Science China Physics, Mechanics & Astronomy最新文献

{"title":"Five-user quantum virtual local area network with an AlGaAs entangled photon source","authors":"Cheng Qian,&nbsp;Hongkai Tian,&nbsp;Xu Jing,&nbsp;Yichen Liu,&nbsp;Zhe Chen,&nbsp;Huiran Luo,&nbsp;Yuan Du,&nbsp;Xiaodong Zheng,&nbsp;Tangsheng Chen,&nbsp;Yuechan Kong,&nbsp;Hua-Lei Yin,&nbsp;Dong Jiang,&nbsp;Bin Niu,&nbsp;Liangliang Lu","doi":"10.1007/s11433-024-2545-5","DOIUrl":"10.1007/s11433-024-2545-5","url":null,"abstract":"<div><p>The promotion of quantum network applications demands the scalable connection of quantum resources. It is preferable to set up multiple logical networks coexisting on a single physical network infrastructure to accommodate a larger number of users. Here we present a quantum virtual network architecture that offers this level of scalability, without being constrained to a fixed physical-layer network relying solely on passive multiplexing components. The architecture can be understood as arising from the superposition of a fully connected entanglement distribution network and port-based virtual local area network, which group multiusers by access ports. In terms of hardware, we leverage a semiconductor chip with a high figure-of-merit modal overlap to directly generate high-quality polarization entanglement, and a streamlined polarization analysis module, which requires only one single-photon detector for each end user. We experimentally perform the BBM92 QKD protocol on the five-user quantum virtual network and demonstrate voice and image encryption on a campus area network. Our results may provide insights into the realization of large-scale quantum networks with integrated and cost-efficient photonic architecture.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 3","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859681","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":"Advancing gravitational theory through the tetrahedral constellation gravitational wave observatory","authors":"Yun-Yong Wang,&nbsp;Zhou-Jian Cao","doi":"10.1007/s11433-024-2563-4","DOIUrl":"10.1007/s11433-024-2563-4","url":null,"abstract":"","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844910","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":"Spin-selective and frequency-shift meta-holography based on reconfigurable origami chiral metasurface","authors":"Zhibiao Zhu,&nbsp;Lixin Jiang,&nbsp;Zhe Qin,&nbsp;Yongfeng Li,&nbsp;Jiafu Wang,&nbsp;Yuxiang Jia,&nbsp;Lin Zheng,&nbsp;Shaobo Qu","doi":"10.1007/s11433-024-2534-7","DOIUrl":"10.1007/s11433-024-2534-7","url":null,"abstract":"<div><p>Origami-based reconfigurable metasurfaces have emerged as a versatile paradigm for dynamically manipulating electromagnetic (EM) waves due to their advantages, such as low manufacturing cost, lightweight, and structural deformability. Three-dimensional (3D) deformation can intensify asymmetry among structures, making origami metasurfaces particularly suitable for realizing reconfigurable chiral responses. However, previous studies have primarily focused on modulating spectral properties, such as chiral switching and resonant frequency shifting. There remains ample room for further exploration in complex wavefront manipulation and holographic imaging applications. This paper proposes a simple and efficient deformation method for origami metasurfaces that transforms a spin-insensitive planar metasurface into a 3D metasurface by folding. The breaking of mirror symmetry induces a pronounced chiral response. The binary amplitude is modulated within each pixel. When folded at angles of +<i>θ</i> and −<i>θ</i>, the designed origami metasurface generates distinct images under left-handed circularly polarized (LCP) wave incidence. Meanwhile, holographic encryption is achieved under right-handed circularly polarized (RCP) wave incidence. Furthermore, by leveraging origami’s reconfigurability, the holographic imaging’s operating frequency can be shifted. The experimental results agree well with the numerical calculations and full-wave simulations, demonstrating the broad application potential of this method in areas such as multi-channel imaging, information encryption technologies, and stealth.