Coherent Processing Research Articles

Linking Inca Terraces with Landslide Occurrence in the Ticsani Valley, Peru

Since the times of the Incas, farmers in the remote Andes of Peru have constructed terraces to grow crops in a landscape characterized by steep slopes, semiarid climate, and landslide geohazards. Recent investigations have concluded that terracing and irrigation techniques could enhance landslide risk due to the increase in water percolation and interception of surface flow in unstable slopes, leading to failure. In this study, we generated an inventory of 170 landslides and terraced areas to assess the spatial coherence, causative relations, and geomechanical processes linking landslide presence and Inca terraces in a 250 km2 area located in the Ticsani valley, southern Peru. To assess spatial coherence, a tool was developed based on the confusion matrix approach. Performance parameters were quantified for areas close to the main rivers and communities yielding precision and recall values between 64% and 81%. On a larger scale, poor performance was obtained pointing to the existence of additional processes linked to landslide presence. To investigate the role of other natural variables in landslide prediction, a logistic regression analysis was performed. The results showed that terrace presence is a statistically relevant factor that bolsters landslide presence predictions, apart from first-order natural variables like distance to rivers, curvature, and geology. To explore potential geomechanical processes linking terraces and slope failures, FEM numerical modeling was conducted. Results suggested that both decreased permeability and increased surface irrigation, at 70% of the average annual rainfall, are capable of inducing slope failure. Overall, irrigated terraces appear to further promote slope instability due to infiltration of irrigation water in an area characterized by fluvial erosion, high relief, and poor geologic materials, exposing local communities to increased landslide risk.

A new class of non-linear filtering and windowing methods for coherent image processing and reconstruction

A new class of non-linear filtering and windowing methods for coherent image processing and reconstruction

Multiple-In-One Photonic Integrated Transceiver for Multi-Chirp-Rate & Multi-Band ISAR System and Coherent Fusion Processing

Multiple-In-One Photonic Integrated Transceiver for Multi-Chirp-Rate & Multi-Band ISAR System and Coherent Fusion Processing

Language, Theory of Mind and Cognitive skills in Arabic-speaking children with and without autism: Evidence from network and cluster analyses

IntroductionAutism spectrum disorder (ASD) is characterized by impairments in social interactions, social communication, and repetitive and stereotyped patterns of behavior. Previous studies have reported mixed findings regarding the links between language (i.e., phonology, morphosyntax, lexicon and pragmatics), theory of mind (ToM), executive functions (EFs), and central coherence measures in children with ASD. MethodsA total of 163 Palestinian-Arabic-speaking children aged 4-11 participated: 76 with ASD and 87 with typical language development (TLD). The children`s phonological, morphosyntactic, lexical, and pragmatic skills and verbal and non-verbal ToM abilities were evaluated. Additionally, cognitive assessments included non-verbal IQ, EF, and central coherence processing. ResultsGroup-level results showed that children with ASD scored lower than their TLD peers in all measures. Network analysis revealed robust interconnections between language, ToM, and cognitive skills in both groups. In autistic children, language was a central node, with pragmatics prevailing over morphosyntax and lexicon, while age was central in the TLD group. Cluster analysis identified four language clusters within the ASD group, demonstrating dissociations between language domains: (1) high performance across all domains, (2) moderate performance in phonology and morphosyntax with low pragmatic abilities, (3) moderate performance in phonology and lexicon with low morphosyntax and pragmatics, and (4) moderate phonology and lexicon with extremely poor morphosyntax and pragmatics. Autistic children with enhanced language abilities performed better in verbal and non-verbal ToM and EF tasks. ConclusionsOur findings underscore the variability in language, ToM, and cognitive profiles of autistic children, showing dissociation within and between different domains in some autistic children. These results offer insights for applied interventions.

Schwinger vs Unruh (Mini-review)

It is shown that the temperatures which characterise the Unruh effect, the Gibbons-Hawking radiation from the de Sitter cosmological horizon and the Hawking radiation from the black hole horizon acquire the extra factor 2 compared with their traditional values. The reason for that is the coherence of different processes. The combination of the coherent processes also allows us to make the connection between the Schwinger pair production and the Unruh effect.

