The European Physical Journal Plus最新文献_第7页

Engineering stress-energy signs in a subluminal Alcubierre analog using Casimir cavities and magnetized plasma 利用卡西米尔空腔和磁化等离子体在亚腔阿尔库别雷模拟中的工程应力-能量信号

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-28 DOI: 10.1140/epjp/s13360-026-07538-3

Hicham Zejli

{"title":"Engineering stress-energy signs in a subluminal Alcubierre analog using Casimir cavities and magnetized plasma","authors":"Hicham Zejli","doi":"10.1140/epjp/s13360-026-07538-3","DOIUrl":"10.1140/epjp/s13360-026-07538-3","url":null,"abstract":"<div>The Alcubierre metric enables apparent hyperfast travel via local spacetime distortion but requires exotic energy. We propose a subluminal, analog framework in which a Casimir–plasma hybrid is used to engineer stress–energy sign structure: (i) arrays of micro/nanostructured Casimir cavities provide a localized, boundary-induced negative stress/energy signature; (ii) a co-located magnetized plasma ((v_{text{p}}!sim !0.1c)) supplies an independently diagnosed positive laboratory EM/plasma background quantified by standard diagnostics. We prescribe a modified Alcubierre line element with a normalized double–(tanh) profile (f_C(r)) (unity inside, vanishing outside), ensuring regularity and no horizons, and use it kinematically to encode the sign pattern ((T^{00}_{text {geom}}=0) interior/exterior and (T^{00}_{text {geom}}<0) in the wall). We do not claim a self-consistent Einstein–Maxwell solution for the combined sources with the same metric. The goal is controllable sign contrast and metrology consistent with quantum-inequality bounds. We outline two testbeds: (i) a tabletop Casimir–plasma setup (30–100 nm gaps, 1–10 T pulsed fields) and (ii) a facility-scale Z-pinch ((sim)20 MA, (sim)100 ns), both targeting photon transit time/phase diagnostics across the engineered wall. Our objective is not to generate measurable curvature but to validate methods for stress–energy sign engineering in a subluminal, horizon-free setting.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The possibility of fairly mitigating penalties in the quantum Prisoner’s Dilemma via classical noise channels 通过经典噪声信道在量子囚徒困境中减轻惩罚的可能性

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-27 DOI: 10.1140/epjp/s13360-026-07650-4

A. T. M. Makram-Allah, M. Y. Abd-Rabbou, N. Metwally

{"title":"The possibility of fairly mitigating penalties in the quantum Prisoner’s Dilemma via classical noise channels","authors":"A. T. M. Makram-Allah, M. Y. Abd-Rabbou, N. Metwally","doi":"10.1140/epjp/s13360-026-07650-4","DOIUrl":"10.1140/epjp/s13360-026-07650-4","url":null,"abstract":"<div>The effectiveness of different types of classical noise in maximizing or minimizing the expected payoffs for two players attempting to solve the Prisoner’s Dilemma is discussed. It is shown that the behavior of the payoffs depends on the initial states of the players, specifically their symmetric or polarized nature, the classical/quantum defection strategies, and the degree of Markovianity. The results show that when both players start in identical states and use the quantum defection strategy, they receive equal payoffs that do not exceed the classical bounds of cooperation. However, when the initial states differ, the dynamics change: if one player attains the maximum payoff, the other incurs the minimum payoff, and their payoffs oscillate within their respective upper and lower bounds, with each player’s gain occurring at the expense of the other. The oscillatory behavior is dominant, originating from the continuous time-dependent unitary evolution and, in non-Markovian regimes, the backflow of information from the environment. Extremely fast oscillations are predicted when the channel strength is exponentially time-dependent due to the rapid exponential accumulation of the entangling phase. Maximizing/minimizing the expected payoffs depends on the Markovianity of the used channel. In the presence of the Modified Ornstein–Uhlenbeck (MOU) noisy channel, the upper bounds of all expected payoffs become nearly identical, regardless of whether the players adopt cooperative strategies or employ the quantum defection strategy. In the presence of Random Telegraph Noise (RTN) and MOU noisy channels, the lower bound of the payoffs increases as the game duration increases, while they are similar if the game is implemented in the presence of the Power-Law Noise (PLN) channel.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Laser irradiation-induced enhancement of photoluminescence and optical properties of PEG/BaO nanocomposite films: experimental and DFT investigations 激光辐照增强PEG/BaO纳米复合薄膜的光致发光和光学性能：实验和DFT研究

