物理与天体物理最新文献

{"title":"3 kV fully vertical β-Ga2O3 junction termination extension Schottky barrier diode with sputtered p-GaN","authors":"Qingyuan Chang, Bin Hou, Ling Yang, Mao Jia, Youjun Zhu, Mei Wu, Meng Zhang, Qing Zhu, Hao Lu, Jiarui Xu, Chunzhou Shi, Jiale Du, Qian Yu, Mengdi Li, Xu Zou, Haolun Sun, Xiaohua Ma, Yue Hao","doi":"10.1063/5.0243637","DOIUrl":"https://doi.org/10.1063/5.0243637","url":null,"abstract":"In this work, we present the fabrication of a fully vertical β-Ga2O3 Schottky barrier diode with junction termination extension (JTE-SBD) utilizing a p-GaN layer produced by sputtering, offering a solution to the absence of p-Ga2O3 materials. The p-GaN/n-Ga2O3 JTE-SBD demonstrates a turn-on voltage (Von) of 0.8 V, a specific on-resistance (Ron,sp) of 6.15 mΩ·cm2, an ideality factor (n) of 1.24, a breakdown voltage of 3 kV, and a Baliga's Figure of Merit of 1.46 GW/cm2. The current–voltage–temperature (I–V–T) testing has confirmed a transition in the dominant leakage mechanisms from the Poole–Frenkel mechanism to variable-range hopping.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 domain engineering for quantum technologies","authors":"Tim F. Weiss, Alberto Peruzzo","doi":"10.1063/5.0223013","DOIUrl":"https://doi.org/10.1063/5.0223013","url":null,"abstract":"The continuously growing effort toward developing real-world quantum technological applications has come to demand an increasing amount of flexibility from its respective platforms. This review presents a highly adaptable engineering technique for photonic quantum technologies based on the artificial structuring of the material nonlinearity. This technique, while, in a simple form, already featured across the full breadth of photonic quantum technologies, has undergone significant development over the last decade, now featuring advanced, aperiodic designs. This review gives an introduction to the three-wave-mixing processes lying at the core of this approach and illustrates, on basis of the underlying quantum-mechanical description, how they can artificially be manipulated to engineer the corresponding photon characteristics. It then describes how this technique can be employed to realize a number of very different objectives, which are expected to find application across the full range of photonic quantum technologies, and presents a summary of the research done toward these ends to date.","PeriodicalId":8200,"journal":{"name":"Applied physics reviews","volume":"52 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Calculation Electronic Structure and Topological Properties of A15-Type Mo3Si Based on First-Principles Predictions","authors":"Hanqi Zhou,&nbsp;Li Zhang","doi":"10.1007/s10948-025-06929-4","DOIUrl":"10.1007/s10948-025-06929-4","url":null,"abstract":"<div><p>Superconductors with the A15 structure are prototypical type II s-wave superconductors which have generated considerable interest in early superconducting material history. However, the topological properties of the electronic structure remain unnoticed. In this study, we used first-principles calculations based on density-functional theory to investigate the structure, electronic properties, surface states, and topological properties of A15-type Mo₃Si compounds. The thermodynamic properties show that Mo₃Si exhibits thermodynamic stability, and its band structure and density of states indicate that Mo₃Si is a metallic compound. Meanwhile, the next calculations show the existence of potential topological properties of Mo₃Si, with suspected Dirac cones and many multiple concatenation points with linear dispersions in the vicinity of the Fermi energy level. In addition, the study of edge states suggests that topological surface states are highly likely to exist in Mo₃Si, revealing its potential applications in electron transport and quantum information processing. Its unique structural properties suggest that Mo₃Si is highly likely to be a topological material with broad potential applications.