Multiple-Input Multiple-Output Microwave Tomographic Imaging for Distributed Photonic Radar Network

This paper deals with the imaging problem from data collected by means of a microwave photonics-based distributed radar network. The radar network is leveraged on a centralized architecture, which is composed of one central unit (CU) and two transmitting and receiving dual-band remote radar peripherals (RPs), it is capable of collecting monostatic and multistatic phase-coherent data. The imaging is herein formulated as a linear inverse scattering problem and solved in a regularized way through the truncated singular value decomposition inversion scheme. Specifically, two different imaging schemes based on an incoherent fusion of the tomographic images or a fully coherent data processing are herein developed and compared. Experimental tests carried out in a port scenario for imaging both a stationary and a moving target are reported to validate the imaging approach.

Adding value for clients during work disability assessments: A qualitative exploration from the perspective of medical examiners.

Value-based healthcare delivery focuses on optimizing care provided by measuring the healthcare outcomes which are most important to the clients relative to the total care costs. However, the understanding of what adds value for clients during work disability assessment is lacking. To explore what medical examiners (MEs) perceive as valuable during the work disability assessment process, by exploring possible: 1) facilitators, 2) barriers and 3) opportunities to add value for the client during the work disability assessment. For this explorative qualitative study, 7 semi-structured interviews were conducted with MEs in the Netherlands. Thematic coding was performed for all interviews. A large variety of facilitators (n = 22), barriers (n = 17) and opportunities (n = 11) were identified and inductively subdivided into four main themes: 1) coherent process, including all time related aspects, 2) interdisciplinary collaboration, including all aspects related to the collaboration between the ME and other professionals, 3) client-centred interaction, including all aspects related to the supportive interplay from the ME towards the client, and 4) information provision on all aspects during the work disability assessment process towards the client to ensure a valuable work disability assessment process. The overview of identified possible facilitators, barriers and opportunities to add value for clients from the perspective of the ME may stimulate improvement in the current work disability assessment practice and to better match the client needs.

Cross-Sections of Neutral-Current Neutrino Scattering on 94,96Mo Isotopes

In our recent publications, we presented neutral-current ν–nucleus cross-sections for the coherent and incoherent channels for some stable Mo isotopes, assuming a Mo detector medium, within the context of the deformed shell model. In these predictions, however, we have not included the contributions in the cross-sections stemming from the stable 94,96Mo isotopes (abundance of 94Mo 9.12% and of 96Mo 16.50%). The purpose of the present work is to perform detailed calculations of ν–94,96Mo scattering cross-sections, for a given energy Eν of the incoming neutrino, for coherent and incoherent processes. In many situations, the Eν values range from 15 to 30 MeV, and in the present work, we used Eν = 15 MeV. Mo as a detector material has been employed by the MOON neutrino and double-beta decay experiments and also from the NEMO neutrinoless double-beta decay experiment. For our cross-section calculations, we utilize the Donnelly–Walecka multipole decomposition method in which the ν–nucleus cross-sections are given as a function of the excitation energy of the target nucleus. Because only the coherent cross-section is measured by current experiments, it is worth estimating what portion of the total cross-section represents the measured coherent rate. This requires the knowledge of the incoherent cross-section, which is also calculated in the present work.

Numerical modeling of partially coherent anti-Stokes Raman scattering (pCARS) in transparent molecular liquids

In this study, the key characteristics of the so called partially coherent anti-Stokes Raman scattering (pCARS) are numerically modeled in order to explain the physical nature of this nonlinear Raman effect. The experimental data obtained by Ishibashi and Hamaguchi, the pioneer researchers of pCARS, are simulated by use of analytical description different from their original physical interpretation. The numerical results for the spatial distribution of the anti-Stokes Raman signal in pCARS, the shape of the pCARS spectral line, and the dependence of the pCARS signal intensity on the laser pulse intensity, as well as on the concentration and temperature of the Raman medium, all matching the pCARS experimental data, indicate a complex parametric-stimulated mechanism of generation/amplification of pCARS. The differences of pCARS from ordinary CARS (fully coherent process of Raman scattering) are highlighted.

