The European Physical Journal Plus最新文献

{"title":"Dipole–dipole interaction enhanced higher-order diffraction in hybrid system","authors":"Bassam Z. Shakhreet,&nbsp;Maged Faihan Alotaibi,&nbsp;Munisa Abzalova,&nbsp;Ozodbek Nematov,&nbsp;Mohammed Saad Al-Ghamdi,&nbsp;Amr Ali Mohamed Abdelgawwad El-Sehrawy,&nbsp;Lamia Adam Albedair","doi":"10.1140/epjp/s13360-026-08361-6","DOIUrl":"10.1140/epjp/s13360-026-08361-6","url":null,"abstract":"<div><p>In this study, we examined the dipole–dipole interaction (DDI) on the Fraunhofer diffraction pattern of a weak probe light incident in a hybrid quantum system comprising a nonlinear photonic crystal with three-level donor and acceptor quantum dots (QDs). We used two distinct scenarios to investigate the optical diffraction patterns of the probe light. In the first scenario, we examine a symmetric one-dimensional standing wave (1DSW) coupling light. Probe diffraction is anticipated to be evenly diffracted at both positive and negative angles. Nonetheless, in the second scenario, we apply a suitable position-dependent modification to two-photon detuning, which can alter the parity of the dispersion, resulting in unusual unidirectional diffraction of the probe light. We observed that the interaction between the DDI and the QD-field greatly enhanced the dispersion characteristics of the hybrid system. Consequently, the probe energy can be transferred to higher-order diffraction.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098219","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}

{"title":"Gauss–Bonnet corrections to complexity growth with a probe string","authors":"Wen-Bin Chang","doi":"10.1140/epjp/s13360-026-08374-1","DOIUrl":"10.1140/epjp/s13360-026-08374-1","url":null,"abstract":"<div><p>We investigate the effect of Gauss–Bonnet (GB) corrections on holographic complexity growth within the framework of the Complexity=Action (CA) conjecture. By introducing a probe string into a GB <i>AdS</i> black brane background, we analyze the time derivative of the Nambu-Goto (NG) action as the holographic dual to complexity growth. Our results indicate that the complexity growth is maximized for a stationary string and is suppressed by its motion. At fixed temperature, the stationary string complexity growth is independent of the GB coupling, whereas that of moving strings is suppressed by stronger GB corrections. Finally, the growth rate is shown to increase linearly with temperature, confirming that higher temperatures systematically drive the complexity growth.\u0000</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098181","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}

{"title":"Classical and semiclassical probes of dimension-dependent effective geometries","authors":"A. F. Cantun","doi":"10.1140/epjp/s13360-026-08381-2","DOIUrl":"10.1140/epjp/s13360-026-08381-2","url":null,"abstract":"<div><p>We introduce and analyze two static, spherically symmetric effective geometries with explicit dependence on the number of spatial dimensions, motivated by defect-like configurations supported by anisotropic stress–energy. The resulting backgrounds exhibit distinct global properties: One is non-asymptotically flat, while the other contains a curvature singularity whose influence on semiclassical observables can be systematically controlled through a near-core expansion. Classical properties are investigated using effective gravitational potentials, null geodesics, and gravitational lensing. We find either saturated or short-ranged deflection profiles that differ qualitatively from the Schwarzschild and Tangherlini cases and depend sensitively on the spatial dimension. The associated effective energy density, isotropic pressure, and anisotropic stress display a pronounced dimension-dependent structure, indicating a crossover in the stress–energy behavior driven by dimensionality. As a semiclassical probe, we study massless scalar two-point functions in a conformal vacuum and obtain a dimension-dependent spectral behavior near the defect core. These results identify a regime in which global geometric features and stress anisotropy, rather than local curvature alone, dominate both classical and semiclassical observables.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098182","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}

