Pub Date : 2026-02-10DOI: 10.22331/q-2026-02-10-2002
Roozbeh Bassirian, Adam Bouland, Bill Fefferman, Sam Gunn, Avishay Tal
Certified randomness has a long history in quantum information, with many potential applications. Recently Aaronson and Hung proposed a novel public certified randomness protocol based on existing random circuit sampling (RCS) experiments. The security of their protocol, however, relies on non-standard complexity-theoretic conjectures which were not previously studied in the literature.
Inspired by this work, we study certified randomness in the quantum random oracle model (QROM). We show that quantum Fourier Sampling can be used to define a publicly verifiable certified randomness protocol with black-box security without any computational assumptions. In addition to giving a certified randomness protocol in the QROM, our work can also be seen as supporting Aaronson and Hung's conjectures for RCS-based randomness generation, as our protocol is in some sense the "black-box version" of Aaronson and Hung's protocol. In further support of Aaronson and Hung's proposal, we prove a Fourier Sampling version of Aaronson and Hung's conjecture by extending Raz and Tal's separation of BQP vs PH.
Our work complements the subsequent certified randomness protocol of Yamakawa and Zhandry (2022) in the QROM. Whereas the security of that protocol relied on the Aaronson-Ambainis conjecture, ours does not rely on any computational assumption – at the expense of requiring exponential-time classical verification. Our protocol also has a simple heuristic implementation.
{"title":"On Certified Randomness from Fourier Sampling or Random Circuit Sampling","authors":"Roozbeh Bassirian, Adam Bouland, Bill Fefferman, Sam Gunn, Avishay Tal","doi":"10.22331/q-2026-02-10-2002","DOIUrl":"https://doi.org/10.22331/q-2026-02-10-2002","url":null,"abstract":"Certified randomness has a long history in quantum information, with many potential applications. Recently Aaronson and Hung proposed a novel public certified randomness protocol based on existing random circuit sampling (RCS) experiments. The security of their protocol, however, relies on non-standard complexity-theoretic conjectures which were not previously studied in the literature.<br/>\u0000<br/> Inspired by this work, we study certified randomness in the quantum random oracle model (QROM). We show that quantum Fourier Sampling can be used to define a publicly verifiable certified randomness protocol with black-box security without any computational assumptions. In addition to giving a certified randomness protocol in the QROM, our work can also be seen as supporting Aaronson and Hung's conjectures for RCS-based randomness generation, as our protocol is in some sense the \"black-box version\" of Aaronson and Hung's protocol. In further support of Aaronson and Hung's proposal, we prove a Fourier Sampling version of Aaronson and Hung's conjecture by extending Raz and Tal's separation of BQP vs PH.<br/>\u0000<br/> Our work complements the subsequent certified randomness protocol of Yamakawa and Zhandry (2022) in the QROM. Whereas the security of that protocol relied on the Aaronson-Ambainis conjecture, ours does not rely on any computational assumption – at the expense of requiring exponential-time classical verification. Our protocol also has a simple heuristic implementation.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"45 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146747","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}
Evgeniy S. Lotkov, Aleksandr S. Baburin, Ali Sh. Amiraslanov, Eugeny D. Chubchev, Alexander V. Dorofeenko, Eugeny S. Andrianov, Evgeny V. Sergeev, Kirill A. Buzaverov, Sergey S. Avdeev, Aleksey B. Kramarenko, Sergey V. Bukatin, Victor I. Polozov, Olga S. Sorokina, Daria P. Kulikova, Alexander V. Baryshev, Ilya A. Ryzhikov, Yuri V. Panfilov, Ilya A. Rodionov
Silicon nitride (SiN) is currently the most prominent platform for photonics in the visible and near-IR wavelength bandwidth. However, realizing fast electro-optic modulators, the key components of any integrated optics platform remain challenging in SiN. Recently, transparent conductive oxides have emerged as a promising platform for photonic integrated circuits. In this work, we take an important step toward combining the advantages of both platforms, reporting for the high-speed indium tin oxide electro-optic modulators based on silicon nitride waveguides. We demonstrate a bandwidth higher than 1 GHz, 9.3-μm-length active element, and an insertion loss of 5.7 dB for a 300 nm-thickness SiN waveguide platform. Simulation results of optimized device designs indicate that further improvements are possible, offering promising opportunities for silicon nitride photonic integrated circuit platform combined with indium oxide-based layers.