From Periphery to Center: The Emotional Sequence of Cognitive Revision in L2 Writing Assessment.

Peripheral self-proofreading activities, such as grammatical correction, spelling checks, and word modifications, have traditionally been viewed as essential components of writing feedback. However, central revision tasks-including cognitive processing, critical thinking, and emotional sequencing-have received insufficient attention. These central revision activities are crucial for assessing the emotional flow of writing. This study seeks to explore central revision processes to uncover authentic issues faced during writing tasks. We analyzed the revision processes of 113 college students, aged 19 to 22, using Inputlog Version 6 software to evaluate emotional sequences based on 4,629 revision traces. The study revealed that emotional sequences in central revision could be identified through four key indicators: language proficiency, discourse coherence, perceptual pathway, and perceptual processing. We also observed that nuanced emotional sequences were associated with higher writing proficiency. These findings have significant implications for enhancing central revision practices in second language (L2) writing, aiming to improve the efficiency of writing revisions. They also provide valuable guidance for both educators and students, highlighting the importance of emotional sequencing in the writing process.

A novel energy-focused slow-time MIMO radar and signal processing scheme

In this paper, we propose a novel energy-focused slow-time MIMO radar and signal processing scheme, aimed at addressing key challenges in slow-time coding and signal processing technology. Conventional slow-time MIMO radar faces issues such as energy waste due to the omnidirectional transmit beampattern of orthogonal coding and the velocity ambiguity problem. To overcome these limitations, the proposed radar system utilizes a method based on Doppler frequency offset diversity (DFOD) for slow-time coding design. This method enables the adjustment of Doppler offset parameters to achieve a rectangular transmit beampattern with any mainlobe width within a single coherent processing interval (CPI), offering the advantage of low computational complexity. Through an analysis of the ambiguity function for DFOD-based coding, we evaluate both Doppler and angular resolution. To further improve Doppler frequency resolution, a slow-time coding design is introduced based on Pulse Random Permutation (PRP). Subsequently, a signal processing scheme based on matched filtering is presented. To tackle the high Doppler sidelobe issue associated with PRP-based coding, we propose a mismatch filter (MMF) design method utilizing convex optimization. Ultimately, the performance enhancement of the proposed slow-time MIMO radar is verified through simulation analysis in comparison to existing technologies.

Efficacy of Therapeutic Photography for Resolving Symptom Coherence in Prolonged Grief

Prolonged grief disorder (PGD) is a complex and debilitating condition that arises from the inability to adapt to the loss of a significant individual. Symptom coherence, meaning-making, and emotional processing are key symptom domains for individuals experiencing prolonged grief. The integration of photographic interventions within grief counseling practices offers a unique and powerful tool for emotional expression, emotional processing, and overall grief management. This literature review aims to synthesize current research on the efficacy of this innovative approach, primarily focusing on how photographic interventions impact symptom coherency, psychological healing mechanisms, and psychological healing.

An unsupervised coherent receiver digital signal processing algorithm based on spectral clustering with no data preamble

AbstractA coherent optical receiver digital signal processing (DSP) scheme is proposed based on spectral clustering, which utilises spectral clustering to cluster the signals outputted by the DSP. Compared to existing blind DSP algorithms for coherent optical receivers operating at over 100Gbps with PM‐mQAM, the proposed scheme effectively suppresses various physical impairments, achieving lower bit error rates (BERs) at the same transmission distance, thus enabling longer transmission distances under the same forward error correction threshold. Furthermore, simulations of the proposed scheme on a 14GBaud PM‐16QAM coherent optical transmission system show that, at a BER of 1.9E‐2, the maximum transmission distance increases from 1700 to 2000 km, and at a BER of 3.8E‐3, it increases from 700 to 900 km.

High-performance silicon photonic single-sideband modulators for cold-atom interferometry.