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-27 DOI: 10.1140/epjp/s13360-026-07666-w

Ahmed R. Ghazy, Nasser Almutlaq, A. Ibrahim, Mamduh J. Aljaafreh, Riyad Ghazy

{"title":"Laser irradiation-induced enhancement of photoluminescence and optical properties of PEG/BaO nanocomposite films: experimental and DFT investigations","authors":"Ahmed R. Ghazy, Nasser Almutlaq, A. Ibrahim, Mamduh J. Aljaafreh, Riyad Ghazy","doi":"10.1140/epjp/s13360-026-07666-w","DOIUrl":"10.1140/epjp/s13360-026-07666-w","url":null,"abstract":"<div>The structural, optical, and electrical characteristics of BaO-doped polyethylene glycol (PEG) nanocomposite films were examined in this study after they were created using a dip-coating technique. FTIR, XRD, SEM, TGA, UV–Vis spectroscopy, and density functional theory (DFT) simulations were used to analyze the formed films with BaO concentrations of 0.015, 0.020, and 0.025. A non-monotonic shift in crystallinity was discovered by XRD analysis: The average crystallite size dropped from 143.62 nm (pure PEG) to 119.19 nm (0.020 BaO) and then rose to 131.89 nm at 0.025 BaO, suggesting partial structural reordering after initial disruption. SEM demonstrated the progressive integration and distribution of BaO particles within the PEG matrix, while TGA confirmed increased heat resistance with increasing inorganic residue (from 1% for PEG to 13.5% for PEG/0.025 BaO), indicating successful nanocomposite formation. Optical properties investigations revealed a bandgap narrowing from 4.51 eV (PEG) to 4.05 eV (0.025 BaO), while the dispersion energy (Ed) increased from 7.76 to 16.16 eV and the refractive index increased from 1.379 to 1.685. Doping also resulted in a considerable improvement in the nonlinear refractive index (n2) and third-order nonlinear susceptibility (χ3). Tunable visible–NIR emissions were detected by photoluminescence, peaking at 0.020 BaO and then quenching at 0.025 because of potential agglomeration. Improved thermodynamic stability, charge redistribution, and bandgap decrease (from 4.469 to 3.890 eV) were all validated by TD-DFT simulations. Laser irradiation of PEG/0.020 BaO films revealed tunable optical constants, reduced the bandgap from 4.16 to 3.95 eV, and increased photoluminescence intensity.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Solitons and breathers for the (2+1)-dimensional Hirota’s system （2+1）维Hirota系统的孤子和呼吸子

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-26 DOI: 10.1140/epjp/s13360-026-07678-6

Jian Chang, Zhaqilao

引用次数: 0

Conv-LCTNet: a Taylor-aware deep learning approach using ConvXGB and Log-Cross Entropy loss for brain stroke detection from multimodal imaging 卷积lctnet：一种泰勒感知的深度学习方法，使用ConvXGB和对数交叉熵损失从多模态成像中检测脑卒中

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-26 DOI: 10.1140/epjp/s13360-026-07655-z