{"title":"Silicon nitride integrated electro-optic absorption modulator","authors":"Evgeniy S. Lotkov, Aleksandr S. Baburin, Ali Sh. Amiraslanov, Eugeny D. Chubchev, Alexander V. Dorofeenko, Eugeny S. Andrianov, Evgeny V. Sergeev, Kirill A. Buzaverov, Sergey S. Avdeev, Aleksey B. Kramarenko, Sergey V. Bukatin, Victor I. Polozov, Olga S. Sorokina, Daria P. Kulikova, Alexander V. Baryshev, Ilya A. Ryzhikov, Yuri V. Panfilov, Ilya A. Rodionov","doi":"10.1063/5.0293940","DOIUrl":"https://doi.org/10.1063/5.0293940","url":null,"abstract":"Silicon nitride (SiN) is currently the most prominent platform for photonics in the visible and near-IR wavelength bandwidth. However, realizing fast electro-optic modulators, the key components of any integrated optics platform remain challenging in SiN. Recently, transparent conductive oxides have emerged as a promising platform for photonic integrated circuits. In this work, we take an important step toward combining the advantages of both platforms, reporting for the high-speed indium tin oxide electro-optic modulators based on silicon nitride waveguides. We demonstrate a bandwidth higher than 1 GHz, 9.3-μm-length active element, and an insertion loss of 5.7 dB for a 300 nm-thickness SiN waveguide platform. Simulation results of optimized device designs indicate that further improvements are possible, offering promising opportunities for silicon nitride photonic integrated circuit platform combined with indium oxide-based layers.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"394 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160557","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}
Pub Date : 2026-02-10DOI: 10.22331/q-2026-02-10-2003
David Layden, Bradley Mitchell, Karthik Siva
Quantum error mitigation techniques mimic noiseless quantum circuits by running several related noisy circuits and combining their outputs in particular ways. How well such techniques work is thought to depend strongly on how noisy the underlying gates are. Weakly-entangling gates, like $R_{ZZ}(theta)$ for small angles $theta$, can be much less noisy than entangling Clifford gates, like CNOT and CZ, and they arise naturally in circuits used to simulate quantum dynamics. However, such weakly-entangling gates are non-Clifford, and are therefore incompatible with two of the most prominent error mitigation techniques to date: probabilistic error cancellation (PEC) and the related form of zero-noise extrapolation (ZNE). This paper generalizes these techniques to non-Clifford gates, and comprises two complementary parts. The first part shows how to effectively transform any given quantum channel into (almost) any desired channel, at the cost of a sampling overhead, by adding random Pauli gates and processing the measurement outcomes. This enables us to cancel or properly amplify noise in non-Clifford gates, provided we can first characterize such gates in detail. The second part therefore introduces techniques to do so for noisy $R_{ZZ}(theta)$ gates. These techniques are robust to state preparation and measurement (SPAM) errors, and exhibit concentration and sensitivity—crucial statistical properties for many experiments. They are related to randomized benchmarking, and may also be of interest beyond the context of error mitigation. We find that while non-Clifford gates can be less noisy than related Cliffords, their noise is fundamentally more complex, which can lead to surprising and sometimes unwanted effects in error mitigation. Whether this trade-off can be broadly advantageous remains to be seen.