{"title":"Renormalization, decoupling and the hierarchy problem","authors":"Kang-Sin Choi","doi":"10.1140/epjp/s13360-026-08362-5","DOIUrl":"10.1140/epjp/s13360-026-08362-5","url":null,"abstract":"<div><p>The hierarchy problem is associated with renormalization and decoupling. The smallness of the scalar mass against loop corrections follows from the decoupling of heavy fields, once the observable is correctly identified as the renormalized mass depending on the external momentum rather than a constant parameter. We reconsider the properties of the renormalized loop corrections, which are finite, independent of regularization and admit a well-defined perturbative expansion, so that a quadratic dependence on a regulator cutoff carries no physical information. The substantive question is the dependence on a physical heavy mass <i>M</i>, and we show, by explicit calculation up to two loops and by power counting to all orders, that the renormalized correction to the scalar mass-squared from a heavy field is suppressed as <span>((p^2-m_h^2)^2/M^2)</span>, where <i>p</i> is the external momentum and <span>(m_h)</span> is the scalar pole mass, provided that the couplings are held fixed as <span>(M rightarrow infty)</span>. The surviving momentum dependence is in principle measurable. This is in accordance with the Appelquist–Carazzone decoupling theorem, whose statement holds up to the renormalization of the light masses and which we make explicit for the scalar mass. We do not address the origin of the small tree-level mass.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098453","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}

{"title":"Precise efficiency calibration of a p-type HPGe detector: dead layer optimization and near-field TCS analysis via PHITS simulation","authors":"Abdelwahab Badague,&nbsp;Hamid Bounouira,&nbsp;Iliasse Aarab,&nbsp;Jamila Yousfi,&nbsp;Abdessamad Didi,&nbsp;Hamid Amsil,&nbsp;Taibi Zidouz,&nbsp;El Mahjoub Chakir","doi":"10.1140/epjp/s13360-026-08383-0","DOIUrl":"10.1140/epjp/s13360-026-08383-0","url":null,"abstract":"<div><p>Accurate efficiency calibration of high-purity germanium (HPGe) detectors is a critical requirement for quantitative gamma-ray spectrometry, particularly in fields like neutron activation analysis. This study describes the development and rigorous validation of a Monte Carlo simulation model using the particle and heavy ion transport code system (PHITS) for a p-type coaxial HPGe detector (Baltic Scientific Instruments GCD-30200). To achieve high-fidelity modeling, the detector’s dead layer thickness was systematically optimized by comparing simulated full-energy peak efficiencies (FEPE) with experimental measurements from standard ¹³⁷Cs and ¹⁵²Eu point sources. The optimization process identified 1.2 mm as the optimal dead layer thickness, yielding a mean relative deviation of less than 0.5% in the highly sensitive low-energy region. To further assess the geometric integrity of the model and distinguish structural errors from physical summation effects, the efficiency was evaluated across six distinct source-to-detector distances ranging from 3.8 to 18.06 cm. The results demonstrated strong stability in far-field geometries, with relative deviations predominantly falling within a standard ± 5% acceptance region for counting distances of 10.4 cm and greater. Conversely, uncorrected near-field measurements at 3.8 cm revealed a systematic negative bias due to true coincidence summing (TCS) effects, causing experimental efficiencies to fall substantially below the simulated predictions. By applying coincidence summing factors (CSF) calculated via the Efftran code to account for “summing out” losses, the residual relative deviation at 3.8 cm was reduced to a stable, uniform band between 6.51% and 8.46% across the entire energy spectrum. Overall, the results demonstrate that a single, precisely optimized PHITS model can accurately predict detector efficiency across varied configurations, provided that analytical TCS corrections are applied for close-geometry measurements involving multi-nuclide cascades.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098454","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}