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845071","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":"Deciphering the α relaxation and the anelastic-to-plastic transition in the deep glassy state","authors":"Qi Hao,&nbsp;Guanghui Xing,&nbsp;Eloi Pineda,&nbsp;Claudio Fusco,&nbsp;Laurent Chazeau,&nbsp;Jean-Marc Pelletier,&nbsp;Yunjiang Wang,&nbsp;Yong Yang,&nbsp;Jichao Qiao","doi":"10.1007/s11433-024-2543-2","DOIUrl":"10.1007/s11433-024-2543-2","url":null,"abstract":"<div><p>In contrast to their conventional crystalline counterparts, amorphous solids exhibit diverse dynamic relaxation mechanisms under external stimuli. The challenge to understanding their behavior lies in unifying microscopic dynamics, relaxation, and macroscopic deformation. This study establishes a potential link by quantifying the characteristic time of the anelastic-to-plastic transition through dynamic mechanical relaxation and stress relaxation tests across a wide temperature range in both the supercooled liquid and the glassy state. It is found that the stress relaxation time in the glassy solids follows an Arrhenius relationship, aligning with the main α relaxation time, and unveils a finding: α relaxation continues to govern deformation even below the glass transition, challenging previous assumptions of the role of secondary β relaxation. A hierarchically constrained atomic dynamics model rationalizes the temperature dependence of α relaxation and the transition from β to α relaxation, also providing evidence that the stretched exponent in the Kohlrausch-Williams-Watts equation can serve as an order parameter. This work highlights the role of α relaxation in the glassy state and contributes to elucidating the potential correlation between relaxation and deformation in amorphous materials.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 3","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845069","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":"Spin freezing induced giant exchange bias in a doped Hund’s metal","authors":"Shunjiao Li,&nbsp;Dan Zhao,&nbsp;Jian Li,&nbsp;Baolei Kang,&nbsp;Min Shan,&nbsp;Yanbing Zhou,&nbsp;Xuyang Li,&nbsp;Tao Wu,&nbsp;Xianhui Chen","doi":"10.1007/s11433-024-2531-7","DOIUrl":"10.1007/s11433-024-2531-7","url":null,"abstract":"<div><p>Exchange bias (EB) is a fundamental phenomenon in widespread information technologies. However, a comprehensive understanding of its microscopic origin remains a great challenge. One key issue in the debate is the role of frustration and disorder in the EB mechanism, which motivates the exploration of the EB effect in spin glass (SG) systems. Here, in the SG state of Cr-doped Hund’s metal CsFe₂As₂, we discover a giant EB effect with a maximum bias field of ∼2 T, which is almost two orders of magnitude larger than that of traditional alloy SGs. Our results indicate that the giant EB effect should originate from the exchange interactions at the natural boundaries between the tunable ferromagnetic-like (FM) regions around Cr dopants and the SG matrix, via which the FM spins are strongly pinned by the frozen spins in the SG matrix. In addition, the temperature-dependent and cooling-field-dependent EB behaviors could be interpreted well by the SG model with frustrated FM/SG boundaries, which provides an intuitive and explicit understanding of the impact of glassy parameters on the EB effect. All these results suggest that the correlated metals are promising directions for exploring the EB effect in the SG state.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845072","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":"Pressure induced superconducting dome in LaNiGa2","authors":"Yanan Zhang,&nbsp;Dajun Su,&nbsp;Zhaoyang Shan,&nbsp;Yunshu Shi,&nbsp;Rui Li,&nbsp;Jinyu Wu,&nbsp;Zihan Yang,&nbsp;Kaixin Ye,&nbsp;Fei Zhang,&nbsp;Yanchun Li,&nbsp;Xiaodong Li,&nbsp;Chao Cao,&nbsp;Valentin Taufour,&nbsp;Lin Jiao,&nbsp;Michael Smidman,&nbsp;Huiqiu Yuan","doi":"10.1007/s11433-024-2536-6","DOIUrl":"10.1007/s11433-024-2536-6","url":null,"abstract":"<div><p>LaNiGa₂ is a time-reversal symmetry breaking superconductor with symmetry protected band crossings, making it an ideal platform for investigating the interplay between unconventional superconductivity and electronic structure topology. Here we present a transport study of LaNiGa₂ under pressure. The application of pressure to LaNiGa₂ induces a significant enhancement of the superconducting transition temperature <i>T</i>_c at a pressure of 7 GPa. In contrast, powder X-ray diffraction (XRD) results show no evidence of structural phase transitions up to 26.3 GPa. Moreover, the ratio of band diffusivity shows a sudden increase at around 7 GPa, suggesting possible pressure-induced changes in the electronic structure that are closely linked to the evolution of superconductivity.