{"title":"Theory of quantum error mitigation for non-Clifford gates","authors":"David Layden, Bradley Mitchell, Karthik Siva","doi":"10.22331/q-2026-02-10-2003","DOIUrl":"https://doi.org/10.22331/q-2026-02-10-2003","url":null,"abstract":"Quantum error mitigation techniques mimic noiseless quantum circuits by running several related noisy circuits and combining their outputs in particular ways. How well such techniques work is thought to depend strongly on how noisy the underlying gates are. Weakly-entangling gates, like $R_{ZZ}(theta)$ for small angles $theta$, can be much less noisy than entangling Clifford gates, like CNOT and CZ, and they arise naturally in circuits used to simulate quantum dynamics. However, such weakly-entangling gates are non-Clifford, and are therefore incompatible with two of the most prominent error mitigation techniques to date: probabilistic error cancellation (PEC) and the related form of zero-noise extrapolation (ZNE). This paper generalizes these techniques to non-Clifford gates, and comprises two complementary parts. The first part shows how to effectively transform any given quantum channel into (almost) any desired channel, at the cost of a sampling overhead, by adding random Pauli gates and processing the measurement outcomes. This enables us to cancel or properly amplify noise in non-Clifford gates, provided we can first characterize such gates in detail. The second part therefore introduces techniques to do so for noisy $R_{ZZ}(theta)$ gates. These techniques are robust to state preparation and measurement (SPAM) errors, and exhibit concentration and sensitivity—crucial statistical properties for many experiments. They are related to randomized benchmarking, and may also be of interest beyond the context of error mitigation. We find that while non-Clifford gates can be less noisy than related Cliffords, their noise is fundamentally more complex, which can lead to surprising and sometimes unwanted effects in error mitigation. Whether this trade-off can be broadly advantageous remains to be seen.","PeriodicalId":20807,"journal":{"name":"Quantum","volume":"393 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146748","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}
Pub Date : 2026-02-10DOI: 10.1051/0004-6361/202557598
A. G. M. Pietrow, M. Baratella, I. V. Ilyin, M. Steffen, K. G. Strassmeier
The determination of the solar oxygen abundance remains a central problem in astrophysics because its accuracy is limited not only by models, but also by systematics. While many of these factors have been thoroughly characterized, the effect of the solar activity cycle has remained unexplored so far. Because of its relative strength and accessibility, the O I infrared triplet is typically the primary choice for abundance studies. Previous investigations have shown, however, that abundances inferred from this triplet tend to be higher than expected on active stars, but no such overabundance effect is observed for the much weaker forbidden O I 6300 Å line. This raises the question of whether a similar trend can be found for the Sun. To address this question, we analyzed synoptic disk-integrated Sun-as-a-star datasets of two decades from the FEROS, HARPS-N, PEPSI, and NEID spectrographs with a focus on the infrared triplet (7772, 7774, and 7775 Å) and the forbidden O I 6300 Å line. The excellent signal-to-noise ratio of the PEPSI observations allowed us to detect a weak but significant variation in the equivalent widths of the infrared triplet that corresponds to an abundance difference of about 0.01 dex between activity minimum and maximum. This value is significantly lower than the typical uncertainties on the solar oxygen abundance. No comparable trend is found in the other datasets because the scatter is higher. Based on these results, we conclude that within the typical uncertainties presented in other works, we can assume the inferred solar oxygen abundance to be stable throughout the solar cycle, but that this effect might be significant for other more active stars.
