Pub Date : 2024-02-12DOI: 10.1007/s11467-023-1376-1
Junrong Zhang, Cheng Chen, Yanming Wang, Yang Lu, Honghong Li, Xingang Hou, Yaning Liang, Long Fang, Du Xiang, Kai Zhang, Junyong Wang
The low-dimensional light source shows promise in photonic integrated circuits. Stable layered van der Waals material that exhibits luminescence in the near-infrared optical communication waveband is an essential component in on-chip light sources. Herein, the tunable near-infrared photoluminescence (PL) of the air-stable layered titanium trisulfide (TiS3) is reported. Compared with iodine particles as a transport agent, TiS3 grown by chemical vapor transport using sulfur powder as a transport agent has fewer sulfur vacancies, which increases the luminescence intensity by an order of magnitude. The PL emission wavelength can be regulated in the near-infrared regime by thickness control. In addition, we observed an interesting anisotropic strain response of PL in layered TiS3 nanoribbon: a blue shift of PL was achieved when the uniaxial tensile strain was applied along the b-axis, while a negligible shift was observed when the strain was applied along the a-axis. Our work reveals the tunable near-infrared luminescent properties of TiS3 nanoribbons, suggesting their potential applications as near-infrared light sources in photonic integrated circuits.
低维光源在光子集成电路中大有可为。能在近红外光通信波段发光的稳定层状范德华材料是片上光源的重要组成部分。本文报告了空气稳定的层状三硫化钛(TiS3)的可调近红外光致发光(PL)。与作为传输剂的碘粒子相比,以硫磺粉为传输剂通过化学气相传输生长的 TiS3 具有更少的硫空位,从而将发光强度提高了一个数量级。通过厚度控制,可在近红外范围内调节 PL 发射波长。此外,我们还在层状 TiS3 纳米带中观察到了有趣的各向异性应变响应:当沿 b 轴施加单轴拉伸应变时,PL 会发生蓝移;而沿 a 轴施加应变时,PL 的蓝移可以忽略不计。我们的研究揭示了 TiS3 纳米带的可调近红外发光特性,这表明它们有望在光子集成电路中用作近红外光源。
{"title":"Tunable near-infrared light emission from layered TiS3 nanoribbons","authors":"Junrong Zhang, Cheng Chen, Yanming Wang, Yang Lu, Honghong Li, Xingang Hou, Yaning Liang, Long Fang, Du Xiang, Kai Zhang, Junyong Wang","doi":"10.1007/s11467-023-1376-1","DOIUrl":"https://doi.org/10.1007/s11467-023-1376-1","url":null,"abstract":"<p>The low-dimensional light source shows promise in photonic integrated circuits. Stable layered van der Waals material that exhibits luminescence in the near-infrared optical communication waveband is an essential component in on-chip light sources. Herein, the tunable near-infrared photoluminescence (PL) of the air-stable layered titanium trisulfide (TiS<sub>3</sub>) is reported. Compared with iodine particles as a transport agent, TiS<sub>3</sub> grown by chemical vapor transport using sulfur powder as a transport agent has fewer sulfur vacancies, which increases the luminescence intensity by an order of magnitude. The PL emission wavelength can be regulated in the near-infrared regime by thickness control. In addition, we observed an interesting anisotropic strain response of PL in layered TiS<sub>3</sub> nanoribbon: a blue shift of PL was achieved when the uniaxial tensile strain was applied along the <i>b</i>-axis, while a negligible shift was observed when the strain was applied along the <i>a</i>-axis. Our work reveals the tunable near-infrared luminescent properties of TiS<sub>3</sub> nanoribbons, suggesting their potential applications as near-infrared light sources in photonic integrated circuits.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769991","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}
By accurately measuring composition and energy spectrum of cosmic ray, the origin problem of so called “knee” region (energy >one PeV) can be solved. However, up to the present, the results of the spectrum in the knee region obtained by several previous experiments have shown obvious differences, so they cannot give effective evidence for judging the theoretical models on the origin of the knee. Recently, the Large High Altitude Air Shower Observatory (LHAASO) has reported several major breakthroughs and important results in astro-particle physics field. Relying on its advantages of wide-sky survey, high altitude location and large area detector arrays, the research content of LHAASO experiment mainly includes ultra high-energy gamma-ray astronomy, measurement of cosmic ray spectra in the knee region, searching for dark matter and new phenomena of particle physics at higher energy. The electron and thermal neutron detector (EN-Detector) is a new scintillator detector which applies thermal neutron detection technology to measure cosmic ray extensive air shower (EAS). This technology is an extension of LHAASO. The EN-Detector Array (ENDA) can highly efficiently measure thermal neutrons generated by secondary hadrons so called “skeleton” of EAS. In this paper, we perform the optimization of ENDA configuration, and obtain expectations on the ENDA results, including thermal neutron distribution, trigger efficiency and capability of cosmic ray composition separation. The obtained real data results are consistent with those by the Monte Carlo simulation.