S. Monika, M. Sangeetha

{"title":"Conv-LCTNet: a Taylor-aware deep learning approach using ConvXGB and Log-Cross Entropy loss for brain stroke detection from multimodal imaging","authors":"S. Monika, M. Sangeetha","doi":"10.1140/epjp/s13360-026-07655-z","DOIUrl":"10.1140/epjp/s13360-026-07655-z","url":null,"abstract":"<div>Stroke is considered a cerebrovascular disorder that causes severe damage to brain tissues, leading to complete loss of motor abilities in patients, if left untreated. Clinically, information from brain images, like computed tomography (CT) and magnetic resonance imaging (MRI), is used to provide a better diagnosis by identifying abnormal areas in the brain. Nowadays, various techniques are used to detect stroke with high accuracy by extracting essential information from the images. Meanwhile, the existing methods often struggle to combine multimodal data and are affected by the inherent noise in the images. This paper presents a convolutional log cross-entropy Taylor network (Conv-LCTNet) for brain stroke detection. Here, the input CT and MRI images are acquired from the dataset, and then, the images are augmented using a generative adversarial network (GAN). The augmented images are separately used for image preprocessing. Further, the preprocessed images are segmented using the dual adaptive cuckoo catfish optimizer network (DCCO-Net), and multiple features are extracted using various extractors. Following this, the features are concatenated and applied to Conv-LCTNet for detecting brain stroke. Evaluations show that the Conv-LCTNet attained a high recall of 97.031%, precision of 96.025%, F measure of 96.525%, and accuracy of 96.489%.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Biodiversity and ecosystem dynamics: stochastic transitions in a Holling–Tanner model with harvesting and fear 生物多样性和生态系统动力学：具有收获和恐惧的Holling-Tanner模型中的随机转变

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-26 DOI: 10.1140/epjp/s13360-026-07708-3

Bapin Mondal

引用次数: 0

Optimizing 192Ir Leipzig applicator dosimetry for multi-tissue irradiation: a Monte Carlo analysis of skin, adipose, and bone response to material and aperture variations 优化192Ir莱比锡涂抹器剂量法用于多组织照射：皮肤，脂肪和骨骼对材料和孔径变化的反应的蒙特卡罗分析

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-26 DOI: 10.1140/epjp/s13360-026-07674-w

Roya Boudaghi Malidarreh, Sajad Keshavarz, Hesham M. H. Zakaly

{"title":"Optimizing 192Ir Leipzig applicator dosimetry for multi-tissue irradiation: a Monte Carlo analysis of skin, adipose, and bone response to material and aperture variations","authors":"Roya Boudaghi Malidarreh, Sajad Keshavarz, Hesham M. H. Zakaly","doi":"10.1140/epjp/s13360-026-07674-w","DOIUrl":"10.1140/epjp/s13360-026-07674-w","url":null,"abstract":"<div>This work aims to identify the optimal shielding material for the Leipzig applicator used in superficial skin brachytherapy. The MCNPX Monte Carlo code was employed to simulate absorbed and mean dose distributions in a tissue phantom. Simulations were performed for various applicator shielding materials (Cu, Ti, medical-grade plastic, and W), aperture radii (0.5–1.5 cm), and penetration depths. For all materials, the highest absorbed dose was delivered to the superficial skin layer (0.0–0.2 cm depth), while the lowest dose was observed at bone tissue depths (0.7–1.7 cm). W provided the most effective shielding, yielding the lowest absolute dose across all configurations. A marked dose reduction was observed with increasing penetration depth. Furthermore, as the aperture radius increased, the mean dose for the W-shielded applicator configuration increased by approximately 2%, whereas it decreased by about 1% for the Cu and Ti configurations. This investigation conclusively establishes the efficacy of the MCNPX Monte Carlo simulation code in the systematic evaluation of material compositions for Leipzig applicators. The analysis identifies W material as the optimal material for radiation shielding, based on its superior performance metrics. Furthermore, the results delineate an explicit, material-specific dependency of mean dose on variations in applicator aperture geometry.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exploring beauty bound states: mass spectra and decay dynamics of B mesons and (bqbar{q}bar{q}) tetraquarks 探索美界态：B介子和(bqbar{q}bar{q})四夸克的质谱和衰变动力学

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-26 DOI: 10.1140/epjp/s13360-026-07724-3