太阳氧丰度的测定仍然是天体物理学中的一个中心问题，因为它的准确性不仅受到模型的限制，而且受到系统学的限制。虽然这些因素中的许多已经被彻底地描述了，但太阳活动周期的影响至今仍未被探索。由于其相对强度和可接近性，O I红外三重态通常是丰度研究的首选。然而，先前的研究表明，从这个三重态推断出的丰度在活跃恒星上往往比预期的要高，但在更弱的O I 6300 Å线上没有观察到这种过剩效应。这就提出了一个问题：太阳是否也有类似的趋势？为了解决这个问题，我们分析了来自FEROS， HARPS-N， PEPSI和NEID光谱仪的20年来太阳作为恒星的综合圆盘数据集，重点关注红外三重态（7772,7774和7775 Å）和禁止的O I 6300 Å线。PEPSI观测的良好信噪比使我们能够探测到红外三重态等效宽度的微弱但显著的变化，对应于活动最小值和最大值之间约0.01指数的丰度差异。这个值明显低于太阳氧丰度的典型不确定度。在其他数据集中没有发现可比较的趋势，因为散点更高。基于这些结果，我们得出结论，在其他工作中提出的典型不确定性中，我们可以假设推断的太阳氧丰度在整个太阳周期中是稳定的，但这种影响可能对其他更活跃的恒星很重要。
{"title":"Does the solar oxygen abundance change over the solar cycle?","authors":"A. G. M. Pietrow, M. Baratella, I. V. Ilyin, M. Steffen, K. G. Strassmeier","doi":"10.1051/0004-6361/202557598","DOIUrl":"https://doi.org/10.1051/0004-6361/202557598","url":null,"abstract":"The determination of the solar oxygen abundance remains a central problem in astrophysics because its accuracy is limited not only by models, but also by systematics. While many of these factors have been thoroughly characterized, the effect of the solar activity cycle has remained unexplored so far. Because of its relative strength and accessibility, the O I infrared triplet is typically the primary choice for abundance studies. Previous investigations have shown, however, that abundances inferred from this triplet tend to be higher than expected on active stars, but no such overabundance effect is observed for the much weaker forbidden O I 6300 Å line. This raises the question of whether a similar trend can be found for the Sun. To address this question, we analyzed synoptic disk-integrated Sun-as-a-star datasets of two decades from the FEROS, HARPS-N, PEPSI, and NEID spectrographs with a focus on the infrared triplet (7772, 7774, and 7775 Å) and the forbidden O I 6300 Å line. The excellent signal-to-noise ratio of the PEPSI observations allowed us to detect a weak but significant variation in the equivalent widths of the infrared triplet that corresponds to an abundance difference of about 0.01 dex between activity minimum and maximum. This value is significantly lower than the typical uncertainties on the solar oxygen abundance. No comparable trend is found in the other datasets because the scatter is higher. Based on these results, we conclude that within the typical uncertainties presented in other works, we can assume the inferred solar oxygen abundance to be stable throughout the solar cycle, but that this effect might be significant for other more active stars.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"46 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153541","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}
Domain-wall skyrmions (DWSks) are topological spin textures confined within magnetic domain walls. These hybrid structures have recently attracted considerable interest due to their combination of advantageous features from both domain walls and skyrmions, including topological protection, low driving-current density, nanoscale size, and ease of read/write operations. Since DWSks are trapped within domain walls, theoretical studies suggest that their Hall motion can be substantially suppressed, enabling highly controllable one-dimensional propagation. However, in practice, when DWSks are driven by an electric current, the domain wall itself is also propelled into motion, which substantially increases the complexity of the dynamical behavior. In this study, we suppress domain wall motion by locally reducing the perpendicular magnetic anisotropy and systematically investigate the motion of DWSks within pinned domain walls. The proposed approach facilitates the design of densely arranged domain wall channels and supports the propagation of multiple DWSks within a single channel, consequently enhancing the integration density of DWSk-based devices. Our findings advance the understanding of DWSk dynamics and offer valuable insights for the development of future spintronic applications.