The laser system is the most complex component of a light-pulse atom interferometer (LPAI), controlling frequencies and intensities of multiple laser beams to configure quantum gravity and inertial sensors. Its main functions include cold-atom generation, state preparation, state-selective detection, and generating a coherent two-photon process for the light-pulse sequence. To achieve substantial miniaturization and ruggedization, we integrate key laser system functions onto a photonic integrated circuit. Our study focuses on a high-performance silicon photonic suppressed-carrier single-sideband (SC-SSB) modulator at 1560 nanometers, capable of dynamic frequency shifting within the LPAI. By independently controlling radio frequency (RF) channels, we achieve 30-decibel carrier suppression and unprecedented 47.8-decibel sideband suppression at peak conversion efficiency of -6.846 decibels (20.7%). We investigate imbalances in both amplitudes and phases between the RF signals. Using this modulator, we demonstrate cold-atom generation, state-selective detection, and atom interferometer fringes to estimate gravitational acceleration, g ≈ 9.77 ± 0.01 meters per second squared, in a rubidium (87Rb) atom system.

Ultrafast Dynamics of Bloch Surface Wave Polaritons in Large-Area 2D Semiconductor Monolayers at Room Temperature.

The dynamics of strongly coupled polariton systems integrated with 2D transition metal dichalcogenides (TMDs) is key to enabling efficient coherent processes and achieving high-performance TMD-based polaritonic devices, such as ultralow-threshold polariton lasers and ultrafast optical switches. However, there has been a lack of a comprehensive understanding of the excited state dynamics in TMD-based polariton systems. In this work, ultrafast pump-probe optical spectroscopy is used to investigate the room temperature dynamics of the polariton systems consisting of TMD monolayer excitons strongly coupled with Bloch surface waves (BSWs) supported by all-dielectric photonic structures. The transient response is found for both above-exciton energy pumping and polariton-resonant pumping. The excited state population and ultrafast coherent coupling of the exciton reservoir and lower polariton (LP) branch are observed for resonant pumping. Moreover, it is found that the transient response of the LP first decays on a short-time scale of 0.15-0.25ps compared to the calculated intrinsic lifetime of 0.11-0.20ps, and is followed by a longer decay (>100ps) due to the dynamical evolution of the exciton reservoir. The results provide a fundamental understanding of the dynamics of TMD-based polariton systems while showing the potential for achieving efficient coherent optical processes for device applications.

Transfer of optical vortices in a coherently-prepared rare-earth-ion-doped solid

Optical vortices carrying orbital angular momentum (OAM) of light have earned much attention due to their potential applications in the classical and quantum physics. Quantum coherence has been proved to be an important tool for controlling the behavior of light fields. Developing the manipulation method of optical vortices is very useful for high-dimensional information processing encoded with OAM. In this paper, we experimentally investigate the transfer of optical vortices between different light modes in a coherently-prepared solid-state medium. Utilizing the technique of fractional stimulated Raman passage (f-STIRAP), the experimental medium is prepared into a coherent superposition of two ground states. By applying a probe vortex beam to scatter the induced atomic coherence, a new signal is generated with the same vorticity as that of the input probe field. Furthermore, the vortex beams are used as the f-STIRAP preparation pulses, and the helical phases of the vortex beams are mapped into the coherent superposition state. Subsequently, the optical vortices of the preparation pulses are transferred to a new light mode by using the probe beam to interact with the coherent medium. The new signal field accumulates the total topological charges of the applied fields in this coherent process. Such an experimental demonstration will enrich the interactions between optical vortices and matter, and can be helpful in further information processing.

