The European Physical Journal D最新文献

{"title":"Impact of initial electron distributions at the photocathode in RF photoinjectors on radiation parameters","authors":"Mikhail Vladimirov,&nbsp;Andrew Batov,&nbsp;Sergey Polozov","doi":"10.1140/epjd/s10053-026-01267-z","DOIUrl":"10.1140/epjd/s10053-026-01267-z","url":null,"abstract":"<p>The paper discusses the effect of the initial electron bunch distribution on the angular and spectral parameters of the radiation the bunch produces when passing periodic structures. The realistic electron bunch distributions in the vicinity of the photocathode are obtained with the use of the dedicated numerical code <span>PhDyn</span>. The beam dynamics for electron bunches in the radio-frequency photogun and the linear accelerator following it are calculated using the <span>BEAMDULAC_BL-photogun</span> code. The electron phase space distributions obtained with this code are subsequently used to simulate spiral undulator and channeling radiations. The results reveal significant deviations in the spectral-angular distributions when realistic initial distributions are used, highlighting the importance of accurate modeling of the photocathode emission process.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149338253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Synchrotron radiation of twisted photons","authors":"G. Yu. Lazarenko,&nbsp;N. I. Malygina","doi":"10.1140/epjd/s10053-026-01273-1","DOIUrl":"10.1140/epjd/s10053-026-01273-1","url":null,"abstract":"<p>The paper considers the possibility of using synchrotron radiation as a source of photons carrying OAM. We derive a simple formula describing the spectral-angular distribution of photons as a function of their OAM and polarization. This formula describes the general properties of synchrotron radiation regardless of the specific field configuration or particle energy. We show that the radiation properties are symmetric under the simultaneous reversal of the signs of the OAM and the photon spin. As a result, the total OAM per photon in synchrotron radiation is zero. We numerically show how much energy corresponds to radiation with definite values of OAM and polarization. More than <span>(86%)</span> of the total energy emitted in synchrotron radiation is in the form of twisted photons. We determine the frequencies and angles at which the maximum energy loss occurs for given values of OAM and polarization. In addition, the paper provides the corresponding values of the radiated energy at these maxima.\u0000</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 11","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149310716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Electron vortex ordering in the short pulse ionization of polarized atoms","authors":"Philipp A. Davydiak,&nbsp;Alexei V. Meremianin,&nbsp;Nikolai L. Manakov","doi":"10.1140/epjd/s10053-026-01275-z","DOIUrl":"10.1140/epjd/s10053-026-01275-z","url":null,"abstract":"<p>We investigate “quantum vortices” (QV) in the amplitude of the ionization of polarized atoms by few-cycle circularly polarized (CP) pulses. These are zeros of the ionization amplitude, which are seen as swirls in the amplitude’s velocity field. By analyzing results of numerical simulations of the ionization of polarized atoms by left- and right-hand CP (LCP and RCP) pulses, we have found that positions of QVs in the momentum space exhibit some regularities when ionization is performed in the multiphoton regime. Namely, QVs in the emission plane perpendicular to the pulse propagation direction occur in points with the same momentum <i>p</i> but different emission angles <span>(varphi )</span> for both, RCP and LCP pulses. Based on the parametrization of the ionization amplitude within the non-stationary perturbation theory (PT), we present arguments explaining the vortex position rule. Apart from that, by representing the multipole terms of the ionization amplitude as vectors on a complex plane, we demonstrate that QVs can be associated with polygonal figures, which are topologically equivalent in the cases of the ionization by RCP and LCP pulses.