{"title":"Research on the knee region of cosmic ray by using a novel type of electron–neutron detector array","authors":"Bing-Bing Li, Xin-Hua Ma, Shu-Wang Cui, Hao-Kun Chen, Tian-Lu Chen, Danzengluobu, Wei Gao, Hai-Bing Hu, Denis Kuleshov, Kirill Kurinov, Hu Liu, Mao-Yuan Liu, Ye Liu, Da-Yu Peng, Yao-Hui Qi, Oleg Shchegolev, Yuri Stenkin, Li-Qiao Yin, Heng-Yu Zhang, Liang-Wei Zhang","doi":"10.1007/s11467-023-1383-2","DOIUrl":"https://doi.org/10.1007/s11467-023-1383-2","url":null,"abstract":"<p>By accurately measuring composition and energy spectrum of cosmic ray, the origin problem of so called “knee” region (energy >one PeV) can be solved. However, up to the present, the results of the spectrum in the knee region obtained by several previous experiments have shown obvious differences, so they cannot give effective evidence for judging the theoretical models on the origin of the knee. Recently, the Large High Altitude Air Shower Observatory (LHAASO) has reported several major breakthroughs and important results in astro-particle physics field. Relying on its advantages of wide-sky survey, high altitude location and large area detector arrays, the research content of LHAASO experiment mainly includes ultra high-energy gamma-ray astronomy, measurement of cosmic ray spectra in the knee region, searching for dark matter and new phenomena of particle physics at higher energy. The electron and thermal neutron detector (EN-Detector) is a new scintillator detector which applies thermal neutron detection technology to measure cosmic ray extensive air shower (EAS). This technology is an extension of LHAASO. The EN-Detector Array (ENDA) can highly efficiently measure thermal neutrons generated by secondary hadrons so called “skeleton” of EAS. In this paper, we perform the optimization of ENDA configuration, and obtain expectations on the ENDA results, including thermal neutron distribution, trigger efficiency and capability of cosmic ray composition separation. The obtained real data results are consistent with those by the Monte Carlo simulation.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769997","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 : 2024-02-07DOI: 10.1007/s11467-023-1382-3
Xu-Dan Xie, Zheng-Yuan Xue, Dan-Bo Zhang
Solving non-Hermitian quantum many-body systems on a quantum computer by minimizing the variational energy is challenging as the energy can be complex. Here, we propose a variational quantum algorithm for solving the non-Hermitian Hamiltonian by minimizing a type of energy variance, where zero variance can naturally determine the eigenvalues and the associated left and right eigenstates. Moreover, the energy is set as a parameter in the cost function and can be tuned to scan the whole spectrum efficiently by using a two-step optimization scheme. Through numerical simulations, we demonstrate the algorithm for preparing the left and right eigenstates, verifying the biorthogonal relations, as well as evaluating the observables. We also investigate the impact of quantum noise on our algorithm and show that its performance can be largely improved using error mitigation techniques. Therefore, our work suggests an avenue for solving non-Hermitian quantum many-body systems with variational quantum algorithms on near-term noisy quantum computers.