Chetan Lodha, Manak Parmar, Ajay Kumar Rai

{"title":"Exploring beauty bound states: mass spectra and decay dynamics of B mesons and (bqbar{q}bar{q}) tetraquarks","authors":"Chetan Lodha, Manak Parmar, Ajay Kumar Rai","doi":"10.1140/epjp/s13360-026-07724-3","DOIUrl":"10.1140/epjp/s13360-026-07724-3","url":null,"abstract":"<div>We present a detailed, model-driven study of beauty-containing hadrons that combines spectroscopy with decay phenomenology. Within a diquark–antidiquark framework, conventional (B) mesons and exotic (bqbar{q}bar{q}) tetraquarks are treated using complementary non-relativistic and semi-relativistic two-body formalisms. The interquark dynamics are described by a Cornell-type potential, augmented by Breit–Fermi spin-dependent interactions including spin-spin, spin-orbit, and tensor terms, with short-range effects regulated through finite-size smearing. Diquarks are modeled as effective quasiparticles, and tetraquark masses are obtained by solving the Schrödinger equation, with threshold effects incorporated where relevant. Nonleptonic (B)-meson decay amplitudes are evaluated in the factorization approach employing model form factors, while tetraquark decay widths are estimated using Fierz-rearranged operator structures and overlap integrals that account for fall-apart mechanisms. The resulting mass spectra and decay patterns are compared with available experimental information, enabling structural assignments of observed states and providing quantitative predictions for key observables within the compact diquark–antidiquark picture.\u0000</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigating potential anomalies, environmental implications, and a radiological risk assessment of natural radioactivity in soil from the Kurdistan Region of Iraq 调查伊拉克库尔德斯坦地区土壤中天然放射性的潜在异常、环境影响和辐射风险评估

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-25 DOI: 10.1140/epjp/s13360-026-07667-9

Mohammed I. M. Mustafa, Rabee B. Alkhayat, Dilshad Salih Ismael, Dldar Saleh Ismael, Twana A. Mustafa

{"title":"Investigating potential anomalies, environmental implications, and a radiological risk assessment of natural radioactivity in soil from the Kurdistan Region of Iraq","authors":"Mohammed I. M. Mustafa, Rabee B. Alkhayat, Dilshad Salih Ismael, Dldar Saleh Ismael, Twana A. Mustafa","doi":"10.1140/epjp/s13360-026-07667-9","DOIUrl":"10.1140/epjp/s13360-026-07667-9","url":null,"abstract":"<div>This study investigates the natural radioactivity levels in soil samples and evaluates the associated radiological risks in the Qaladiza district, Kurdistan region, Iraq. A total of sixty-one soil samples were collected from nine locations and categorized into three groups (A, B, and other sites). The samples were analyzed using a high-purity germanium (HPGe) detector to determine the activity concentrations and estimate potential radiological hazards. The mean activity concentrations were found to be 72.77 ± 3.20 Bq kg−1 for 226Ra, 26.43 ± 0.69 Bq kg−1 for 232Th, and 312.20 ± 4.96 Bq kg−1 for 4⁰K in site A. In site B, the mean levels of activity concentrations were 51.31 ± 2.81 Bq kg−1 for 226Ra, 29.31 ± 0.84 Bq kg−1 for 232Th, and 402.37 ± 5.51 Bq kg−1 for 4⁰K. At other sites, averages were 29.66 ± 2.25 Bq kg−1, 14.54 ± 0.51 Bq kg−1, and 244.45 ± 4.98 for 226Ra, 232Th, and 4⁰K, respectively. The average activity of 226Ra in both sites A and B exceeded the global average. The average values for radium equivalent, annual effective dose, and external and internal hazard indices were all within international safety limits. However, absorbed dose rates at site A exceeded the global average. The average of the excess lifetime cancer risk was below the global benchmark but several samples within A and B sites exceeded threshold values. The average value of annual equivalent gonadal dose was higher than the worldwide limit at A and B sites. This work emphasizes the possible radiation risk related to natural radioactivity concentrations in the soil of Qaladiza regions to evaluate precious facts for safety and public health.</div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147796784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deformed compact objects in modified gravity 在改变重力下变形的致密物体

IF 2.9 3区物理与天体物理

The European Physical Journal Plus Pub Date : 2026-04-25 DOI: 10.1140/epjp/s13360-026-07680-y

J. T. Quartuccio, P. H. R. S. Moraes

引用次数: 0