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Graciana Puentes

Publications and source records attributed to Graciana Puentes.

At least 19 recordsLinked to original sources

Deterministic Mapping of Topological Phases via Autoregressive Exogenous Neural Networks

We report a comparative analysis of three dynamic neural network (NN) architectures -- NAR, NARX, and NIO -- to evaluate their efficiency in estimating the critical-measurement-strength parameter ($c_{crit}$) characterizing topological phase transitions in geometric phases induced by weak measurements. Our results demonstrate that the NARX architecture achieves superior predictive fidelity, reaching a Mean Squared Error (MSE) of $10^{-27}$ -- the limit of numerical precision -- at an optimal delay of $d=1$. This exceptional performance implies the identification of a perfect functional identity, suggesting that the relationship between winding numbers $W$ and $c_{crit}$ is mathematically deterministic. We observe a "complexity paradox" where the NARX model's accuracy collapses at higher delays ($d=4$), a phase-sensitivity that confirms the model captures a high-precision dynamic mapping rather than a trivial pattern. While the NAR model remains robust for local-trend capture, the NIO architecture fails to accurately resolve the phase transition despite increased neuronal capacity. These findings underscore that both autoregressive feedback and immediate exogenous context are essential for the exact characterization of topological phases, establishing NARX as a robust framework for deriving governing laws in complex quantum systems, where analytical solutions remain elusive.

quant-ph↗

A performance evaluation of integrating machine learning schemes utilizing fluidic lenses

A combination of statistical inference and machine learning (ML) schemes has been utilized to create a thorough understanding of coarse experimental data based on Zernike variables characterizing optical aberrations in fluidic lenses. A classification of surplus-response variables through tolerance manipulation was included to unravel the dimensional aspect of the data. Similarly, the impact of the exclusion of supererogatory variables through the identification of clustering movements of constituents is examined. The method of constructing a spectrum of collaborative results through the application of similar techniques has been tested. To evaluate the suitability of each statistical method before its application on a large dataset, a selection of ML schemes has been proposed. The supervised learning tools principal component analysis (PCA), factor analysis (FA), and hierarchical clustering (HC) were employed to define the elemental characteristics of Zernike variables. PCA enabled to reduce the dimensionality of the system by identifying two principal components which collectively account for 95\% of the total variance. The execution of FA indicated that a specific tolerance of independent variability of 0.005 could be used to reduce the dimensionality of the system without losing essential data information. A high cophenetic coefficient value of c=0.9629 validated an accurate clustering division of variables with similar characteristics. The current approach of mutually validating ML and statistical analysis methods will aid in laying the foundation for state-of-the-art (SOTA) analysis. The benefit of our approach can be assessed by considering that the associated SOTA will enhance the predictive accuracy between two comparable methods, in contrast to the SOTA analysis conducted between two arbitrary ML methods.

physics.optics↗

Comparison between neural network clustering, hierarchical clustering and k-means clustering: Applications using fluidic lenses

A comparison between neural network clustering (NNC), hierarchical clustering (HC) and K-means clustering (KMC) is performed to evaluate the computational superiority of these three machine learning (ML) techniques for organizing large datasets into clusters. For NNC, a self-organizing map (SOM) training was applied to a collection of wavefront sensor reconstructions, decomposed in terms of 15 Zernike coefficients, characterizing the optical aberrations of the phase front transmitted by fluidic lenses. In order to understand the distribution and structure of the 15 Zernike variables within an input space, SOM-neighboring weight distances, SOM-sample hits, SOM-weight positions and SOM-weight planes were analyzed to form a visual interpretation of the system's structural properties. In the case of HC, the data was partitioned using a combined dissimilarity-linkage matrix computation. The effectiveness of this method was confirmed by a high cophenetic correlation coefficient value (c=0.9651). Additionally, a maximum number of clusters was established by setting an inconsistency cutoff of 0.8, yielding a total of 7 clusters for system segmentation. In addition, a KMC approach was employed to establish a quantitative measure of clustering segmentation efficiency, obtaining a sillhoute average value of 0.905 for data segmentation into K=5 non-overlapping clusters. On the other hand, the NNC analysis revealed that the 15 variables could be characterized through the collective influence of 8 clusters. It was established that the formation of clusters through the combined linkage and dissimilarity algorithms of HC alongside KMC is a more dependable clustering solution than separate assessment via NNC or HC, where altering the SOM size or inconsistency cutoff can lead to completely new clustering configurations.