</p></div>","PeriodicalId":669,"journal":{"name":"Journal of Superconductivity and Novel Magnetism","volume":"38 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143373259","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":"Efficient Hamiltonian encoding algorithms for extracting quantum control mechanism as interfering pathway amplitudes in the Dyson series","authors":"Erez Abrams, Michael Kasprzak, Gaurav Bhole, Tak-San Ho, Herschel Rabitz","doi":"10.22331/q-2025-02-10-1626","DOIUrl":"https://doi.org/10.22331/q-2025-02-10-1626","url":null,"abstract":"Hamiltonian encoding is a methodology for revealing the mechanism behind the dynamics governing controlled quantum systems. In this paper, following Mitra and Rabitz [9], we define mechanism via pathways of eigenstates that describe the evolution of the system, where each pathway is associated with a complex-valued amplitude corresponding to a term in the Dyson series. The evolution of the system is determined by the constructive and destructive interference of these pathway amplitudes. Pathways with similar attributes can be grouped together into pathway classes. The amplitudes of pathway classes are computed by modulating the Hamiltonian matrix elements and decoding the subsequent evolution of the system rather than by direct computation of the individual terms in the Dyson series. The original implementation of Hamiltonian encoding was computationally intensive and became prohibitively expensive in large quantum systems. This paper presents two new encoding algorithms that calculate the amplitudes of pathway classes by using techniques from graph theory and algebraic topology to exploit patterns in the set of allowed transitions, greatly reducing the number of matrix elements that need to be modulated. These new algorithms provide an exponential decrease in both computation time and memory utilization with respect to the Hilbert space dimension of the system. To demonstrate the use of these techniques, they are applied to two illustrative state-to-state transition problems.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"85 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Quantum error mitigation for Fourier moment computation","authors":"Oriel Kiss, Michele Grossi, Alessandro Roggero","doi":"10.1103/physrevd.111.034504","DOIUrl":"https://doi.org/10.1103/physrevd.111.034504","url":null,"abstract":"Hamiltonian moments in Fourier space—expectation values of the unitary evolution operator under a Hamiltonian at different times—provide a convenient framework to understand quantum systems. They offer insights into the energy distribution, higher-order dynamics, response functions, correlation information, and physical properties. This paper focuses on the computation of Fourier moments within the context of a nuclear effective field theory on superconducting quantum hardware. The study integrates echo verification and noise renormalization into Hadamard tests using control reversal gates. These techniques, combined with purification and error suppression methods, effectively address quantum hardware decoherence. The analysis, conducted using noise models, reveals a significant reduction in noise strength by two orders of magnitude. Moreover, quantum circuits involving up to 266 gates over five qubits demonstrate high accuracy under these methodologies when run on IBM superconducting quantum devices. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20167,"journal":{"name":"Physical Review D","volume":"12 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 cold neutral medium in filaments at high Galactic latitudes","authors":"P. M. W. Kalberla","doi":"10.1051/0004-6361/202452771","DOIUrl":"https://doi.org/10.1051/0004-6361/202452771","url":null,"abstract":"<i>Context.<i/> The H I distribution at high Galactic latitudes has been found to be filamentary and closely related to the far infrared (FIR) in caustics with coherent velocity structures. These structures trace the orientation of magnetic field lines.<i>Aims.<i/> Recent absorption observations with the Australian SKA Pathfinder Telescope have led to major improvements in the understanding of the physical properties of the cold neutral medium (CNM) at high Galactic latitudes. We use these results to explore how far the physical state of the CNM may be related with caustics in H I and FIR.<i>Methods.<i/> We traced filamentary FIR and H I structures and probed the absorption data for coincidences in position and velocity.<i>Results.