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Wave-particle duality in tripartite systems
(2023)
Quantum objects, sometimes called quantons, often display a characteristic feature that is referred to as wave-particle duality (WPD). Lately, this and other quantum traits have been submitted to intensive research, mainly motivated by the development of quantum information science. As a consequence, the scope of some concepts have been extended and it has been realized that they are not in the exclusive domain of quantum physics. This is particularly clear in optics, where qubits may show up as Jones vectors and WPD has its counterpart as wave-ray duality. WPD was originally addressed by focussing on a single qubit, which was afterwards supplemented with a second one playing the role of a path-marker in an interferometric setup. Fringe contrast, a sign of wavelike behavior, was proved to be diminished in connection with the e ectiveness of the marker, the inducer of particle-like behavior. Going from bipartite to tripartite states is a natural and necessary step towards a better understanding of WPD. This step is what we have accomplished in this work. We report some constraints ruling WPD for tripartite systems, as well as their experimental display with single photons.
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Laser spot measurement using simple devices
(American Institute of Physics Inc., 2021-07-01)
We have designed and tested an automated simple setup for measuring the profile and spot size of a Gaussian laser beam, which exhibits a similar performance to ready-made optical devices, using three light sensors. We use a light dependent resistor as a novel instrument in this approach with good accuracy. We provide the setup in detail in order to be reproduced with the current technology at a standard laboratory. Two profiling techniques were implemented: the imaging technique for the CMOS 2D array (webcam) and scanning knife-edge-like technique using a single photodiode and a light dependent resistor. We apply up-to-date devices, such as a Raspberry Pi, for automation. The methods and sensors were compared to determine their accuracy using lasers of two different wavelengths and technologies. We verify that it is possible to use a webcam to determine the profile of a laser with 1% uncertainty on the beam waist, 1.5% error on the waistline position, and less than 3% error in determining the minimum spot radius. We show that it is possible to use a light dependent resistor to estimate the laser spot size with an 11% error. The photodiode measurement is the most stable since it is not affected by the change in laser intensity.
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Measurement of charged-current $ν_μ$ and $\barν_μ$ cross sections on hydrocarbon in a shallow inelastic scattering region
(Cornell University, 2025-03-25)
This MINERvA analysis is the first neutrino and antineutrino study of a shallow inelastic scattering region, which is the transition region between resonant production and deep inelastic scattering processes. This transition is explicitly included in this study by expanding the scope of shallow inelastic scattering to include not only the mainly lower-$Q^2$ nonresonant pion production but also the kinematic region where pion production off quarks within the nucleon becomes significant with $Q^2$ below the onset of the deep-inelastic scattering region defined in this analysis. To reduce the resonance background the kinematic region 1.5 $<$ $W$ $<$ 2 GeV/$c^2$ was chosen. In addition to the inclusive differential cross section measurements, to emphasize SIS interactions off quarks within the nucleon a sample with $Q^2$ $\geq$ 1 GeV/$c^2$ was also analyzed. The measurements of one-dimensional cross sections at $\left\langle E_ν\right\rangle \sim 6$ GeV on hydrocarbon of $Q^2$, Bjorken x and muon momentum variables are compared with modified predictions from the GENIE 2 neutrino generator as well as predictions of other neutrino simulators GiBUU, NEUT, NuWro and an alternative GENIE 3 version. Significant discrepancies both in shape and magnitude between measurements and neutrino simulator predictions of all variables have been observed.
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Thermally Tunable Bi-Functional Metasurface Based on InSb for Terahertz Applications
(Multidisciplinary Digital Publishing Institute (MDPI), 2025)
In this work, we propose and analyze a thermally tunable metasurface based on indium antimonide (InSb), designed to operate in the terahertz (THz) frequency range. The metasurface exhibits dual functionalities: single-band perfect absorption and efficient polarization conversion, enabled by the temperature-dependent permittivity of InSb. At approximately 280 K, InSb transitions into a metallic state, enabling the metasurface to achieve near-unity absorptance (100%) at 0.408 THz under normal incidence, independent of polarization. Conversely, when InSb behaves as a dielectric at 200 K, the metasurface operates as an efficient polarization converter. By exploiting structural anisotropy, it achieves a polarization conversion ratio exceeding 85% over the frequency range from 0.56 to 0.93 THz, while maintaining stable performance for incident angles up to 45°. Parametric analyses show that the resonance frequency and absorption intensity can be effectively tuned by varying the InSb square size and the silica (SiO₂) layer thickness, achieving maximum absorptance at a SiO₂ thickness of 16 μm. The proposed tunable metasurface offers significant potential for applications in THz sensing, imaging, filtering, and wavefront engineering.