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149339065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Nonlinear Rayleigh Taylor instability and soliton formation in multi-ion magnetoplasma: implications for equatorial plasma bubbles","authors":"Haiqa N. Dodhy,&nbsp;Arshad M. Mirza,&nbsp;Samra Naseer,&nbsp;B. Ramzan","doi":"10.1140/epjd/s10053-026-01274-0","DOIUrl":"10.1140/epjd/s10053-026-01274-0","url":null,"abstract":"&lt;p&gt;In a multi-ion magnetoplasma with two different ion species (p and q) and kappa-distributed electrons, the Rayleigh–Taylor (RT) instability, a fundamental plasma instability causing equatorial plasma bubbles (EPBs) in the ionospheric F-region, is examined. The dispersion relation for electrostatic perturbations in a density-stratified plasma under gravity is derived using a linear fluid model. In line with the susceptibility of EPB occurrence to bottomside F-region preconditioning documented during the 2022 Tonga volcanic eruption and the July 2022 geomagnetic storm, the unstable threshold and growth-rate curve fluctuate systematically with the inverse density scale length. By using the reductive perturbation method to extend to the nonlinear regime, we obtain a Korteweg–de Vries (KdV) equation whose soliton solutions show amplitudes and widths that are sensitive to plasma parameters, such as the kappa index and ion mass ratio. Numerical results demonstrate that ion composition and electron superthermality can substantially modify the amplitude, width, and localization of the weakly nonlinear structures. A distinguishing feature of the present study is the treatment of composition-dependent ion inertia and a non-Maxwellian electron response within one linear-to-weakly nonlinear framework, together with an explicit parameter set that permits numerical reproduction of the plotted branches. The resulting dependencies provide reduced-order diagnostics for interpreting composition-sensitive structures measured by satellites, ionosondes, airglow imagers, coherent radars, and Global Navigation Satellite System receivers. They can also be used as benchmarks for multi-ion ionospheric simulations and as physically interpretable inputs to EPB occurrence and scintillation-risk studies. The one-dimensional solitary structures are, therefore, presented as local nonlinear plasma diagnostics rather than as complete models of mature, three-dimensional plasma bubbles.&lt;/p&gt;&lt;p&gt;In this article we obtain a Korteweg–de Vries (KdV) equation whose soliton solutions show amplitudes and widths that are sensitive to the following plasma parameters such as: Kappa index, Ion to mass ratio, Numerical results demonstrate that ion composition and electron super thermality can substantially modify the amplitude, width, and localization of the weakly nonlinear structures as shown in the below figure. Fig Shows Normalized solitary-wave profiles at &lt;span&gt;(m_p/m_q=16)&lt;/span&gt; for &lt;span&gt;(kappa =3)&lt;/span&gt;, &lt;span&gt;(kappa =5)&lt;/span&gt;, and the Maxwellian limit, with &lt;span&gt;(alpha _p=0.90)&lt;/span&gt;, &lt;span&gt;(alpha _q=0.10)&lt;/span&gt;, and &lt;span&gt;(U=0.1)&lt;/span&gt;. The curves have smooth, sharp peaks and use solid lines throughout. A distinguishing feature of the present study is the treatment of composition-dependent ion inertia and a non-Maxwellian electron response within one linear-to-weakly nonlinear framework, together with an explicit parameter set that permits numerical reproduction of the plotte","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Optical offset frequency switching using quantum interference","authors":"Arpan Adak,&nbsp;Ayan Ray","doi":"10.1140/epjd/s10053-026-01261-5","DOIUrl":"10.1140/epjd/s10053-026-01261-5","url":null,"abstract":"<div><p>In this experimental work, we address the issue of quantum interference-assisted optical offset frequency switching through a combination of ladder <span>(5S_{1/2} mathop{longrightarrow}limits_{{780nm}}^{}5P_{3/2} mathop{longrightarrow}limits_{{776nm}}^{}5D_{5/2})</span> + Vee (<span>(5S_{1/2} mathop{longrightarrow}limits_{{780nm}}^{}5P_{3/2})</span>) connections in a Doppler-broadened medium of Rb atoms using three excitation fields in the first part of the study. The system exhibits electromagnetically induced transparency. However, ultra-narrow electromagnetically induced absorption appears as a fine structure within the transparency lineshape when the Vee system is reduced to a degenerate two-level connection by addressing 5S_1/2(F=2) →5P_3/2(F^/=3) cyclic transition. The blue fluorescence due to the decay of atoms through the channel <span>(5D_{5/2} mathop{longrightarrow}limits_{{5.2mu m}}^{}6P_{3/2} mathop{longrightarrow}limits_{{420nm}}^{}5S_{1/2})</span>, indicating the double resonance optical pumping signal starts to get weakened under the influence of Vee-type electromagnetically induced transparency, compared to the same obtained under a pure ladder system. However, the blue light signal becomes almost obscured in the current atom–field picture when the electromagnetically induced absorption signal appears around the closed transition F=2→F^/=3. Very high extinction ratio of blue light at this particular condition paves the way for offset frequency switching at 420 nm by modulating the intensity of one of the excitation channels, satisfying a two-level double-degenerate connection in the 5S→5P hyperfine manifold. In the second part of the investigation, we used phase-correlated beams from a single laser to execute degenerate two-level coupling and left the third laser connecting the 5P→5D transition domain intact. By switching ON and OFF one of the near infrared (780 nm), we obtain switching in the blue fluorescence at 420 nm, thereby establishing offset frequency switching. This may lead to important technical applications like obtaining higher modulation depth in coherence-assisted intensity switching, logic gate construction, etc., in the field of optical communication.