<i/> Of the absorption positions, 57% are associated with known FIR/H I caustics, filamentary dusty structures with a coherent velocity field. The remaining part of the absorption sample is coincident in position and velocity with genuine H I filaments that are closely related to the FIR counterparts. Thus, within the current sensitivity limitations, all the positions with H I absorption lines are associated with filamentary structures in FIR and/or H I. We summarize the physical parameters for the CNM along filaments in the framework of filament velocities <i>v<i/><sub>fil<sub/> that have been determined from a Hessian analysis of FIR and H I emission data. Velocity deviations between absorption components and filament velocities are due to local turbulence, and we determine for the observed CNM an average turbulent velocity dispersion of 2.48 < <i>δ<i/><i>v<i/><sub>turb<sub/> < 3.9 km s<sup>−1<sup/>. The CNM has a mean turbulent Mach number of <i>M<i/><sub>t<sub/> = 3.4 ± 1.6 km s<sup>−1<sup/>.<i>Conclusions.<i/> Most, if not all, of the CNM in the diffuse interstellar medium at high Galactic latitudes is located in filaments, identified as caustics with the Hessian operator.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"79 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Transit-timing variations in the AU Mic system observed with CHEOPS★","authors":"Á. Boldog, Gy. M. Szabó, L. Kriskovics, L. Borsato, D. Gandolfi, M. Lendl, M. N. Günther, A. Heitzmann, T. G. Wilson, A. Brandeker, Z. Garai, Y. Alibert, R. Alonso, T. Bárczy, D. Barrado Navascues, S. C. C. Barros, W. Baumjohann, W. Benz, N. Billot, C. Broeg, A. Collier Cameron, A. C. M. Correia, Sz. Csizmadia, P. E. Cubillos, M. B. Davies, M. Deleuil, A. Deline, O. D. S. Demangeon, B.-O. Demory, A. Derekas, B. Edwards, J. A. Egger, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, K. Gazeas, M. Gillon, M. Güdel, P. Guterman, Ch. Helling, K. G. Isaak, L. L. Kiss, E. Kopp, J. Korth, K. W. F. Lam, J. Laskar, A. Lecavelier des Etangs, A. Luntzer, D. Magrin, G. Mantovan, L. Marafatto, P. F. L. Maxted, B. Merín, C. Mordasini, M. Munari, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, K. Poppenhaeger, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, M. Rieder, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M. S. Smith, S. G. Sousa, R. Southworth, M. Stalport, S. Sulis, S. Udry, S. Ulmer-Moll, V. Van Grootel, J. Venturini, E. Villaver, N. A. Walton, T. Zingales","doi":"10.1051/0004-6361/202452699","DOIUrl":"https://doi.org/10.1051/0004-6361/202452699","url":null,"abstract":"<i>Context<i/>. AU Mic is a very active M dwarf star with an edge-on debris disk and two known transiting sub-Neptunes with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs) that are caused by the gravi tational interaction between the bodies in the system.<i>Aims<i/>. Using photometrical observations taken with the CHaracterizing ExOPlanet Satellite (CHEOPS), we aim to constrain the plan etary radii, the orbital distances, and the periods of AU Mic b and c. Furthermore, our goal is to determine the superperiod of the TTVs for AU Mic b and to update the transit ephemeris for both planets. Additionally, based on the perceived TTVs, we study the possible presence of a third planet in the system.<i>Methods<i/>. We conducted ultra-high precision photometric observations with CHEOPS in 2022 and 2023. We used Allesfitter to fit the planetary transits and to constrain the planetary and orbital parameters. We combined our new measurements with results from previous years to determine the periods and amplitudes of the TTVs. We applied dynamical modelling based on TTV measurements from the 2018–2023 period to reconstruct the perceived variations.<i>Results<i/>. We found that the orbital distances and periods for AU Mic b and c agree with the results from previous works. However, the values for the planetary radii deviate slightly from previous values, which we attribute to the effect of spots on the stellar surface. AU Mic c showed very strong TTVs, with transits that occurred ∼80 minutes later in 2023 than in 2021. Through a dynamical analysis of the system, we found that the observed TTVs can be explained by a third planet with an orbital period of ∼12.6 days and a mass of 0.203<sub>−0.024<sub/><sup>+0.022<sup/> M<sub>⊕<sub/>. We explored the orbital geometry of the system and found that AU Mic c has a misaligned retrograde orbit. The limited number of AU Mic observations prevented us from determining the exact dynamical configuration and planetary parameters. Further monitoring of the system with CHEOPS might help to improve these results.