, spin squeezing clarifies the properties of entanglement almost with full success. However, it is not a general rule when the cavity is assumed to be filled with a non-linear medium. In this case, we illustrate that the insight into entanglement dynamics becomes more clearly in case of a weak nonlinear medium than in strong nonlinear medium. In parallel, the role of the phase space distribution in quantifying entanglement is also studied. The numerical results of Husimi $Q$-function show that the integer strength of the nonlinear medium produces Schrödinger cat states which is necessary for quantum entanglement.

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arXiv2010

An investigation of a nonlocal entanglement of two uncoupled atoms embedded in a coherent cavity field and the associated phase space distribution: one quantum non-linear process

Entanglement properties of two uncoupled atoms embedded in a coherent field distribution through one quantum transition process is studied. A case of non-linear Hamiltonian of the problem is considered through which the effect of a non-linear media is illustrated. Moreover, the effect of the frequency difference between the interatomic transition and the electromagnetic field is also analyzed. We show that, adjusting the considered parametres of the non-linear media and frequency difference leads to a strong control of the degree of entanglement where excellent periodicity of entanglement evolution can be obtained which is very important in predicting the behavior of transmitted information through the application of various information processing schemes. We present a detailed and comparative study of atom-atom entanglement for two cases corresponding to different injections of the two atoms into the cavity field. Moreover, we present an answer to the question: How does the quantum phase space structure for a composite system relate to the entanglement characteristics of the corresponding quantum system? We demonstrate how the entanglement in nonlinear tripartite systems can be associated with a delocalization in the phase space distribution.

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arXiv2008

Control of a nonlocal entanglement in the micromaser via two quanta non-linear processes induced by dynamic Stark shift

We show that, under certain conditions, the micromaser can act as an effective source of highly correlated atoms. It is possible to create an extended robust entanglement between two successive, initially unentangled atoms passing through a cavity filled with with a nonlinear medium taking into consideration a slight level shift. Information is transfered from the cavity to the atoms in order to build up entanglement. The scheme has an advantage over conventional creation of entanglement if the two atoms (qubits) are so far apart that a direct interaction is difficult to achieve. The interaction of the atoms with the micromaser occurs under the influence of a two-quantum transition process. Interesting phenomena are observed, and an extended robust entangled state is obtained for different values of the system parameters. Illustrative variational calculations are performed to demonstrate the effect within an analytically tractable two-qubit model.

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