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Noninvasive Sonic Tomography for the Detection of Internal Defects in Relict Woodlands of Polylepis in Peru
(Multidisciplinary Digital Publishing Institute (MDPI), 2025)
Polylepis woodlands, endemic to the Andean Mountains, are critical for biodiversity and ecosystem services but face threats from anthropogenic disturbances and climate change. This study employed sonic tomography (ST) to assess the structural integrity of three relict Polylepis stands on the western slopes of the Peruvian Andes. A total of 192 tomograms from 48 trees across three sites revealed substantial variation in internal decay (2.5–70%), with mean decay levels of 11.6% (Z1), 16.6% (Z2), and 10.5% (Z3). Although the initial generalized linear mixed models (GLMMs) suggested tree diameters at breast height (DBH) as a potential predictor of decay, subsequent non-parametric Spearman’s correlation analysis found no significant relationship between DBH and decay (r < 0.001, p > 0.05) or between altitude and decay (r = 0.187, p = 0.204). No significant differences were detected among species or zones. The study demonstrates the efficacy of ST for noninvasive health assessment in high-altitude ecosystems and underscores the need for long-term monitoring to guide conservation strategies.
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Measurement of the inclusive isolated-photon production cross section in pp and Pb–Pb collisions at √ˢɴɴ=5.02 TeV
(Springer Nature, 2025)
The ALICE Collaboration at the CERN LHC has measured the inclusive production cross section of isolated photons at midrapidity as a function of the photon transverse momentum ( Pʸᴛ ), in Pb–Pb collisions in different centrality intervals, and in pp collisions, at centre-of-momentum energy per nucleon pair of √ˢɴɴ = 5.02 TeV. The photon transverse momentum range is between 10–14 and 40–140 GeV/c , depending on the collision system and on the Pb–Pb centrality class. The result extends to lower Pʸᴛ than previously published results by the ATLAS and CMS experiments at the same collision energy. The covered pseudorapidity range is |ηʸ| < 0.67 . The isolation selection is based on a charged particle isolation momentum threshold Pⁱˢᵒ′ᶜʰᴛ = 1.5 GeV/c within a cone of radii R = 0.2 and 0.4. The nuclear modification factor is calculated and found to be consistent with unity in all centrality classes, and also consistent with the HG-PYTHIA model, which describes the event selection and geometry biases that affect the centrality determination in peripheral Pb–Pb collisions. The measurement is compared to next-to-leading order perturbative QCD calculations and to the measurements of isolated photons and Z⁰ bosons from the CMS experiment, which are all found to be in agreement.
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Nonlinearity parameter estimation method from fundamental band signal depletion in pulse-echo using a dual-energy model
(Acoustical Society of America, 2025)
The estimation of the nonlinearity parameter (B/A) has the potential to be used in the clinical diagnosis of conditions such as liver steatosis. Recently, a pulse-echo method to estimate B/A based on the theory of the fundamental band amplitude depletion of weak waves, namely, the depletion method, was proposed. In the present work, the depletion method is presented with more technical detail. Then, the robustness of the depletion method is assessed by using simulations that diverge from the model requirements: (1) monochromatic plane wave propagation and (2) quadratic power-law frequency dependence attenuation. Regarding requirement (1), the results led to a critical finding that when using wideband pulses (37%–113% bandwidth), the bias of the B/A estimates is larger than the bias obtained using narrowband pulses (11%–28% bandwidth), even if requirement (2) holds. Regarding requirement (2), power-law frequency dependence closer to those of soft tissues, i.e., 1.1 or 1.2, using narrowband pulses presented bias of less than 10%. The use of narrowband pulses also was shown to be robust when the reference phantom and sample had attenuation mismatches of around 60%. Finally, the experimental feasibility of the depletion method was evaluated, showing results with good accuracy (bias <17%), which are consistent with the observations in the simulations.