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"51 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"High efficiency and tunable second harmonic generation in electro-optic Q-modulated metasurface with etchless lithium niobate","authors":"Yuejian Jiao ,&nbsp;Mengyuan Liu ,&nbsp;Xiaozhuo Qi ,&nbsp;Lei Xu ,&nbsp;Guoquan Zhang","doi":"10.1016/j.optcom.2025.131585","DOIUrl":"10.1016/j.optcom.2025.131585","url":null,"abstract":"<div><div>Second harmonic generation (SHG) at nanoscales have broad applications in integrated optoelectronic devices. In this paper, we numerically demonstrate highly efficient and electrically tunable SHG in metasurface with etchless lithium niobate (LN), based on symmetry-protected bound states in the continuum (BIC). Since the excellent electro-optic (EO) properties of LN, the symmetry of structural refractive index can be very slightly broken under an external voltage, resulting in the excitation of quasi-BIC with an ultrahigh quality factor (<span><math><mi>Q</mi></math></span> factor). When asymmetry parameter is set to be <span><math><mrow><mi>Δ</mi><mi>n</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>001</mn></mrow></math></span>, a quasi-BIC with <span><math><mi>Q</mi></math></span> factor as high as <span><math><mrow><mn>5</mn><mo>.</mo><mn>4</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>7</mn></mrow></msup></mrow></math></span> magnitude is excited, achieving 1.2% conversion efficiency of SHG under 0.1 kW/cm<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> input intensity. We also show that the <span><math><mi>Q</mi></math></span> factor and conversion efficiency can be actively and finely modulated by tuning asymmetry factor <span><math><mrow><mi>Δ</mi><mi>n</mi></mrow></math></span> based on EO effects of LN. Our work provides a feasible idea to excite quasi-BIC with ultrahigh and accurately tunable <span><math><mi>Q</mi></math></span> factor, and paves a way in designing electrically tunable ultracompact light sources.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"579 ","pages":"Article 131585"},"PeriodicalIF":2.2,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379086","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":"Euclid preparation","authors":"N. Tessore, B. Joachimi, A. Loureiro, A. Hall, G. Cañas-Herrera, I. Tutusaus, N. Jeffrey, K. Naidoo, J. D. McEwen, A. Amara, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, S. Bardelli, F. Bernardeau, D. Bonino, E. Branchini, M. Brescia, J. Brinchmann, A. Caillat, S. Camera, V. Capobianco, C. Carbone, V. F. Cardone, J. Carretero, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, A. Da Silva, H. Degaudenzi, G. De Lucia, J. Dinis, F. Dubath, C. A. J. Duncan, X. Dupac, S. Dusini, M. Farina, S. Farrens, F. Faustini, S. Ferriol, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, W. Gillard, B. Gillis, C. Giocoli, P. Gómez-Alvarez, A. Grazian, F. Grupp, L. Guzzo, S. V. H. Haugan, H. Hoekstra, W. Holmes, F. Hormuth, A. Hornstrup, P. Hudelot, K. Jahnke, M. Jhabvala, E. Keihänen, S. Kermiche, A. Kiessling, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, E. Maiorano, O. Mansutti, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. Massey, E. Medinaceli, S. Mei, M. Melchior, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, J. J. Mohr, M. Moresco, B. Morin, L. Moscardini, E. Munari, R. Nakajima, S.-M. Niemi, C. Padilla, S. Paltani, F. Pasian, K. Pedersen, W. J. Percival, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, F. Raison, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, E. Rossetti, R. Saglia, Z. Sakr, A. G. Sánchez, D. Sapone, B. Sartoris, M. Schirmer, P. Schneider, T. Schrabback, A. Secroun, G. Seidel, M. Seiffert, S. Serrano, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, I. Tereno, R. Toledo-Moreo, F. Torradeflot, L. Valenziano, T. Vassallo, Y. Wang, J. Weller, G. Zamorani, E. Zucca, A. Biviano, M. Bolzonella, A. Boucaud, E. Bozzo, C. Burigana, M. Calabrese, D. Di Ferdinando, J. A. Escartin Vigo, F. Finelli, J. Gracia-Carpio, S. Matthew, N. Mauri, A. Pezzotta, M. Pöntinen, V. Scottez, A. Spurio Mancini, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, A. Balaguera-Antolinez, M. Ballardini, D. Benielli, A. Blanchard, L. Blot, H. Böhringer, S. Borgani, S. Bruton, R. Cabanac, A. Calabro, B. Camacho Quevedo, A. Cappi, F. Caro, C. S. Carvalho, T. Castro, K. C. Chambers, A. R. Cooray, S. de la