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Investigation of pyroelectric properties of ceramic materials","authors":"M. Ali,&nbsp;P. Karataev,&nbsp;V. Harutyunyan,&nbsp;V. Kocharyan,&nbsp;H. Alexanyan,&nbsp;A. Muradyan,&nbsp;N. Sargsyan,&nbsp;A. Aramyan,&nbsp;V. Margaryan,&nbsp;A. Oleinik,&nbsp;A. Kubankin","doi":"10.1140/epjd/s10053-026-01269-x","DOIUrl":"10.1140/epjd/s10053-026-01269-x","url":null,"abstract":"<div><p>This work presents a systematic investigation of the pyroelectric properties of ceramic materials synthesised in Armenia and evaluated as alternatives to conventional single-crystal pyroelectrics. A series of ceramic samples were fabricated via solid-state reaction. Pyroelectric performance was examined under controlled periodic thermal excitation at a frequency of 2 mHz, and the resulting current response was recorded using a low-noise measurement system. The measured pyroelectric coefficients reached values up to 31.5 <span>(pm )</span> 6.2 nC/cm².^oC, exceeding those typically reported for lithium tantalate and lithium niobate under comparable conditions. The measured pyroelectric current amplitude changed with the applied thermal modulation frequency. The materials exhibited stable and repeatable signals over multiple thermal cycles, indicating good thermal and electrical stability. This research also highlights the thermoelectric energy conversion potential of these materials. The ability to harvest waste heat from ambient sources and convert it into usable electrical energy presents a valuable opportunity for sustainable power generation. The combination of high pyroelectric coefficients, dynamic response, and scalable ceramic processing suggests that these materials are promising candidates for pyroelectric X-ray generation technologies and may also have potential for future thermally driven energy-harvesting applications.</p><h3>Graphic Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>Pyroelectric response of ceramic materials, illustrating temperature-dependent current, surface polarisation, and electron acceleration under vacuum, highlighting their potential as scalable alternatives to LiTaO₃ single crystals</p></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Leggett–Garg inequality and quantum block coherence of a Bose–Einstein condensate in a double-well potential","authors":"Qiang Zheng","doi":"10.1140/epjd/s10053-026-01266-0","DOIUrl":"10.1140/epjd/s10053-026-01266-0","url":null,"abstract":"<p>The Leggett–Garg inequality (LGI) was proposed to detect the non-classical temporal correlations in quantum system. This paper investigates a four-time LGI for a Bose–Einstein condensate in a double-well potential. Inspired by the work of Sakamoto et al. (PRA, 111, L021302), we demonstrate that the correlation functions in the LGI can be constructed directly within the decoherent history framework. Moreover, we find that the LGI violation depends not only on the dynamical phase of the system, but also on the specific choice of the measurement operator. In addition, we propose a quantum coherence framework to interpret the observed violation pattern. For the cases considered here, a sharp change in the difference of quantum block coherence may serve as an indicator for the LGI violation.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149234677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Basis-independent coherence dynamics of tripartite states under pure dephasing","authors":"Sovik Roy,&nbsp;Abhijit Mandal","doi":"10.1140/epjd/s10053-026-01272-2","DOIUrl":"10.1140/epjd/s10053-026-01272-2","url":null,"abstract":"<p>Quantum coherence is a fundamental quantum resource whose preservation under environmental interactions is essential for quantum information processing. While most studies have focused on basis-dependent coherence measures, the dynamics of intrinsic coherence quantified by basis-independent measures remain largely unexplored. In this work, we investigate the dynamics of basis-independent quantum coherence for several representative tripartite pure and mixed states subjected to local and common dephasing environments in both Markovian and non-Markovian regimes. We show that Markovian local dephasing leads to state-dependent coherence degradation, whereas collective dephasing