{"title":"Current-driven dynamics of domain-wall skyrmions in pinned channels","authors":"Xiao-Ping Ma, Xiaoxue Yang, Qi-Shuo Wang, Kangjie Tian, Hongyan Zhang, Zhaochu Luo, Hong-Guang Piao","doi":"10.1063/5.0306099","DOIUrl":"https://doi.org/10.1063/5.0306099","url":null,"abstract":"Domain-wall skyrmions (DWSks) are topological spin textures confined within magnetic domain walls. These hybrid structures have recently attracted considerable interest due to their combination of advantageous features from both domain walls and skyrmions, including topological protection, low driving-current density, nanoscale size, and ease of read/write operations. Since DWSks are trapped within domain walls, theoretical studies suggest that their Hall motion can be substantially suppressed, enabling highly controllable one-dimensional propagation. However, in practice, when DWSks are driven by an electric current, the domain wall itself is also propelled into motion, which substantially increases the complexity of the dynamical behavior. In this study, we suppress domain wall motion by locally reducing the perpendicular magnetic anisotropy and systematically investigate the motion of DWSks within pinned domain walls. The proposed approach facilitates the design of densely arranged domain wall channels and supports the propagation of multiple DWSks within a single channel, consequently enhancing the integration density of DWSk-based devices. Our findings advance the understanding of DWSk dynamics and offer valuable insights for the development of future spintronic applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160237","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}
Rajnarayan De, C. Kar, Kiran Baraik, B. R. Kumar, S. Pradhan
The requirement of substantially higher growth temperature and post-deposition annealing for epitaxial growth of vanadium oxide (VO2) films has always remained a bottleneck for their practical applicability in various thermochromic smart devices. Here, we report epitaxial growth of vanadium oxide (VO2) thin films on sapphire substrates using the reactive gas pulsing technique (RGPT) in conjunction with intense plasma activation facilitated by asymmetric bipolar pulse DC (ABPDC) sputtering. The deposition methodology followed in this work utilizes growth temperature as low as 275 °C as opposed to the substantially higher temperatures (>500 °C) reported in previous works. The process also avoids any post-processing of the films including annealing. The films deposited in RGPT mode show good environmental stability over a long time range using a simple deposition methodology without placing any top barrier layers to stop ageing. Investigation of the semiconductor-to-metal transition (SMT) behavior reveals a very sharp reversible first-order phase transition with sharpness ∼2 °C (very close to bulk single crystals) and switching ratio of ∼1 × 104 achieved with the RGPT mode. The epitaxial relationship of [010]VO2 ǁ [0001]Al2O3 (out-of-plane) and [001]VO2 ǁ [11-20]Al2O3 (in-plane) is established through the measurement of in-plane and out-of-plane microstructural characterization. Overall, this work presents a reliable method for the low temperature growth of epitaxial VO2 thin films with good environmental stability and excellent semiconductor–metal switching performance.
{"title":"Low-temperature growth of environmentally stable epitaxial VO2 thin films","authors":"Rajnarayan De, C. Kar, Kiran Baraik, B. R. Kumar, S. Pradhan","doi":"10.1063/5.0314171","DOIUrl":"https://doi.org/10.1063/5.0314171","url":null,"abstract":"The requirement of substantially higher growth temperature and post-deposition annealing for epitaxial growth of vanadium oxide (VO2) films has always remained a bottleneck for their practical applicability in various thermochromic smart devices. Here, we report epitaxial growth of vanadium oxide (VO2) thin films on sapphire substrates using the reactive gas pulsing technique (RGPT) in conjunction with intense plasma activation facilitated by asymmetric bipolar pulse DC (ABPDC) sputtering. The deposition methodology followed in this work utilizes growth temperature as low as 275 °C as opposed to the substantially higher temperatures (&gt;500 °C) reported in previous works. The process also avoids any post-processing of the films including annealing. The films deposited in RGPT mode show good environmental stability over a long time range using a simple deposition methodology without placing any top barrier layers to stop ageing. Investigation of the semiconductor-to-metal transition (SMT) behavior reveals a very sharp reversible first-order phase transition with sharpness ∼2 °C (very close to bulk single crystals) and switching ratio of ∼1 × 104 achieved with the RGPT mode. The epitaxial relationship of [010]VO2 ǁ [0001]Al2O3 (out-of-plane) and [001]VO2 ǁ [11-20]Al2O3 (in-plane) is established through the measurement of in-plane and out-of-plane microstructural characterization. Overall, this work presents a reliable method for the low temperature growth of epitaxial VO2 thin films with good environmental stability and excellent semiconductor–metal switching performance.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"32 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146160561","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}
Fengjun Zhuo, Zhenyu Dai, Kai Chang, Hongxin Yang, Zhenxiang Cheng
Twisted van der Waals (vdW) materials have emerged as a promising platform for exploring exotic quantum phenomena and engineering novel material properties in two dimensions, potentially revolutionizing developments in spintronics. This review provides an overview of recent progress on emerging moiré spintronics in twisted vdW materials, with a particular focus on two-dimensional magnetic materials. Following a brief introduction to the general features of twisted vdW materials, we discuss recent theoretical and experimental studies on stacking-dependent interlayer magnetism, non-collinear spin textures, moiré magnetic exchange interactions, moiré skyrmions, and moiré magnons. We further highlight the potential of machine learning to accelerate the discovery and design of multifunctional materials for moiré spintronics. Finally, we conclude by addressing the most pressing challenges and potential opportunities in this rapidly expanding field.