physics.optics↗

Topological weak-measurement-induced geometric phases revisited

We present an analytical and numerical study of a class of geometric phase induced by weak measurements. In particular, we analyze the dependence of the geometric phase on the winding ($W$) of the polar angle ($φ$), upon a sequence of $N$ weak measurements of increased magnitude ($c$), resulting in the appearance of a multiplicity of critical measurement-strength parameters where the geometric phase becomes stochastic. Adding to the novelty of our approach, we not only analyze the weak-measurement induced geometric phase by a full analytic derivation, valid in the quasicontinuous limit ($N \rightarrow \infty$), but also we analyze the induced geometric phase numerically, thus enabling us to unravel the finite-$N$ interplay of the geometric phase with the measurement strength parameter, and its stability to perturbations in the measurements protocol.

quant-ph↗

Spectral Characterization of Optical Aberrations in Fluidic Lenses

We report an extensive numerical study and supporting experimental results on the spectral characterization of optical aberrations in macroscopic fluidic lenses with tunable focal distance and aperture shape. Using a Shack-Hartmann wave-front sensor we experimentally reconstruct the near-field wave-front transmitted by the fluidic lenses, and we characterize the chromatic aberrations in terms of Zernike polynomials in the visible range. Moreover, we further classify the spectral response of the lenses using clustering techniques, in addition to correlation and convolution measurements. Experimental results are in agreement with our theoretical model of the non-linear deformation of thin elastic membranes.

physics.optics↗

2D Zak Phase Landscape in Photonic Discrete-Time Quantum Walks

We present a study of the 2D Zak phase landscape in photonic discrete-time quantum walk (DTQW) protocols. In particular, we report numerical results for three different DTQW scenarios which preserve spatial inversion symmetry (SIS) and time-reversal symmetry (TRS), while presenting a non-trivial Zak phase structure, as a consequence of a non-vanishing Berry connection. Additionally, we propose a novel approach to break TRS in photonic systems, while preserving a vanishing Berry curvature. Our results bear a close analogy to the Aharonov-Bohm effect, stating that in a field-free multiply connected region of space the evolution of the system depends on vector potentials, due to the fact that the underlying canonical formalism cannot be expressed in terms of fields alone.

quant-ph↗

Spin-Orbit Interactions of Light: Fundamentals and Emergent Applications

We present a comprehensive review of recent developments in Spin Orbit Interactions (SOIs) of light in photonic materials. In particular, we highlight progress on detection of Spin Hall Effect (SHE) of light in hyperbolic metamaterials and metasurfaces. Moreover, we outline some fascinating future directions for emergent applications of SOIs of light in photonic devices of the upcoming generation.

physics.optics↗

High-Dimensional Entanglement of Photonic Angular Qudits

We propose a method for generation of entangled photonic states in high dimensions, the so-called qudits, by exploiting quantum correlations of Orbital Angular Momentum (OAM) entangled photons, produced via Spontaneous Parametric Down Conversion. Diffraction masks containing $N$ angular slits placed in the path of twin photons define a qudit space of dimension $N^2$, spanned by the alternative pathways of OAM-entangled photons. We quantify the high-dimensional entanglement of path-entangled photons by the Concurrence, using an analytic expression valid for pure states. We report numerical results for the Concurrence as a function of the angular aperture size for the case of high-dimensional OAM entanglement and for the case of high-dimensional path entanglement, produced by $N \times M$ angular slits. Our results provide additional means for preparation and characterization of entangled quantum states in high-dimensions, a fundamental resource for quantum simulation and quantum information protocols.