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Spatially Weighted Fidelity and Regularization Terms for Attenuation Imaging
(Institute of Electrical and Electronics Engineers Inc., 2025)
Quantitative ultrasound (QUS) holds promise in enhancing diagnostic accuracy. For attenuation imaging, the regularized spectral log difference (RSLD) can generate accurate local attenuation maps. However, the performance of the method degrades when significant changes in backscatter amplitude occur. Variations in the technique were introduced involving a weighted approach to backscatter regularization, which, however, is not effective when changes in both attenuation and backscatter are present. This study introduces a novel approach that incorporates an L1-norm for backscatter regularization and spatially varying weights for both fidelity and regularization terms. The weights are calculated from an initial estimation of backscatter changes. Comparative analyses with simulated, phantom, and clinical data were performed. When changes in backscatter and attenuation occur, the proposed approach reduced the lowest root mean square error by up to 73%. It also improved the contrast-to-noise ratio (CNR) by a factor of 4.4 on average compared with previously available methods, considering the simulated and phantom data. In vivo results from healthy livers, thyroid nodules, and a breast tumor further confirm its effectiveness. In the liver, it is shown to be effective at reducing artifacts of attenuation images. In thyroid and breast tumors, the method demonstrated an enhanced CNR and better consistency of the attenuation measurements with the posterior acoustic enhancement. Overall, this approach offers promise for enhancing ultrasound attenuation imaging by helping differentiate tissue characteristics that may indicate pathology.
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Multi-Frequency Regularized Approach for Simultaneous Estimation of the Acoustic Nonlinearity Parameter and Attenuation Coefficient
(IEEE Computer Society, 2025)
The acoustic nonlinearity parameter (B/A) could enhance conventional ultrasound diagnostics in diseases associated with changes in fat tissue content. Recently, a simultaneous estimator of the B/A and the attenuation coefficient (AC) in pulse-echo was introduced, which was based on fitting measurements derived from backscattered data from a dual-energy model to a nonlinear model using the Gauss-Newton Levenberg-Marquardt algorithm (GNLM). However, the GNLM algorithm presented high sensitivity to the initial guess values. This paper improves the Gauss-Newton method by using data from several tone-burst transmissions at different center frequencies rather than only one narrowband tone-burst. In addition, it is combined with a total variation regularization approach (GNTV). The results in simulated and experimental phantoms suggest that incorporating regularization and increasing the number of transmission frequencies improves robustness compared to the GNLM method by accurately estimating B/A values (mean relative error less than 13% in the experiments).
1
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Revisiting the optoelectronic properties of sputtered aluminium-doped zinc oxide: a study combining advanced optical dispersion models
(Institute of Physics, 2025)
Aluminium-doped zinc oxide (AZO) thin films with different aluminium (Al) concentrations were grown by RF-magnetron sputtering with substrate active cooling. Sputtering induced sample heating was aimed to be mitigated by the applied cooling, achieving films with electrical resistivities as low as 3.3 × 10 − 3 Ω ⋅ cm , in the as-deposited state. Subsequently, an annealing treatment was performed to enhance the electrical properties and assess the effect of the Al concentration. The absorption coefficient spectra of zinc oxide (ZnO) exhibits an excitonic absorption contribution to the fundamental absorption that is typically not considered in AZO when determining the optical bandgap. Nevertheless, here we show that this free exciton band remains visible in AZO even at Al concentrations greater than 4 at.%. Additionally, the doping-induced defect states increases the width of tail states. These two factors have a substantial effect on the absorption edge, and thus must be considered with adequate models when attempting to determine the optical bandgap. In this work, we use a recently developed Elliot-based optical dispersion model to accurately determine the optical bandgap, exciton binding energy and Urbach energy of AZO thin films. On the other hand, we assess the infrared free carrier absorption, typically modeled by the Drude dispersion formula, by considering a complex frequency-dependent dynamical resistivity and the polar nature of the ZnO lattice. Normally, the real part of the dynamical resistivity follows a power law dependence and the exponent is assumed to be −1.5 for highly-doped semiconductors. Notwithstanding, here we let this exponent as a free fitting parameter to assess the effect of distinct scattering mechanisms present in sputtered AZO thin films and its dependence with the Al doping concentration. We believe these results can be extended to other degenerated semiconductors and are relevant for the understanding and tailoring of their fundamental optoelectronic properties.
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