{"title":"Moiré spintronics: Emergent phenomena, material realization and machine learning accelerating discovery","authors":"Fengjun Zhuo, Zhenyu Dai, Kai Chang, Hongxin Yang, Zhenxiang Cheng","doi":"10.1063/5.0300788","DOIUrl":"https://doi.org/10.1063/5.0300788","url":null,"abstract":"Twisted van der Waals (vdW) materials have emerged as a promising platform for exploring exotic quantum phenomena and engineering novel material properties in two dimensions, potentially revolutionizing developments in spintronics. This review provides an overview of recent progress on emerging moiré spintronics in twisted vdW materials, with a particular focus on two-dimensional magnetic materials. Following a brief introduction to the general features of twisted vdW materials, we discuss recent theoretical and experimental studies on stacking-dependent interlayer magnetism, non-collinear spin textures, moiré magnetic exchange interactions, moiré skyrmions, and moiré magnons. We further highlight the potential of machine learning to accelerate the discovery and design of multifunctional materials for moiré spintronics. Finally, we conclude by addressing the most pressing challenges and potential opportunities in this rapidly expanding field.","PeriodicalId":8200,"journal":{"name":"Applied physics reviews","volume":"82 1","pages":""},"PeriodicalIF":15.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146161030","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}
Pub Date : 2026-02-10DOI: 10.1088/1475-7516/2026/02/027
Serena Gambino, Roberto Giambò and Orlando Luongo
We investigate relativistic Bondi accretion in the Simpson-Visser spacetime, which, via a single parameter ℓ, interpolates between the Schwarzschild, regular black hole, extremal and wormhole regimes. First, we analyse the neutral Simpson-Visser geometry, recovering Schwarzschild at ℓ=0, and then its charged extension of the Reissner-Nordström metric. In both these cases, we derive the conservation equations and analyse two representative fluid models: a barotropic perfect fluid and a constituent with an exponential density profile. By varying the parameters across regimes, we locate critical (sonic) points and integrate velocity, density, and pressure profiles. Although near-horizon inflow velocities are similar across the different solutions, we find that the critical radius, as well as the resulting accretion rates and luminosities, change significantly depending on the value of the parameter and the type of fluid. Remarkably, the barotropic and exponential cases exhibit different trends in the outer regions. Moreover, by extending the analysis to the charged SV spacetime, we find that the presence of a central charge Q produces additional, albeit modest, shifts in the sonic radius which, in combination with those induced by the regularisation parameter ℓ, could provide a double observational marker. In particular, while ℓ acts predominantly on the position of the critical point, in the barotropic fluid case, the electromagnetic contribution of Q slightly dampens the inflow velocity near the horizon.