Theoretical Study for Spin Transport properties of FM-(G/C)10- FM

In the present study, we propose a physical model to study spin transport through DNA system and provide apparent physical mechanism for spin dependent phenomenon. The system considered in our work is DNA bases guanine-cytosine coupled to two ferromagnetic leads (FM-(G/C)10-FM) in parallel and anti-parallel configuration case, throughout magnetic quantum contacts. Our treatment is based on the tight binding model to derive obvious formula for the transmission spectrum which is employed to investigate the spin dependent current-bias voltage characteristics and the temperature - Conductance dependence. Our calculations of for strong, weak and without backbone regimes. Various factors are involved in our -study. These are the electrical contacts between DNA molecules and electrodes, the structure of DNA molecule and the environment around DNA molecule. The system spin dependent factors, that are investigated extensively in our study include the spin dependent coupling between subsystems, the quantum contacts between active region and electrodes, majority and minority electrons spin in the ferromagnetic leads as well as externally applied bias voltage. Variation of these factors can enhanced or suppressed spin transport through (G/C)10 molecule. The transmission spectrum calculations conform that the spin transport throughout (G/C)10 originates by a coherent tunneling process between neighboring bases through the overlapping of the LUMO orbitals of the bases. Our results showed that the spin-polarized transport that can be effectively regulated by the type of regime as well as the spin configuration in the leads which can exhibit efficient spin filtering and spin switching by employing the spin blockade phenomenon

Determining the number of small-sized radars in a network with coherent signal processing for the detection of stealth aerial vehicles

The object of this study is the process of determining the number of small-sized radars in the network when detecting stealth unmanned aerial vehicles. The main hypothesis of the study assumed that determining the optimal number of small-sized radars in the network will make it possible not to waste unnecessary resources of radars to detect stealth unmanned aerial vehicles. The main stages of detection of a stealth unmanned aerial vehicle by a network of small-sized radars are: – reception of the signal reflected from a stealth unmanned aerial vehicle by all small-sized radars of the network; – coordinated filtering of incoming signals in each small-sized radar; – compensation of phase shifts in each matched filter; – coherent addition of output signals from each matched filter at the output of the receivers of each of the N small-sized radars performing reception; – formation of a complex bypass at the output of the corresponding Doppler channel in each small-sized radar of the network; – coherent processing of signals from all elements of the network of small-sized radars; – detection of the output signal from the adder of coherent signals. At the same time, compensation for the random initial phase of signals reflected from a stealth unmanned aerial vehicle is also performed. It has been established that the increase in the elements of the network of small-sized radars increases the value of the conditional probability of correct detection. Such an increase is more significant when the number of elements in the network of small-sized radars is increased to two or three. The gain in the signal/noise ratio when adding elements to the network of small-sized radars was evaluated. It was established that the optimal number of small-sized radars in a network with coherent signal processing when detecting stealth unmanned aerial vehicles is 2‒3 radars

Sub-100-fs energy transfer in coenzyme NADH is a coherent process assisted by a charge-transfer state

Excitation energy transfer (EET) is a key photoinduced process in biological chromophoric assemblies. Here we investigate the factors which can drive EET into efficient ultrafast sub-ps regimes. We demonstrate how a coherent transport of electronic population could facilitate this in water solvated NADH coenzyme and uncover the role of an intermediate dark charge-transfer state. High temporal resolution ultrafast optical spectroscopy gives a 54±11 fs time constant for the EET process. Nonadiabatic quantum dynamical simulations computed through the time-evolution of multidimensional wavepackets suggest that the population transfer is mediated by photoexcited molecular vibrations due to strong coupling between the electronic states. The polar aqueous solvent environment leads to the active participation of a dark charge transfer state, accelerating the vibronically coherent EET process in favorably stacked conformers and solvent cavities. Our work demonstrates how the interplay of structural and environmental factors leads to diverse pathways for the EET process in flexible heterodimers and provides general insights relevant for coherent EET processes in stacked multichromophoric aggregates like DNA strands.

Mapping the magnon–magnon hybrid state onto the Bloch sphere

We investigate magnon–magnon hybrid states using a non-Hermitian Hamiltonian and the concept of magnon hybridization. By comparing our model with micromagnetic simulations conducted on a synthetic antiferromagnet with strong magnon–magnon coupling, the two-level model reproduces not only the resonance frequencies and linewidths but also the phases and amplitudes of the magnon eigenmode. The coherent coupling between magnons results in both the anticrossing of the energy spectra and the mixing of the linewidths. Specially, it forms a two-level system and makes the eigenmode of the hybrid state as a linear combination of the pure acoustic and optic modes. After that, we map the magnon–magnon hybrid state, including the magnon state of exceptional point, onto a Bloch sphere, which enhances the ability to manipulate hybrid magnons for coherent information processing.