Torre, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, H. Dole, S. Escoffier, A. G. Ferrari, P. G. Ferreira, I. Ferrero, A. Finoguenov, A. Fontana, F. Fornari, L. Gabarra, K. Ganga, J. García-Bellido, T. Gasparetto, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, C. M. Gutierrez, W. G. Hartley, H. Hildebrandt, J. Hjorth, A. Jimenez Muñoz, S. Joudaki, J. J. E. Kajava, V. Kansal, D. Karagiannis, C. C. Kirkpatrick, S. Kruk, F. Lacasa, M. Lattanzi, A. M. C. Le Brun, J. Le Graet, L. Legrand, J. Lesgourgues, T. I. Liaudat, J. Macias-Perez, M. Magliocchetti, F. Mannucci, R. Maoli, J. Martín-Fleitas, C. J. A. P. Martins, L. Maurin, R. B. Metcalf, M. Miluzio, P. Monaco, A. Montoro, C. Moretti, G. Morgante, C. Murray, S. Nadathur, N. A. Walton, L. Patrizii, V. Popa, D. Potter, P. Reimberg, I. Risso, P.-F. Rocci, R. P. Rollins, M. Sahlén, E. Sarpa, A. Schneider, M. Sereno, P. Simon, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Toft, S. Tosi, A. Troja, M. Tucci, C. Valieri, J. Valiviita, D. Vergani, G. Verza, P. Vielzeuf, M. L. Brown, E. Sellentin","doi":"10.1051/0004-6361/202452018","DOIUrl":"https://doi.org/10.1051/0004-6361/202452018","url":null,"abstract":"In this paper we present the framework for measuring angular power spectra in the <i>Euclid<i/> mission. The observables in galaxy surveys, such as galaxy clustering and cosmic shear, are not continuous fields, but discrete sets of data, obtained only at the positions of galaxies. We show how to compute the angular power spectra of such discrete data sets, without treating observations as maps of an underlying continuous field that is overlaid with a noise component. This formalism allows us to compute the exact theoretical expectations for our measured spectra, under a number of assumptions that we track explicitly. In particular, we obtain exact expressions for the additive biases (‘shot noise’) in angular galaxy clustering and cosmic shear. For efficient practical computations, we introduce a spin-weighted spherical convolution with a well-defined convolution theorem, which allows us to apply exact theoretical predictions to finite-resolution maps, including <i>HEALPix<i/>. When validating our methodology, we find that our measurements are biased by less than 1% of their statistical uncertainty in simulations of <i>Euclid<i/>’s first data release.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"55 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Repeated pattern of γ-ray flares in the blazar PKS 1502+106 coincident with the IC190730A neutrino event","authors":"Dmitry Blinov, Polina Novikova","doi":"10.1051/0004-6361/202453361","DOIUrl":"https://doi.org/10.1051/0004-6361/202453361","url":null,"abstract":"<i>Context.<i/> It has been demonstrated that at least 10% of the brightest blazars in the fourth Fermi-LAT catalog of <i>γ<i/>-ray sources exhibit repeating patterns of <i>γ<i/>-ray flares. These events may be associated with the presence of a non-uniform sheath surrounding a fast jet spine in some blazars. Theoretical models suggest that such a sheath could facilitate neutrino production in these structured jets.<i>Aims.<i/> We aim to test the marginal statistical evidence previously reported for a connection between repeating patterns of <i>γ<i/>-ray flares in blazars and high-energy neutrino events that are positionally consistent with these sources.<i>Methods.<i/> We identified a repeating pattern of flares in the <i>γ<i/>-ray light curve of the blazar PKS 1502+106, which lies within the 50% uncertainty region of the IC190730A neutrino candidate event. This occurrence is combined with two other high-energy (≥200 TeV) neutrino events from ICECAT-1, which arrived in both positional and temporal coincidence with two blazars exhibiting ongoing repeating flare patterns. We conducted a Monte Carlo simulation to evaluate the likelihood of accidental coincidences between the repeating flare patterns and neutrino events, accounting for potential unrecognized systematic uncertainties in the arrival directions of the ICECAT-1 events.<i>Results.<i/> Our findings indicate the probability of a random coincidence, in both time and arrival direction for three high-energy neutrino candidates and three blazars with ongoing recurring patterns of <i>γ<i/>-ray flares, is 1.56 × 10<sup>−3<sup/> (3.2<i>σ<i/>).","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"31 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}