{"title":"Bondi accretion disc luminosity around neutral and charged Simpson-Visser spacetimes","authors":"Serena Gambino, Roberto Giambò and Orlando Luongo","doi":"10.1088/1475-7516/2026/02/027","DOIUrl":"https://doi.org/10.1088/1475-7516/2026/02/027","url":null,"abstract":"We investigate relativistic Bondi accretion in the Simpson-Visser spacetime, which, via a single parameter ℓ, interpolates between the Schwarzschild, regular black hole, extremal and wormhole regimes. First, we analyse the neutral Simpson-Visser geometry, recovering Schwarzschild at ℓ=0, and then its charged extension of the Reissner-Nordström metric. In both these cases, we derive the conservation equations and analyse two representative fluid models: a barotropic perfect fluid and a constituent with an exponential density profile. By varying the parameters across regimes, we locate critical (sonic) points and integrate velocity, density, and pressure profiles. Although near-horizon inflow velocities are similar across the different solutions, we find that the critical radius, as well as the resulting accretion rates and luminosities, change significantly depending on the value of the parameter and the type of fluid. Remarkably, the barotropic and exponential cases exhibit different trends in the outer regions. Moreover, by extending the analysis to the charged SV spacetime, we find that the presence of a central charge Q produces additional, albeit modest, shifts in the sonic radius which, in combination with those induced by the regularisation parameter ℓ, could provide a double observational marker. In particular, while ℓ acts predominantly on the position of the critical point, in the barotropic fluid case, the electromagnetic contribution of Q slightly dampens the inflow velocity near the horizon.","PeriodicalId":15445,"journal":{"name":"Journal of Cosmology and Astroparticle Physics","volume":"35 1","pages":""},"PeriodicalIF":6.4,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146056","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}
Pub Date : 2026-02-10DOI: 10.1088/1361-6382/ae3b91
Anthony W Yu, Molly E Fahey, Kenji Numata, Yvonne Kandem Manewa, Ali Feizi, Frankie Micalizzi, Hua Jiao, Joseph Hart, Xiaozhen Xu, Stewart Wu, Kylan Jersey, Will Drobnick, Pat Burns, Jennifer Lee and Scott Merritt
NASA Goddard Space Flight Center (GSFC) is developing a laser system (LS) for the Laser Interferometer Space Antenna (LISA) mission, led by the European Space Agency with a launch date of 2035. The LS under development at NASA GSFC consists of a laser head, a frequency reference system, and power monitor detector assemblies. The LS development, which began in late 2016, follows the established NASA process in demonstrating the performance requirements through the development of various models to advance the technology readiness level (TRL) (www.nasa.gov/directorates/somd/space-communications-navigation-program/technology-readiness-levels/). The effort began with a successful demonstration of a laboratory breadboard (TRL 4) and has achieved a status of TRL-6 (flight-qualified) through rigorous testing and performance verification for space applications. In this paper, we provide an overview of the development and roadmap for advancing the LISA LS toward spaceflight by the NASA GSFC. Optomechanical and electronic details of each component and subsystems are presented in this paper, as well as test results and technical challenges that have been or are being overcome. As the project progresses, more detailed results will be reported in future publications including representative scientific data in support of the LISA launch, which is planned for 2035.
{"title":"Overview of the NASA LISA laser system development","authors":"Anthony W Yu, Molly E Fahey, Kenji Numata, Yvonne Kandem Manewa, Ali Feizi, Frankie Micalizzi, Hua Jiao, Joseph Hart, Xiaozhen Xu, Stewart Wu, Kylan Jersey, Will Drobnick, Pat Burns, Jennifer Lee and Scott Merritt","doi":"10.1088/1361-6382/ae3b91","DOIUrl":"https://doi.org/10.1088/1361-6382/ae3b91","url":null,"abstract":"NASA Goddard Space Flight Center (GSFC) is developing a laser system (LS) for the Laser Interferometer Space Antenna (LISA) mission, led by the European Space Agency with a launch date of 2035. The LS under development at NASA GSFC consists of a laser head, a frequency reference system, and power monitor detector assemblies. The LS development, which began in late 2016, follows the established NASA process in demonstrating the performance requirements through the development of various models to advance the technology readiness level (TRL) (www.nasa.gov/directorates/somd/space-communications-navigation-program/technology-readiness-levels/). The