significantly enhances coherence preservation through decoherence-free sectors. More importantly, non-Markovian environments give rise to nearly frozen coherence dynamics for both pure and mixed states, demonstrating the remarkable robustness of intrinsic coherence against the dephasing environment. A comparison with the measure of relative entropy of coherence reveals that the basis-independent coherence measure exhibits substantially greater resilience and qualitatively different dynamical behaviour than its basis-dependent counterpart. These results provide new insights into the preservation of intrinsic multipartite coherence in open quantum systems and highlight basis-independent coherence as a robust quantum resource for realistic noisy quantum technologies.</p><p>Schematic overview of basis-independent coherence dynamics for tripartite pure and mixed quantum states under local and common dephasing environments, highlighting state-dependent coherence degradation in Markovian regimes and the near-freezing of coherence in non-Markovian regimes.</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Magnetic-flux-controlled exceptional curve in a SWCNT microtoroid","authors":"Fang-Yu Hong","doi":"10.1140/epjd/s10053-026-01268-y","DOIUrl":"10.1140/epjd/s10053-026-01268-y","url":null,"abstract":"<p>We develop a microscopic theory for realizing flux-programmable exceptional-curve dynamics in a hybrid platform composed of a single-walled carbon nanotube (SWCNT) microtoroid and a nearby nitrogen-vacancy (NV) center. The Aharonov–Bohm flux shifts the two counterpropagating chiral cavity modes in opposite directions, while the chiral NV coupling generates directional mode conversion. By adiabatically eliminating the NV excited state in the dispersive regime, we derive flux-dependent nonreciprocal couplings <span>(J_{12}(Phi )=J_0+alpha _JPhi /Phi _0)</span> and <span>(J_{21}(Phi )=J_0-alpha _JPhi /Phi _0)</span>, which lead to an effective non-Hermitian two-mode Hamiltonian supporting an exceptional point. We demonstrate that while the exact exceptional curve requires simultaneous tuning of the coherent coupling and magnetic flux, a minimum-splitting trajectory tracked via a single flux sweep closely approaches this non-Hermitian degeneracy, manifesting itself in the transmission spectrum through mode coalescence, linewidth bifurcation, and collapse of the doublet resonance. These results provide a concrete microscopic route for engineering and probing exceptional-curve dynamics in chiral SWCNT-based quantum photonic devices.</p><p>Magnetic-flux-controlled exceptional curve in a SWCNT microtoroidMagnetic-flux-controlled exceptional curve in a SWCNT microtoroid</p>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Design of an X-band low-magnetic field high-power microwave radiation source based on the synergistic design of cascaded bunching cavities and a non-uniform output cavity","authors":"Tengfang Wang,&nbsp;Yiming Zhong,&nbsp;Ziyuan Chi,&nbsp;Jinchuan Ju,&nbsp;Wei Zhang,&nbsp;Zihan Li,&nbsp;Tianzhen Zhao,&nbsp;Jiyao Di","doi":"10.1140/epjd/s10053-026-01260-6","DOIUrl":"10.1140/epjd/s10053-026-01260-6","url":null,"abstract":"<div><p>The klystron amplifier driven by an intense relativistic electron beam (IREB) is a crucial technological approach for generating high-power microwave (HPM) radiation. However, a fundamental conflict exists between low-magnetic-field operation and high-power output: increasing the radiation power requires enhancing the beam power and modulation depth, which imposes stringent demands on both the guiding magnetic field strength and the device’s power handling capacity. To address this conflict, this paper optimizes the design of a coaxial multi-beam relativistic klystron amplifier by focusing on the beam-wave interaction process between the IREB and the high-frequency structure. Through the synergistic design of cascaded single-gap bunching cavities and a non-uniform output cavity, simultaneous improvements in electron beam modulation depth and microwave extraction efficiency are achieved. Three-dimensional PIC simulation results show that under the conditions of an injection power of 19.7 kW, a guiding magnetic field of 0.37 T, a beam voltage of 780 kV, and a beam current of 13 kA, the device generates HPM radiation with an output power of 3.97 GW, an efficiency of 39.2%, and a gain of approximately 53 dB. Parameter sensitivity analyses demonstrate typical amplifier characteristics and stable operation under low magnetic field conditions. The results offer a potential new technical path for the development of compact HPM radiation sources.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":789,"journal":{"name":"The European Physical Journal D","volume":"80 10","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}