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Sub-picosecond optical laser processing of metals is actively utilized for modification of a heated surface layer. But for deeper modification of different materials a laser in the hard x-ray range is required. Here, we demonstrate that a single 9-keV x-ray pulse from a free-electron laser can form a um-diameter cylindrical cavity with length of ~1 mm in LiF surrounded by shock-transformed material. The plasma-generated shock wave with TPa-level pressure results in damage, melting and polymorphic transformations of any material, including transparent and non-transparent to conventional optical lasers. Moreover, cylindrical shocks can be utilized to obtain a considerable amount of exotic high-pressure polymorphs. Pressure wave propagation in LiF, radial material flow, formation of cracks and voids are analyzed via continuum and atomistic simulations revealing a sequence of processes leading to the final structure with the long cavity. Similar results can be produced with semiconductors and ceramics, which opens a new pathway for development of laser material processing with hard x-ray pulses.

This review paper describes the energy-upgraded CEBAF accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing eighty-eight superconducting cavities that have operated CW at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance, and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for beam delivered to each of the experimental halls is summarized in the appendix., Comment: 66 pages, 73 figures, 21 tables

The production mechanism of light nuclei in heavy-ion collisions is vital to understanding the intricate details of nucleon-nucleon interactions. The coalescence of nucleons is a well-known mechanism that attempts to explain the production mechanism of these light clusters. This work investigates the formation mechanism of these nucleon clusters with a combination of coalescence and femtoscopy of nucleons and nuclei. It is achieved by appending a coalescence and correlation afterburner (\texttt{CRAB}) to the \texttt{SMASH} transport model. To have a proper view of the anisotropy of light nuclei clusters, a mean-field approach to \texttt{SMASH} is applied. The anisotropic coefficients of various light nuclei clusters are calculated and compared to experimental measurements. To incorporate hydrodynamics into the picture, the anisotropic measurements are completed in a hybrid \texttt{SMASH}+\texttt{vHLLE} mode. In both approaches, the femtoscopy of nucleons and light nuclei is performed, reported with CRAB, and compared to the latest experimental measurements. An insight into cluster formation time is drawn by extracting the emission source size with the Lednick\'y-Lyuboshits (LL) model., Comment: 10 pages, 6 figures

A novel, computationally designed, class of triangular-shape organic molecules with an inverted singlet-triplet (IST) energy gap is investigated with the aid of ab initio methods of electronic structure theory. The considered molecular systems have a form of cyclic oligomers and their common feature is electronic conjugation localized along the molecular rim. Analysis of vertical transition energies from the electronic ground state, as well as from the lowest excited singlet and triplet states of selected molecules, is conducted. The results underscore the significance of optimizing excited-state geometries in theoretical models to accurately describe the optoelectronic properties of the IST molecules, particularly in relation to their applications in OLEDs., Comment: 22 pages, 12 figures, 2 tables

Parkinson's disease is a progressive and slowly developing neurodegenerative disease, characterized by dopaminergic neuron loss in the substantia nigra region of the brain. Despite extensive research by scientists, there is not yet a cure to this problem and the available therapies mainly help to reduce some of the Parkinson's symptoms. Drug repurposing (that is, the process of finding new uses for existing drugs) receives more appraisals as an efficient way that allows for reducing the time, resources, and risks associated with the development of new drugs. In this research, we design a novel computational platform that integrates gene expression data, biological networks, and the PDOD database to identify possible drug-repositioning agents for PD therapy. By using machine learning approaches like the RWR algorithm and PDOD scoring system we arrange drug-disease conversions and sort our potential sandboxes according to their possible efficacy. We propose gene expression analysis, network prioritization, and drug target data analysis to arrive at a comprehensive evaluation of drug repurposing chances. Our study results highlight such therapies as promising drug candidates to conduct further research on PD treatment. We also provide the rationale for promising drug repurposing ideas by using various sources of data and computational approaches., Comment: 5 pages, Final Year Engineering Project on Machine Learning and Healthcare Industry