quant-ph↗

Deterministic Preparation of Non-Gaussian Quantum States: Applications in Quantum Information Protocols

We report a scheme for deterministic preparation of non-Gaussian quantum states on-demand. In contrast to probabilistic approaches for preparation of non-Gaussian quantum states, conditioned on photon subtraction or addition, we present a scheme that can prepare non-Gaussian quantum states on-demand, by applying a unitary transformation which removes the Gaussianity of measurement statistics of field quadratures, namely a quadrature rotation via transmission through a beam-splitter, using a two-mode photon-number squeezed state as input. The resulting state exhibits a quantum vortex structure in quadrature space, confirming its non-Gaussian nature. Such non-Gaussian quantum state also reveals increased entanglement content, as quantified by the Logarithmic Negativity and the Wigner function negative volume, therefore displaying high potential for applications in quantum information protocols, in particular for applications in entanglement distillation schemes.

quant-ph↗

Generation of High-Order Vortex States from Two-Mode Squeezed States

We report a scheme for generation of high-order vortex states using two-mode photon-number squeezed states, generated via the non-linear process of Spontaneous Parametric Down Conversion. By applying a parametric rotation in quadrature space $(X,Y)$, using a $ϕ$ converter, the Gaussian quadrature profile of the photon-number squeezed input state can be mapped into a superposition of Laguerre-Gauss modes with $N$ vortices or singularities, for an input state containing $N$ photons, thus mapping photon-number fluctuations to interference effects in quadrature space. Our scheme has the potential to improve measurement sensitivity beyond the Standard Quantum Limit (SQL $\propto \sqrt{N}$), by exploiting the advantages of optical vortices, such as ease of creation and detection, high dimensionality or topological properties, for applications requiring reduced uncertainty, such as quantum cryptography, quantum metrology and sensing.

quant-ph↗

High-dimensional Angular Two-Photon Interference and Angular Qudit States

Using angular position-orbital angular momentum entangled photons, we propose an experiment to generate maximally entangled states of $D$-dimensional quantum systems, the so called qudits, by exploiting correlations of parametric down-converted photons. Angular diffraction masks containing $N$-slits in the arms of each twin photon define a qudit space of dimension $N^2$, spanned by the alternative pathways of the photons. Due to phase-matching conditions, the twin photons will pass only by symmetrically opposite angular slits, generating maximally entangled states between these different paths, which can be detected by high-order two-photon interference fringes via coincidence counts. Numerical results for $N$ angular slits with $N = 2, 4, 5, 6, 10$ are reported, corresponding to qudit Hilbert spaces of dimension $D=N^2=4,16,25, 36,100$, respectively. We discuss relevant experimental parameters for an experimental implementation of the proposed scheme using Spatial Light Modulators (SLMs), and twin-photons produced by Spontaneouos Parametric Down Conversion (SPDC). The entanglement of the qudit state can be quantified in terms of the Concurrence, which can be expressed in terms of the visibility of the interference fringes, or by using Entanglement Witnesses. These results provide an additional means for preparing entangled quantum states in high-dimensions, a fundamental resource for quantum simulation and quantum information protocols.

quant-ph↗

Photonic Discrete-time Quantum Walks and Applications

We present a review of photonic implementations of discrete-time quantum walks (DTQW) in the spatial and temporal domains, based on spatial- and time-multiplexing techniques, respectively. Additionally, we propose a detailed novel scheme for photonic DTQW, using transverse spatial modes of single photons and programmable spatial light modulators (SLM) to manipulate them. Unlike all previous mode-multiplexed implementations, this scheme enables simulation of an arbitrary step of the walker, only limited, in principle, by the SLM resolution. We discuss current applications of such photonic DTQW architectures in quantum simulation of topological effects and the use of non-local coin operations based on two-photon hybrid entanglement.