{"title":"Variational quantum algorithms for scanning the complex spectrum of non-Hermitian systems","authors":"Xu-Dan Xie, Zheng-Yuan Xue, Dan-Bo Zhang","doi":"10.1007/s11467-023-1382-3","DOIUrl":"https://doi.org/10.1007/s11467-023-1382-3","url":null,"abstract":"<p>Solving non-Hermitian quantum many-body systems on a quantum computer by minimizing the variational energy is challenging as the energy can be complex. Here, we propose a variational quantum algorithm for solving the non-Hermitian Hamiltonian by minimizing a type of energy variance, where zero variance can naturally determine the eigenvalues and the associated left and right eigenstates. Moreover, the energy is set as a parameter in the cost function and can be tuned to scan the whole spectrum efficiently by using a two-step optimization scheme. Through numerical simulations, we demonstrate the algorithm for preparing the left and right eigenstates, verifying the biorthogonal relations, as well as evaluating the observables. We also investigate the impact of quantum noise on our algorithm and show that its performance can be largely improved using error mitigation techniques. Therefore, our work suggests an avenue for solving non-Hermitian quantum many-body systems with variational quantum algorithms on near-term noisy quantum computers.</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769830","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 : 2024-02-07DOI: 10.1007/s11467-023-1380-5
Kaifan Zhang, Weiran Song, Zongyu Hou, Zhe Wang
Laser-induced breakdown spectroscopy (LIBS) is regarded as the future superstar for analytical chemistry and widely applied in various fields. Improving the quality of LIBS signal is fundamental to achieving accurate quantification and large-scale commercialization of LIBS. To propose control methods that improve LIBS signal quality, it is essential to have a comprehensive understanding of the influence of key parameters, such as ambient gas pressure, temperature, and sample temperature on LIBS signals. To date, extensive research has been carried out. However, different researchers often yield significantly different experimental results for LIBS, preventing the formation of consistent conclusions. This greatly prevents the understanding of influencing laws of key parameters and the improvement of LIBS quantitative performance. Taking ambient gas pressure as an example, this paper compares the effects of ambient gas pressure under different optimization conditions, reveals the influence of spatiotemporal window caused by inherent characteristics of LIBS signal sources, i.e., intense temporal changes and spatial non-uniformity of laser-induced plasmas, on the impact patterns of key parameters. From the perspective of plasma spatiotemporal evolution, the paper elucidates the influence patterns of ambient gas pressure on LIBS signals, clarifying seemingly contradictory research results in the literature.
{"title":"Effect of ambient pressures on laser-induced breakdown spectroscopy signals","authors":"Kaifan Zhang, Weiran Song, Zongyu Hou, Zhe Wang","doi":"10.1007/s11467-023-1380-5","DOIUrl":"https://doi.org/10.1007/s11467-023-1380-5","url":null,"abstract":"<p>Laser-induced breakdown spectroscopy (LIBS) is regarded as the future superstar for analytical chemistry and widely applied in various fields. Improving the quality of LIBS signal is fundamental to achieving accurate quantification and large-scale commercialization of LIBS. To propose control methods that improve LIBS signal quality, it is essential to have a comprehensive understanding of the influence of key parameters, such as ambient gas pressure, temperature, and sample temperature on LIBS signals. To date, extensive research has been carried out. However, different researchers often yield significantly different experimental results for LIBS, preventing the formation of consistent conclusions. This greatly prevents the understanding of influencing laws of key parameters and the improvement of LIBS quantitative performance. Taking ambient gas pressure as an example, this paper compares the effects of ambient gas pressure under different optimization conditions, reveals the influence of spatiotemporal window caused by inherent characteristics of LIBS signal sources, i.e., intense temporal changes and spatial non-uniformity of laser-induced plasmas, on the impact patterns of key parameters. From the perspective of plasma spatiotemporal evolution, the paper elucidates the influence patterns of ambient gas pressure on LIBS signals, clarifying seemingly contradictory research results in the literature.</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769923","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 : 2024-02-01DOI: 10.1007/s11467-023-1381-4
B. Li, D. Vretenar, T. Nikšić, J. Zhao, P. W. Zhao, J. Meng
The generalized time-dependent generator coordinate method (TD-GCM) is extended to include pairing correlations. The correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight functions. The particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional, while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation probabilities. With the inclusion of pairing correlations, various time-dependent phenomena in open-shell nuclei can be described more realistically. The model is applied to the description of saddle-to-scission dynamics of induced fission. The generalized TD-GCM charge yields and total kinetic energy distribution for the fission of 240Pu, are compared to those obtained using the standard time-dependent density functional theory (TD-DFT) approach, and with available data.