effort began with a successful demonstration of a laboratory breadboard (TRL 4) and has achieved a status of TRL-6 (flight-qualified) through rigorous testing and performance verification for space applications. In this paper, we provide an overview of the development and roadmap for advancing the LISA LS toward spaceflight by the NASA GSFC. Optomechanical and electronic details of each component and subsystems are presented in this paper, as well as test results and technical challenges that have been or are being overcome. As the project progresses, more detailed results will be reported in future publications including representative scientific data in support of the LISA launch, which is planned for 2035.","PeriodicalId":10282,"journal":{"name":"Classical and Quantum Gravity","volume":"284 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146146189","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}
Shenglin Wang, Yueying Niu, Wanlin Liu, Kehan Jiang, Kun Zhou, Hongyu Chai, Dan Lu, Xiaoguang Yang, Tao Yang
Silicon photonic integrated circuits (PICs) have emerged as cutting‐edge platforms for optical communication, interconnection, photonic computing, and sensing, delivering exceptional data throughput and energy‐efficient operation. A holy grail is the realization of light sources and photonic components monolithically integrated on a single silicon wafer. However, such integration faces formidable challenges in material engineering and integration techniques, especially for on‐chip light sources. Here, we propose a strategy for developing large‐scale monolithically‐integrated high‐speed interconnect chips via direct epitaxy of quantum dot (QD) materials on CMOS‐compatible (001) silicon substrate. On the basis of an eight‐layer QD epitaxial structure, we simultaneously fabricate direct modulation lasers and waveguide photodetectors (PDs) for emission and reception. Bandwidth measurements for the single QD lasers and PDs reveal 3 dB bandwidths of 4.5 GHz and 2.02 GHz, respectively. Non‐return‐to‐zero (NRZ) signal measurements show that the laser can achieve a maximum direct modulation rate of 12.5 Gbit/s, whereas the PD has a data reception capability of 5 Gbit/s. Moreover, a state‐of‐the‐art link rate of 1.01 GHz for on‐chip optical interconnection between the integrated lasers and PDs is demonstrated through a free‐space optical coupling structure. This work demonstrates a novel method to realize large‐scale monolithically‐integrated chips, which enables future versatile applications.
{"title":"Large‐Scale Monolithically‐Integrated High‐Speed Interconnect Chips via Direct Growth of InAs/GaAs Quantum Dot Lasers and Photodetectors on Si(001)","authors":"Shenglin Wang, Yueying Niu, Wanlin Liu, Kehan Jiang, Kun Zhou, Hongyu Chai, Dan Lu, Xiaoguang Yang, Tao Yang","doi":"10.1002/lpor.202503131","DOIUrl":"https://doi.org/10.1002/lpor.202503131","url":null,"abstract":"Silicon photonic integrated circuits (PICs) have emerged as cutting‐edge platforms for optical communication, interconnection, photonic computing, and sensing, delivering exceptional data throughput and energy‐efficient operation. A holy grail is the realization of light sources and photonic components monolithically integrated on a single silicon wafer. However, such integration faces formidable challenges in material engineering and integration techniques, especially for on‐chip light sources. Here, we propose a strategy for developing large‐scale monolithically‐integrated high‐speed interconnect chips via direct epitaxy of quantum dot (QD) materials on CMOS‐compatible (001) silicon substrate. On the basis of an eight‐layer QD epitaxial structure, we simultaneously fabricate direct modulation lasers and waveguide photodetectors (PDs) for emission and reception. Bandwidth measurements for the single QD lasers and PDs reveal 3 dB bandwidths of 4.5 GHz and 2.02 GHz, respectively. Non‐return‐to‐zero (NRZ) signal measurements show that the laser can achieve a maximum direct modulation rate of 12.5 Gbit/s, whereas the PD has a data reception capability of 5 Gbit/s. Moreover, a state‐of‐the‐art link rate of 1.01 GHz for on‐chip optical interconnection between the integrated lasers and PDs is demonstrated through a free‐space optical coupling structure. This work demonstrates a novel method to realize large‐scale monolithically‐integrated chips, which enables future versatile applications.","PeriodicalId":204,"journal":{"name":"Laser & Photonics Reviews","volume":"9 1","pages":""},"PeriodicalIF":11.0,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153397","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}
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