{"title":"Coherent feedback-enhanced asymmetry of thermal process in open quantum systems: cavity optomechanics","authors":"Hamza Harraf,&nbsp;Mohamed Amazioug,&nbsp;Reem Altuijri,&nbsp;Rachid Ahl Laamara,&nbsp;R. T. Matoog,&nbsp;Abdel-Haleem Abdel-Aty","doi":"10.1140/epjp/s13360-026-08348-3","DOIUrl":"10.1140/epjp/s13360-026-08348-3","url":null,"abstract":"<p> Entropy production is a fundamental quantity in nonequilibrium thermodynamics, serving as a direct measure of the irreversibility associated with physical processes. In this work, we investigate the steady-state enhancement of irreversibility by employing a coherent feedback loop. We evaluate the steady-state entropy production rate and quantum correlations by applying the quantum phase-space formulation to calculate the entropy change. Our study reveals the essential contribution of coherent feedback to the thermal bath’s input noise operators, resulting in the system being driven far from thermal equilibrium. Our analysis shows that, in the small-coupling limit, the entropy production rate is proportional to the quantum mutual information. As an application, we use a Fabry–Pérot cavity optomechanical system and show that the peaks of the entropy production corresponding to the heating/cooling of the movable mirror are enhanced. Therefore, we conclude that irreversibility and quantum correlations are not independent and must be analyzed jointly. The results demonstrate the possibility of enhancing entropy production and pave the way for promising quantum thermal applications through a coherent feedback loop.\u0000</p>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098484","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}

{"title":"Overturning the measurement postulate: continuous thermodynamic localization vs. wavefunction collapse and statistical ensembles","authors":"Dragoş-Victor Anghel","doi":"10.1140/epjp/s13360-026-08343-8","DOIUrl":"10.1140/epjp/s13360-026-08343-8","url":null,"abstract":"<div><p>The quantum measurement postulate remains a fundamental physical contradiction, enforcing a non-unitary, observer-dependent projection that interrupts the continuous dynamical evolution governed by the Schrödinger equation. In this work, we demonstrate that the orthodox instantaneous collapse postulate is both a thermodynamic impossibility and a logical redundancy. The observer-dependent actualization of macroscopic particle ensembles would require an instantaneous deposition of latent heat (<span>(dt rightarrow 0)</span>), triggering an unphysical, infinite power divergence that delivers a macroscopic thermal shock, fundamentally contradicting the thermodynamic stability of the apparatus. Moreover, because an unobserved apparatus must undergo continuous open-system thermodynamic relaxation prior to conscious inspection, any subsequent mathematical projection is theoretically obsolete. Furthermore, we mathematically invalidate leading alternative theories, proving that mean-field thermodynamic ensemble models (such as the Allahverdyan, Balian, and Nieuwenhuizen formalism) fundamentally contradict their own claims: while explicitly attempting to derive the probabilistic actualization dictated by the Born rule, they inadvertently force deterministic single-run outcomes. We emphasize that our critique and the theoretical framework proposed herein are explicitly directed at the objective actualization of individual quantum systems. Consequently, the purely statistical ensemble interpretation—which conceptually bypasses the single-run measurement problem—falls outside the scope of the present analysis. To replace these untenable paradigms, we establish the Open-System Measurement Framework (OSMF), shifting the focus entirely to the continuous, objective physical evolution of the individual wavefunction. We demonstrate that the quantum system-apparatus interaction generates a transient, thermodynamically unstable macroscopic superposition. Driven by its coupling to a reservoir, this state rapidly undergoes a continuous thermodynamic relaxation into a stable local minimum of its thermodynamic potential, actualizing a definite outcome. By applying the OSMF to canonical experiments, we prove that measurement is an objective, irreversible process. Crucially, this framework seamlessly reconciles Bell-type non-local correlations (the EPR paradox) with the strict causal constraints of special relativity by providing a local, continuous physical mechanism for outcome actualization.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-026-08343-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transverse relaxation time of xenon atoms in Rb/Xe hot atomic vapor cell via single beam modulated method","authors":"M. Sotoudeh,&nbsp;S. M. Hamidi","doi":"10.1140/epjp/s13360-026-08385-y","DOIUrl":"10.1140/epjp/s13360-026-08385-y","url":null,"abstract":"<div><p>This study investigates the transverse relaxation time (<i>T₂</i>) of xenon atoms in a hot rubidium/xenon (Rb/Xe) vapor cell. Alkali-metal vapor cells serve as the core of many quantum sensors, including nuclear magnetic resonance gyroscopes (NMRGs), which are widely used in navigation applications. The transverse relaxation time (<i>T₂</i>) of xenon nuclear spins in an atomic vapor cell as one of the key parameters in nuclear magnetic resonance (NMR) and hyperpolarized gas experiments affects coherence times and measurement sensitivity and also directly influences the angular random walk of the gyroscope. Here using optical pumping techniques and magneto-optical detection, the <i>T₂</i> of xenon atoms was measured under different temperatures. The results indicate that the transverse relaxation time is strongly affected by collisional interactions between xenon and rubidium atoms as well as wall-induced relaxation in the vapor cell. These findings provide valuable insights for optimizing experimental conditions in quantum sensing applications and contribute to a better understanding of spin dynamics in hot atomic vapors. Experimental results demonstrate that the constructed Rb/Xe vapor cell can achieve a transverse relaxation time (<i>T₂</i>) of 10.58 s under static conditions at 75 °C. Over a cell temperature range of 70 to 110 °C, <i>T₂</i> decreases with increasing temperature, while the signal amplitude increases inversely.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098245","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}