{"title":"Generalized time-dependent generator coordinate method for induced fission dynamics","authors":"B. Li, D. Vretenar, T. Nikšić, J. Zhao, P. W. Zhao, J. Meng","doi":"10.1007/s11467-023-1381-4","DOIUrl":"https://doi.org/10.1007/s11467-023-1381-4","url":null,"abstract":"<p>The generalized time-dependent generator coordinate method (TD-GCM) is extended to include pairing correlations. The correlated GCM nuclear wave function is expressed in terms of time-dependent generator states and weight functions. The particle–hole channel of the effective interaction is determined by a Hamiltonian derived from an energy density functional, while pairing is treated dynamically in the standard BCS approximation with time-dependent pairing tensor and single-particle occupation probabilities. With the inclusion of pairing correlations, various time-dependent phenomena in open-shell nuclei can be described more realistically. The model is applied to the description of saddle-to-scission dynamics of induced fission. The generalized TD-GCM charge yields and total kinetic energy distribution for the fission of <sup>240</sup>Pu, are compared to those obtained using the standard time-dependent density functional theory (TD-DFT) approach, and with available data.</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139664610","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 : 2024-01-27DOI: 10.1007/s11467-023-1374-3
Ran Ma, Qiuhong Tan, Peizhi Yang, Yingkai Liu, Qianjin Wang
Two-dimensional (2D) transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors. However, their relatively low responsivities, current on/off ratios and response speeds have hindered their widespread application. Herein, we fabricated a high-performance photodetector based on few-layer MoTe2 and CdS0.42Se0.58 flake heterojunctions. The photodetector exhibited a high responsivity of 7221 A/W, a large current on/off ratio of 1.73×104, a fast response speed of 90/120 µs, external quantum efficiency (EQE) reaching up to 1.52×106 % and detectivity (D*) reaching up to 1.67×1015 Jones. The excellent performance of the heterojunction photodetector was analyzed by a photocurrent mapping test and first-principle calculations. Notably, the visible light imaging function was successfully attained on the MoTe2/CdS0.42Se0.58 photodetectors, indicating that the device had practical imaging application prospects. Our findings provide a reference for the design of ultrahigh-performance MoTe2-based photodetectors.
{"title":"High performance photodetector based on few-layer MoTe2/CdS0.42Se0.58 flake heterojunction","authors":"Ran Ma, Qiuhong Tan, Peizhi Yang, Yingkai Liu, Qianjin Wang","doi":"10.1007/s11467-023-1374-3","DOIUrl":"https://doi.org/10.1007/s11467-023-1374-3","url":null,"abstract":"<p>Two-dimensional (2D) transition metal dichalcogenides have been extensively studied due to their fascinating physical properties for constructing high-performance photodetectors. However, their relatively low responsivities, current on/off ratios and response speeds have hindered their widespread application. Herein, we fabricated a high-performance photodetector based on few-layer MoTe<sub>2</sub> and CdS<sub>0.42</sub>Se<sub>0.58</sub> flake heterojunctions. The photodetector exhibited a high responsivity of 7221 A/W, a large current on/off ratio of 1.73×10<sup>4</sup>, a fast response speed of 90/120 µs, external quantum efficiency (EQE) reaching up to 1.52×10<sup>6</sup> % and detectivity (<i>D*</i>) reaching up to 1.67×10<sup>15</sup> Jones. The excellent performance of the heterojunction photodetector was analyzed by a photocurrent mapping test and first-principle calculations. Notably, the visible light imaging function was successfully attained on the MoTe<sub>2</sub>/CdS<sub>0.42</sub>Se<sub>0.58</sub> photodetectors, indicating that the device had practical imaging application prospects. Our findings provide a reference for the design of ultrahigh-performance MoTe<sub>2</sub>-based photodetectors.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139584409","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 : 2024-01-24DOI: 10.1007/s11467-023-1377-0
Zhexi He, Yifan Zhao, Yujing Du, Meng Zhao, Yuxuan Jiang, Ming Liu, Ziyao Zhou
Flexible electronics/spintronics attracts researchers’ attention for their application potential abroad in wearable devices, healthcare, and other areas. Those devices’ performance (speed, energy consumption) is highly dependent on manipulating information bits (spin-orientation in flexible spintronics). In this work, we established an organic photovoltaic (OPV)/ ZnO/Pt/Co/Pt heterostructure on flexible PET substrates with perpendicular magnetic anisotropy (PMA). Under sunlight illumination, the photo-electrons generated from the OPV layer transfer into the PMA heterostructure, then they reduce the PMA strength by enhancing the interfacial Rashba field accordingly. The coercive field (Hc) reduces from 800 Oe to 500 Oe at its maximum, and the magnetization can be switched up and down reversibly. The stability of sunlight control of magnetization reversal under various bending conditions is also tested for flexible spintronic applications. Lastly, the voltage output of sunlight-driven PMA is achieved in our prototype device, exhibiting an excellent angular dependence and opening a door towards solar-driven flexible spintronics with much lower energy consumption.