At energies that are large with respect to the electroweak scale, the electroweak corrections to scattering processes involve large logarithms that have to be resummed to obtain decent predictions. Soft-collinear effective theory (SCET) has been proposed as a suitable framework to allow for this resummation, while retaining non-logarithmic corrections in a consistent way. In this paper, we investigate the approximations needed to use this approach for the calculation of electroweak corrections to off-shell diboson production at high-energy colliders. Upon implementing the method into a Monte-Carlo integration code, we provide resummed predictions for cross sections and distributions at a 3 TeV lepton collider and a 100 TeV proton collider., Comment: 75 pages, 69 pdf figure files, some extra comments added, version that appeared in Eur. Phys. J. C

In this work, we present an open-source implementation of the enumerative sphere shaping (ESS) algorithm used for probabilistic constellation shaping (PCS). PCS aims at closing the shaping gap caused by using uniformly distributed modulation symbols in channels for which information theory shows non-uniformly distributed signaling to be optimal. ESS is one such PCS algorithm that sets itself apart as it operates on a trellis representation of a subset of the possible symbol sequences. ESS leads to an empirical distribution of the symbols that closely approximates the optimal distribution for the additive white Gaussian noise (AWGN) channel. We provide an open-source implementation of this algorithm in the compiled language Rust, as well as Python bindings with which our Rust code can be called in a regular Python script. We also compare simulation results on the AWGN channel using our implementation with previous works on this topic., Comment: Accepted for presentation at the 13th GNU Radio conference (GRCon)

The magnetization of amorphous DyCo3 and TbCo3 is studied by magnetometry, anomalous Hall effect and magneto-optic Kerr effect to understand the temperature-dependent magnetic structure. A square magnetic hysteresis loop with perpendicular magnetic anisotropy and coercivity that reaches 3.5 T in the vicinity of the compensation temperature is seen in thin films. An anhysteretic soft component, seen in the magnetization of some films but not in their Hall or Kerr loops is an artefact due to sputter-deposition on the sides of the substrate. The temperature-dependence of the net rare earth moment from 4-300K is deduced, using the cobalt moment in amorphous YxCo1-x. The single-ion anisotropy of the quadrupole moments of the 4f atoms in the randomly-oriented local electrostatic field gradient overcomes their exchange coupling to the cobalt subnetwork, resulting in a sperimagnetic ground state where spins of the noncollinear rare-earth subnetwork are modelled by a distribution of rare earth moments within a cone whose axis is antiparallel to the ferromagnetic axis z of the cobalt subnetwork. The reduced magnetization (Jz)/J at T=0 is calculated from an atomic Hamiltonian as a function of the ratio of anisotropy to exchange energy per rare-earth atom for a range of angles between the local anisotropy axis and -z and then averaged over all directions in a hemisphere. The experimental and calculated values of (J-z)/J are close to 0.7 at low temperature for both Dy and Tb. On increasing temperature, the magnitude of the rare earth moment and the local random anisotropy that creates the cone are reduced; the cone closes and the structure approaches collinear ferrimagnetism well above ambient temperature. An asymmetric spin flop of the exchange-coupled subnetworks appears in the vicinity of the magnetization compensation temperatures of 175K for amorphous Dy0.25Co0.75 and 200 K for amorphous TbCo3., Comment: 23 pages, 12 figures