{"title":"The magnetic properties of a doped asymmetric GaAs double quantum dot in electromagnetic fields","authors":"Khaled Abdulhaq,&nbsp;Mohammad Elsaid,&nbsp;Diana Dahliah","doi":"10.1140/epjp/s13360-026-08332-x","DOIUrl":"10.1140/epjp/s13360-026-08332-x","url":null,"abstract":"<div><p>The eigenenergies of an electron that confined within an asymmetric double quantum dots (DQD) have been solved via the exact diagonalization method. The model includes the effects of the existence of donor/acceptor impurity and the presence of external electric and magnetic fields. The influence of localization, strength and the position of the Gaussian impurity on the magnetic properties has been investigated as a function of the magnetic and electric fields. The results show a transition from paramagnetic to diamagnetic behavior at low temperatures due to the impurity presence. The previous parameters of the Gaussian impurity have modified the magnetic transition temperature. As the strength of the impurity increases, the paramagnetic diamagnetic transition occurs at a lower temperature.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098153","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}

{"title":"Vector similaritons in two-mode optical media with cubic-quintic nonlinearity and four-wave mixing","authors":"Mohammed Kamel Rabia,&nbsp;Houria Triki,&nbsp;Nan Wang","doi":"10.1140/epjp/s13360-026-08376-z","DOIUrl":"10.1140/epjp/s13360-026-08376-z","url":null,"abstract":"<div><p>We present the discovery of chirped vector similaritons which can propagate through inhomogeneous two-mode media exhibiting four-wave mixing and quintic nonlinearity. The transmission of nonlinear wave packets in such optical waveguiding medium is studied in the framework of a generalized system of coupled nonlinear Schrödinger equations in (3+1)-dimensions which accounts for spatially inhomogeneous diffraction/dispersion, third-order self- and cross-nonlinear effects, fifth-order self-nonlinear effects, four-wave mixing, and linear gain/loss. It is shown that two distinct families of coupled self-similar periodic waves taking the <span>(textrm{dn})</span>-<span>(textrm{dn})</span> and <span>(textrm{cn})</span>-<span>(textrm{cn})</span> configurations on continuous wave backgrounds exist in the medium. A family of spatiotemporal bright-dark vector similaritons is identified in the long-wave limit of the generated coupled periodic waves. As a practical application, we investigate the propagation dynamics of the obtained chirped vector similaritons in an exponential dispersion-decreasing fiber as well as a periodic distributed fiber system. The results indicate that a proper selection of diffraction/dispersion and gain/loss profiles allows diverse propagation trajectories for the three-dimensional bright-dark vector similaritons. It is also demonstrated that the chirp parameter enables us to manipulate the amplitude and the width of vector similariton pulses as they propagate through the inhomogeneous media in accordance with the system parameters.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149098008","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}