{"title":"Solar manipulations of perpendicular magnetic anisotropy for flexible spintronics","authors":"Zhexi He, Yifan Zhao, Yujing Du, Meng Zhao, Yuxuan Jiang, Ming Liu, Ziyao Zhou","doi":"10.1007/s11467-023-1377-0","DOIUrl":"https://doi.org/10.1007/s11467-023-1377-0","url":null,"abstract":"<p>Flexible electronics/spintronics attracts researchers’ attention for their application potential abroad in wearable devices, healthcare, and other areas. Those devices’ performance (speed, energy consumption) is highly dependent on manipulating information bits (spin-orientation in flexible spintronics). In this work, we established an organic photovoltaic (OPV)/ ZnO/Pt/Co/Pt heterostructure on flexible PET substrates with perpendicular magnetic anisotropy (PMA). Under sunlight illumination, the photo-electrons generated from the OPV layer transfer into the PMA heterostructure, then they reduce the PMA strength by enhancing the interfacial Rashba field accordingly. The coercive field (<i>H</i><sub>c</sub>) reduces from 800 Oe to 500 Oe at its maximum, and the magnetization can be switched up and down reversibly. The stability of sunlight control of magnetization reversal under various bending conditions is also tested for flexible spintronic applications. Lastly, the voltage output of sunlight-driven PMA is achieved in our prototype device, exhibiting an excellent angular dependence and opening a door towards solar-driven flexible spintronics with much lower energy consumption.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139558355","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}
Whether the complex game system composed of a large number of artificial intelligence (AI) agents empowered with reinforcement learning can produce extremely favorable collective behaviors just through the way of agent self-exploration is a matter of practical importance. In this paper, we address this question by combining the typical theoretical model of resource allocation system, the minority game model, with reinforcement learning. Each individual participating in the game is set to have a certain degree of intelligence based on reinforcement learning algorithm. In particular, we demonstrate that as AI agents gradually becomes familiar with the unknown environment and tries to provide optimal actions to maximize payoff, the whole system continues to approach the optimal state under certain parameter combinations, herding is effectively suppressed by an oscillating collective behavior which is a self-organizing pattern without any external interference. An interesting phenomenon is that a first-order phase transition is revealed based on some numerical results in our multi-agents system with reinforcement learning. In order to further understand the dynamic behavior of agent learning, we define and analyze the conversion path of belief mode, and find that the self-organizing condensation of belief modes appeared for the given trial and error rates in the AI system. Finally, we provide a detection method for period-two oscillation collective pattern emergence based on the Kullback–Leibler divergence and give the parameter position where the period-two appears.