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810970","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":"Tetrahedron constellation of gravitational wave observatory","authors":"Hong-Bo Jin,&nbsp;Cong-Feng Qiao","doi":"10.1007/s11433-024-2519-6","DOIUrl":"10.1007/s11433-024-2519-6","url":null,"abstract":"<div><p>For the first time, we have introduced the tetrahedron constellation of gravitational wave observatory (TEGO) composed of four identical spacecrafts (S/Cs). The laser telescopes and their pointing structures are mounted on the S/C platform and are evenly distributed at three locations 120 degrees apart. These structures form automatically a stable mass center for the platform. The time delay interferometry (TDI) is used to suppress the frequency noise of gravitational wave (GW) detector. The unequal-arm Michelson TDI configuration and the Sagnac TDI configuration are equally effective at eliminating the laser frequency noise based on the TEGO configuration. Furthermore, compared with the configurations of LISA, Taiji, and TianQin, the TEGO has more combinations of optical paths in its TDI system sensitive to GW signals. The six arms of TEGO are simultaneously sensitive to the six polarization modes of GWs. The sensitivity implies that GW modes beyond the predictions of general relativity (GR) can be detected directly. For instance, a scalar longitudinal mode of GWs, which is not predicted by GR, has been identified as a dominant polarization component. This mode is found to be evident in the response amplitudes of the TEGO arms, such as between S/C1 and S/C4, and S/C3 and S/C4, at certain orbital positions.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821372","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":"Optimizing frequency allocation for superconducting quantum processors with frequency-tunable qubits","authors":"Bi-Ying Wang,&nbsp;Wuxin Liu,&nbsp;Xiangyu Chen,&nbsp;Shu Xu,&nbsp;Jiangyu Cui,&nbsp;Man-Hong Yung","doi":"10.1007/s11433-024-2527-3","DOIUrl":"10.1007/s11433-024-2527-3","url":null,"abstract":"<div><p>As superconducting quantum processors scale, a key challenge is maintaining high coherence times and fidelity control over numerous qubits. We propose an automatic frequency allocation method for frequency-tunable qubits that equally considers coherence-limited fidelity and crosstalk-induced control errors during the allocation process. By employing a weighted average of the objective functions for coherence time and crosstalk, we numerically calculate gate fidelity to establish an open-loop optimization for determining suitable weight factors. This results in an efficient objective function for frequency optimization. We apply our method to frequency-tunable transmon qubits with tunable couplers, both theoretically and experimentally. The numerical results demonstrate significant advantages, including substantial reductions in gate errors and faster operation times, especially at higher qubit counts. Experimentally, our approach successfully achieves approximately 99.9% single-qubit fidelity on a nine-qubit chip.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 2","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821373","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":"Is the Gum Nebula an important interstellar scattering disk of background pulsars?","authors":"Rui Wang,&nbsp;Zhen Yan,&nbsp;Zhiqiang Shen,&nbsp;KeJia Lee,&nbsp;Yajun Wu,&nbsp;Rongbing Zhao,&nbsp;Zhipeng Huang,&nbsp;Xiaowei Wang,&nbsp;Jie Liu","doi":"10.1007/s11433-024-2511-6","DOIUrl":"10.1007/s11433-024-2511-6","url":null,"abstract":"<div><p>The Gum Nebula is a faint supernova remnant extending about 40° across the southern sky, potentially affecting tens of background pulsars. Though the view that the Gum Nebula acts as a potential scattering screen for background pulsars has been recurrently mentioned over the past five decades, it has not been directly confirmed. We chose the strong background pulsar PSR B0740-28 as a probe and monitored its diffractive interstellar