quant-ph↗

Spin-Orbit Angular Momentum Conversion in Metamaterials and Metasurfaces

In the last decades unprecedented progress in the manipulation of spin angular momentum (SAM) and orbital angular momentum (OAM) of light has been achieved, enabling a number of applications ranging from classical and quantum communication, to optical microscopy and super-resolution imaging. Metasurfaces are artificially engineered 2D metamaterials with designed subwavelength-size building blocks, which allow precise control of optical fields with unparalleled flexibility and performance. The reduced dimensionality of optical metasurfaces enables new physics and leads to functionalities and applications that are remarkably different from those achievable with bulk materials. In this review, we present an overview of the progress in optical metasurfaces for manipultation of SAM and OAM of light, for applications in integrated spin-orbit conversion (SOC) devices.

physics.optics↗

Observation of two-beam collective scattering phenomena in a Bose-Einstein condensate

New phenomena of collective light scattering are observed when an elongated Bose-Einstein condensate is pumped by two non-interfering beams counterpropagating along its long axis. In the limit of small Rayleigh scattering rates, the presence of a second pump beam suppresses superradiance, whereas at large Rayleigh scattering rates it lowers the effective threshold power for collective light scattering. In the latter regime, the quench dynamics of the two-beam system are oscillatory, compared to monotonic in the single-beam case. In addition, the dependence on power, detuning, and atom number is explored. The observed features of the two-beam system qualitatively agree with the recent prediction of a supersolid crystalline phase of light and matter at large Rayleigh scattering rates [S. Ostermann, F. Piazza, and H. Ritsch, Phys. Rev. X 6, 021026 (2016).]

cond-mat.quant-gas↗

Photonic spin Hall effect in hyperbolic metamaterials at visible

Photonic spin Hall effect in transmission is a transverse beam shift of the out-coming beam depending on polarization of the in-coming beam. The effect can be significantly enhanced by materials with high anisotropy. We report the first experimental demonstration of the photonic spin Hall effect in a multilayer hyperbolic metamaterial at visible wavelengths (wavelengths of 520 nm and 633 nm). The metamaterial is composed of alternating layers of gold and alumina with deeply-subwavelength thicknesses, exhibiting extremely large anisotropy. The angle resolved polarimetric measurements showed the shift of 165 $μm$ for the metamaterial of 176 nm in thickness. Additionally the transverse beam shift is extremely sensitive to the variations of the incident angle changing theoretically by 270 $μm$ with one milli-radian ($0.057^\circ$). These features can lead to minituarized spin Hall switches and filters with high angular resolution.

physics.optics↗

Spin Hall effect and circular birefringence in polymers

We demonstrate experimentally the fine lateral circular birefringence of a tunable birefringent polymer, the first example of the spin Hall effect of light in a polymeric material. We report experimental observations of this effect using polarimetric techniques and quantum-weak-measurement techniques, reporting a weak amplification factor of 200.

physics.optics↗

Tunable Fluidic Lenses with High Dioptric Power for Impaired Vision

We report experimental and theoretical results on the production of macroscopic fluidic lenses with high dioptric power, tunable focal distance and aperture shape, for applications in adaptive eyewear for the sub-normal vision segment. The lense is 17 mm wide and is made of an elastic PDMS polymer, which can adaptively restore accommodation distance within several centimeters according to the fluidic volume mechanically pumped in. Moreover, the lens can provide for magnification in the range of +25 Diopter to +100 Diopter with optical aberrations on the order of the wave-length, and overall lens weight of less than 2 $g$. We argue that these features make the proposed lenses appropriate for the impaired vision segment.

physics.optics↗

Quantum Walk Topology and Spontaneous Parametric Down Conversion

In a recent detailed research program we proposed to study the complex physics of topological phases by an all optical implementation of a discrete-time quantum walk. The main novel ingredient proposed for this study is the use of non-linear parametric amplifiers in the network which could in turn be used to emulate intra-atomic interactions and thus analyze many-body effects in topological phases even when using light as the quantum walker. In this paper, and as a first step towards the implementation of our scheme, we analize the interplay between quantum walk lattice topology and spatial correlations of bi-photons produced by spontaneous parametric down-conversion. We also describe different detection methods suitable for our proposed experimental scheme.

quant-ph↗