In testing industry, precise item categorization is pivotal to align exam questions with the designated content domains outlined in the assessment blueprint. Traditional methods either entail manual classification, which is laborious and error-prone, or utilize machine learning requiring extensive training data, often leading to model underfit or overfit issues. This study unveils a novel approach employing the zero-shot and few-shot Generative Pretrained Transformer (GPT) classifier for hierarchical item categorization, minimizing the necessity for training data, and instead, leveraging human-like language descriptions to define categories. Through a structured python dictionary, the hierarchical nature of examination blueprints is navigated seamlessly, allowing for a tiered classification of items across multiple levels. An initial simulation with artificial data demonstrates the efficacy of this method, achieving an average accuracy of 92.91% measured by the F1 score. This method was further applied to real exam items from the 2022 In-Training Examination (ITE) conducted by the American Board of Family Medicine (ABFM), reclassifying 200 items according to a newly formulated blueprint swiftly in 15 minutes, a task that traditionally could span several days among editors and physicians. This innovative approach not only drastically cuts down classification time but also ensures a consistent, principle-driven categorization, minimizing human biases and discrepancies. The ability to refine classifications by adjusting definitions adds to its robustness and sustainability.

The stability of a dark matter detector on the timescale of a few years is a key requirement due to the large exposure needed to achieve a competitive sensitivity. It is especially crucial to enable the detector to potentially detect any annual event rate modulation, an expected dark matter signature. In this work, we present the performance history of the DarkSide-50 dual-phase argon time projection chamber over its almost three-year low-radioactivity argon run. In particular, we focus on the electroluminescence signal that enables sensitivity to sub-keV energy depositions. The stability of the electroluminescence yield is found to be better than 0.5%. Finally, we show the temporal evolution of the observed event rate around the sub-keV region being consistent to the background prediction., Comment: 13 pages, 5 figures

Magnetic properties of multicomponent alloys depend sensitively on the degree of atomic order on the different crystallographic sites. In this work we demonstrate the magnetic contrast between bulk and thin-film samples of the Heusler alloy V$_{2}$FeAl. Arc-melted bulk ingots show practically no site preference of the elements (A2 structure), whereas magnetron-sputtered thin-film samples display a higher degree of atomic ordering with a tendency towards XA-type order. Electronic structure calculations favour ferrimagnetic XA-type ordering, and the effect of different pairwise atomic disorder on the element specific and net magnetic moments are evaluated to reproduce experimental observations. XA-type thin-films with iron moment of 1.24 $\mu_{\mathrm{B}}$ determined by X-ray magnetic circular dichroism are in agreement with calculation, but the measured net moment of 1.0 $\mu_{\mathrm{B}}$ per formula unit and average vanadium moment are smaller than expected from calculations. The measured Curie temperature is approximately 500 K. Films with a higher degree of disorder have a T$_{\mathrm{C}}$ close to 300 K with a net moment of 0.1 $\mu_{\mathrm{B}}$ at low temperature. The large calculated vanadium moments are destroyed by partial disorder on $4d$ vanadium sites. By contrast, the arc-melted and annealed bulk alloy with a fully-disordered A2 structure shows no spontaneous magnetization; it is a Pauli paramagnet with dimensionless susceptibility $\chi_{\mathrm{v}}=-2.95\times10^{-4}$., Comment: 10 pages, 7 figures

The direct search for dark matter in the form of weakly interacting massive particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a target material from the WIMP elastic scattering. A promising experimental strategy for direct dark matter search employs argon dual-phase time projection chambers (TPC). One of the advantages of the TPC is the capability to detect both the scintillation and charge signals produced by NRs. Furthermore, the existence of a drift electric field in the TPC breaks the rotational symmetry: the angle between the drift field and the momentum of the recoiling nucleus can potentially affect the charge recombination probability in liquid argon and then the relative balance between the two signal channels. This fact could make the detector sensitive to the directionality of the WIMP-induced signal, enabling unmistakable annual and daily modulation signatures for future searches aiming for discovery. The Recoil Directionality (ReD) experiment was designed to probe for such directional sensitivity. The TPC of ReD was irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data were taken with 72 keV NRs of known recoil directions. The direction-dependent liquid argon charge recombination model by Cataudella et al. was adopted and a likelihood statistical analysis was performed, which gave no indications of significant dependence of the detector response to the recoil direction. The aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/- 0.027 and the upper limit is R < 1.072 with 90% confidence level, Comment: 20 pages, 10 figures, submitted to Eur. Phys. J. C