scintillation (DISS) at 2.25 &amp; 8.60 GHz simultaneously for about two years using the Shanghai Tian Ma Radio Telescope (TMRT). DISS was detected at both frequencies and quantified by two-dimensional autocorrelation analysis. We calculated their scattering spectral index α and found that 9/21 of the observations followed the theoretical predictions, while 4/21 of them clearly showed <i>α</i> &lt; 4. This finding provides strong support for anomalous scattering along the pulsar line of sight, due to the large frequency lever arm and the simultaneous features of our dual-frequency observations. In comparison to the 2.25 GHz observations, scintillation arcs were observed in 10/21 of the secondary spectrum plots for 8.60 GHz observations. Consequently, the highest frequency record for pulsar scintillation arc detection was updated to 8.60 GHz. Our fitting results were the most direct evidence for the view that the Gum Nebula acts as the scattering screen for background pulsars, because both the distance (245<span>\u0000 ⁺⁶⁹₋₇₂\u0000 \u0000 </span> pc) and transverse speed (22.4<span>\u0000 ^4.1_−4.2\u0000 \u0000 </span> km s⁻¹) of the scintillation screen are comparable with related parameters of the Gum Nebula. Our findings indicated that anisotropic scattering provides a superior explanation for the annual modulation of scintillation arcs than isotropic scattering. Additionally, the orientation of its long axis was also fitted.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 3","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821374","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":"The GECAM ground search system for gamma-ray transients","authors":"Ce Cai,&nbsp;Yan-Qiu Zhang,&nbsp;Shao-Lin Xiong,&nbsp;Ping Wang,&nbsp;Jian-Hui Li,&nbsp;Xiao-Bo Li,&nbsp;Cheng-Kui Li,&nbsp;Yue Huang,&nbsp;Shi-Jie Zheng,&nbsp;Li-Ming Song,&nbsp;Shuo Xiao,&nbsp;Qi-Bin Yi,&nbsp;Yi Zhao,&nbsp;Sheng-Lun Xie,&nbsp;Rui Qiao,&nbsp;Yan-Qi Du,&nbsp;Zhi-Wei Guo,&nbsp;Wang-Chen Xue,&nbsp;Chao Zheng,&nbsp;Jia-Cong Liu,&nbsp;Chen-Wei Wang,&nbsp;Wen-Jun Tan,&nbsp;Yue Wang,&nbsp;Jin-Peng Zhang,&nbsp;Chao-Yang Li,&nbsp;Guo-Ying Zhao,&nbsp;Xiao-Yun Zhao,&nbsp;Xiao-Lu Zhang,&nbsp;Zhen Zhang,&nbsp;Wen-Xi Peng,&nbsp;Xiang Ma,&nbsp;Jing-Yan Shi,&nbsp;Dong-Ya Guo,&nbsp;Jin Wang,&nbsp;Xin-Qiao Li,&nbsp;Xiang-Yang Wen,&nbsp;Zheng-Hua An,&nbsp;Fan Zhang","doi":"10.1007/s11433-024-2544-3","DOIUrl":"10.1007/s11433-024-2544-3","url":null,"abstract":"<div><p>In the era of time-domain, multi-messenger astronomy, the detection of transient events on the high-energy electromagnetic sky has become more important than ever. The gravitational wave high-energy electromagnetic counterpart all-sky monitor (GECAM) is a dedicated mission to monitor gamma-ray transients, launched in December, 2020. A real-time on-board trigger and location software, using the traditional signal-to-noise ratio (SNR) method for blind search, is constrained to relatively bright signals due to the limitations in on-board computing resources and the need for real-time search. In this work, we developed a ground-based pipeline for GECAM to search for various transients, especially for weak bursts missed by on-board software. This pipeline includes both automatic and manual mode, offering options for blind search and targeted search. The targeted search is specifically designed to search for interesting weak bursts, such as gravitational wave-associated gamma-ray bursts (GRBs). From the ground search of the data in the first year, GECAM has been triggered by 54 GRBs and other transients, including soft gamma-ray repeaters, X-ray binaries, solar flares, terrestrial gamma-ray flashes. We report the properties of each type of triggers, such as trigger time and light curves. With this search pipeline and assuming a soft Band spectrum, the GRB detection sensitivity of GECAM is increased to about 1.1 × 10⁻⁸ erg cm⁻² s⁻¹ (10–1000 keV, burst duration of 20 s). These results demonstrate that the GECAM ground search system (both blind search and targeted search) is a versatile pipeline to recover true astrophysical signals which were too weak to be found in the on-board search.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":"68 3","pages":""},"PeriodicalIF":6.4,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142790406","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}