Dark matter induced event rate in an Earth-based detector is predicted to show an annual modulation as a result of the Earth's orbital motion around the Sun. We searched for this modulation signature using the ionization signal of the DarkSide-50 liquid argon time projection chamber. No significant signature compatible with dark matter is observed in the electron recoil equivalent energy range above $40~{\rm eV_{ee}}$, the lowest threshold ever achieved in such a search., Comment: 8 pages, 4 figures

Exploring anisotropy and diverse magnetization dynamics in specimens with vanishing magnetic moments presents a significant challenge using traditional magnetometry, as the low resolution of existing techniques hinders the ability to obtain accurate results. In this study, we delve deeper into the examination of magnetic anisotropy and quasi-static magnetization dynamics in \mrg\,(MRG) thin films, as an example of a compensated ferrimagnetic half-metal, by employing anomalous Hall effect measurements within a tetragonal crystal lattice system. Our research proposes an innovative approach to accurately determine the complete set of anisotropy constants of these MRG thin films. To achieve this, we perform anomalous Hall voltage curve fitting, using torque models under the macrospin approximation, which allow us to obtain out-of-plane anisotropy constants $K_1=4.0\times10^4$ J m$^{-3}$ ($K_1/M=0.655$\,T) and $K_2=2.54\times10^4$ J m$^{-3}$ ($K_2/M=0.416$\,T), along with a weaker in-plane anisotropy constant $K_3=3.48\times10^3$ J m$^{-3}$ ($K_3/M=0.057$\,T). By additionally employing first-order reversal curves (FORC) and classical Preisach hysteresis (hysterons) models, we are able to validate the efficacy of the macrospin model in capturing the magnetic behavior of MRG thin films. Furthermore, our investigation substantiates that the complex quasi-static magnetization dynamics of MRG thin films can be effectively modelled using a combination of hysteronic and torque models. This approach facilitates the exploration of both linear and non-linear quasi-static magnetization dynamics, in the presence of external magnetic field and/or current-induced effective fields, generated by the spin-orbit torque and spin transfer torque mechanisms., Comment: 14 pages, 10 figures

The blind phase search (BPS) algorithm for carrier phase estimation is known to have sub-optimal performance for probabilistically shaped constellations. We present a belief propagation based approximate maximum a posteriori carrier phase estimator and compare its performance with the standard and an improved BPS algorithm., Comment: Accepted for presentation at European Conference on Optical Communications 2023. Updated to include copyright notice

The Viterbi & Viterbi (V&V) algorithm is well understood for QPSK and 16-QAM, but modifications are required for higher-order modulation formats. We present an approach to extend the standard V&V algorithm for higher-order modulation formats by modifying the transmit constellation with geometric constellation shaping., Comment: Accepted for presentation at European Conference on Optical Communications 2023

We investigate the effect of flow fluctuations, incorporated in non boost-invariant blast-wave model, on kinetic freeze-out parameters of identified hadrons in low energy relativistic heavy-ion collisions. For the purpose of this study, we use the transverse momentum spectra of the identified hadrons produced in central Pb--Pb collisions, at SPS energies ranging from $\rm E_{Lab}=20A-158A $ GeV, and analyze them within a modified non boost-invariant blast wave model. We perform simultaneous fits of the transverse momentum spectra for light hadrons ($\pi^{-}$, $K^{\pm}$, $p$) and heavy strange hadrons ($\Lambda$, $\bar{\Lambda}$, $\phi$, $\Xi^{\pm}$, $\Omega^{\pm}$) seperately. We also fit the transverse momentum spectra of charmonia ($J/\Psi$, $\Psi'$) at $\rm E_{Lab}=158A $ GeV. Our findings suggest that the inclusion of flow fluctuations enhances kinetic freeze-out temperature in case of light and heavy strange hadrons and reduces the corresponding transverse flow velocities. Moreover, we find that the kinetic freeze-out parameters of the charmonia at $\rm E_{Lab}=158A $ GeV are least affected by inclusion of flow fluctuations. Based on this, we make predictions which can provide further insights on the role of flow fluctuations in relativistic heavy-ion collisions., Comment: 11 pages, 8 figures, Accepted in Phys. Rev. C, Version to appear in the journal

We present a novel approach for the search of dark matter in the DarkSide-50 experiment, relying on Bayesian Networks. This method incorporates the detector response model into the likelihood function, explicitly maintaining the connection with the quantity of interest. No assumptions about the linearity of the problem or the shape of the probability distribution functions are required, and there is no need to morph signal and background spectra as a function of nuisance parameters. By expressing the problem in terms of Bayesian Networks, we have developed an inference algorithm based on a Markov Chain Monte Carlo to calculate the posterior probability. A clever description of the detector response model in terms of parametric matrices allows us to study the impact of systematic variations of any parameter on the final results. Our approach not only provides the desired information on the parameter of interest, but also potential constraints on the response model. Our results are consistent with recent published analyses and further refine the parameters of the detector response model., Comment: 24 pages, 12 figures, 1 table

The cubic Heusler alloy Ru$_{2-x}$Mn$_{1+x}$Al is grown in thin film form on MgO and MgAl$_2$O$_4$ substrates. It is a highly spin-polarised ferrimagnetic metal, with weak magnetocrystalline anisotropy. Although structurally and chemically similar to $\text{Mn}_2\text{Ru}_x\text{Ga}$, it does not exhibit ferrimagnetic compensation, or large magneto galvanic effects. The differences are attributed to a combination of atomic order and the hybridisation with the group 13 element Al or Ga. The spin polarisation is around 50 to 60 %. There is a gap in the density of states just above the Fermi level in fully ordered compounds., Comment: 8 pages , 7 figures, 2 tables

As the demand for higher data throughput in coherent optical communication systems increases, we need to find ways to increase capacity in existing and future optical communication links. To address the demand for higher spectral efficiencies, we apply end-to-end optimization for joint geometric and probabilistic constellation shaping in the presence of Wiener phase noise and carrier phase estimation. Our approach follows state-of-the-art bitwise auto-encoders, which require a differentiable implementation of all operations between transmitter and receiver, including the DSP algorithms. In this work, we show how to modify the ubiquitous blind phase search (BPS) algorithm, a popular carrier phase estimation algorithm, to make it differentiable and include it in the end-to-end constellation shaping. By leveraging joint geometric and probabilistic constellation shaping, we are able to obtain a robust and pilot-free modulation scheme improving the performance of 64-ary communication systems by at least 0.1bit/symbol compared to square QAM constellations with neural demappers and by 0.05 bit/symbol compared to previously presented approaches applying only geometric constellation shaping., Comment: revised version and to be published in JLT

We show that separating the in-phase and quadrature component in optimized, machine-learning based demappers of optical communications systems with geometric constellation shaping reduces the required computational complexity whilst retaining their good performance., Comment: Submitted to the Optical Fiber Communication Conference (OFC) 2023

We propose a novel method to optimize the structure of factor graphs for graph-based inference. As an example inference task, we consider symbol detection on linear inter-symbol interference channels. The factor graph framework has the potential to yield low-complexity symbol detectors. However, the sum-product algorithm on cyclic factor graphs is suboptimal and its performance is highly sensitive to the underlying graph. Therefore, we optimize the structure of the underlying factor graphs in an end-to-end manner using machine learning. For that purpose, we transform the structural optimization into a clustering problem of low-degree factor nodes that incorporates the known channel model into the optimization. Furthermore, we study the combination of this approach with neural belief propagation, yielding near-maximum a posteriori symbol detection performance for specific channels., Comment: Accepted at ICASSP 2023