{"title":"Self organizing optimization and phase transition in reinforcement learning minority game system","authors":"Si-Ping Zhang, Jia-Qi Dong, Hui-Yu Zhang, Yi-Xuan Lü, Jue Wang, Zi-Gang Huang","doi":"10.1007/s11467-023-1378-z","DOIUrl":"https://doi.org/10.1007/s11467-023-1378-z","url":null,"abstract":"<p>Whether the complex game system composed of a large number of artificial intelligence (AI) agents empowered with reinforcement learning can produce extremely favorable collective behaviors just through the way of agent self-exploration is a matter of practical importance. In this paper, we address this question by combining the typical theoretical model of resource allocation system, the minority game model, with reinforcement learning. Each individual participating in the game is set to have a certain degree of intelligence based on reinforcement learning algorithm. In particular, we demonstrate that as AI agents gradually becomes familiar with the unknown environment and tries to provide optimal actions to maximize payoff, the whole system continues to approach the optimal state under certain parameter combinations, herding is effectively suppressed by an oscillating collective behavior which is a self-organizing pattern without any external interference. An interesting phenomenon is that a first-order phase transition is revealed based on some numerical results in our multi-agents system with reinforcement learning. In order to further understand the dynamic behavior of agent learning, we define and analyze the conversion path of belief mode, and find that the self-organizing condensation of belief modes appeared for the given trial and error rates in the AI system. Finally, we provide a detection method for period-two oscillation collective pattern emergence based on the Kullback–Leibler divergence and give the parameter position where the period-two appears.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139558723","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 : 2024-01-24DOI: 10.1007/s11467-023-1375-2
V. A. Tomilin, L. V. Il’ichov
We present a novel feedback control method for quantum systems. Feedback does not affect the controlled system itself. Instead, it controls the unravelling of the quantum channel of interaction between the system and its environment. This interaction can be represented as a history of events. If their informational content is changed, their back-action on the system is also modified. Feedback action is trigged by the events, thus granting the system the degree of control over its own state. The efficiency of the proposed scheme is demonstrated on the example of two-mode atomic Bose-Einstein condensate, with one of its modes subject to phase-contrast imaging in a Mach–Zehnder interferometer. The histories of photocounts in the output channels of the interferometer are used for feedback. Its capabilities of state engineering are studied for different settings of the feedback loop and different numbers of events in the recorded histories.
{"title":"Unravelling-based (auto)control of back-action in atomic Bose–Einstein condensate","authors":"V. A. Tomilin, L. V. Il’ichov","doi":"10.1007/s11467-023-1375-2","DOIUrl":"https://doi.org/10.1007/s11467-023-1375-2","url":null,"abstract":"<p>We present a novel feedback control method for quantum systems. Feedback does not affect the controlled system itself. Instead, it controls the unravelling of the quantum channel of interaction between the system and its environment. This interaction can be represented as a history of events. If their informational content is changed, their back-action on the system is also modified. Feedback action is trigged by the events, thus granting the system the degree of control over its own state. The efficiency of the proposed scheme is demonstrated on the example of two-mode atomic Bose-Einstein condensate, with one of its modes subject to phase-contrast imaging in a Mach–Zehnder interferometer. The histories of photocounts in the output channels of the interferometer are used for feedback. Its capabilities of state engineering are studied for different settings of the feedback loop and different numbers of events in the recorded histories.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139558208","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 : 2024-01-24DOI: 10.1007/s11467-023-1379-y
P. M. Marychev, A. A. Shanenko, A. V. Vagov
Nonmagnetic impurity scattering is known to shift up the Ginzburg–Landau parameter κ of a superconductor. In this case, when the system is initially in type I, it can change its magnetic response, crossing the intertype domain with κ ∼ 1 between the two standard superconductivity types and arriving at type II. In the present work we demonstrate that the impact of disorder can be much more profound in the presence of the multiband structure of the charge carrier states. In particular, when the band diffusivities differ from each other, the intertype domain tends to expand significantly, including points with κ ≫ 1 that belong to deep type-II in conventional single-band superconductors. Our finding sheds light on the nontrivial disorder effect and significantly complements earlier results on the enlargement of the intertype domain in clean multiband superconductors.
众所周知,非磁性杂质散射会使超导体的金兹堡-朗道参数κ上移。在这种情况下,当系统最初处于 I 型时,它可以改变磁响应,跨越介于两种标准超导类型之间的 κ ∼ 1 型域,到达 II 型。在本研究中,我们证明了当电荷载流子态存在多带结构时,无序的影响会更加深远。特别是,当带扩散性互不相同时,类型间域往往会显著扩大,包括κ ≫ 1 的点,而这些点在传统单带超导体中属于深 II 型。我们的发现揭示了非微不足道的无序效应,并极大地补充了早先关于清洁多带超导体中类型间域扩大的结果。
{"title":"Intertype superconductivity evoked by the interplay of disorder and multiple bands","authors":"P. M. Marychev, A. A. Shanenko, A. V. Vagov","doi":"10.1007/s11467-023-1379-y","DOIUrl":"https://doi.org/10.1007/s11467-023-1379-y","url":null,"abstract":"<p>Nonmagnetic impurity scattering is known to shift up the Ginzburg–Landau parameter <i>κ</i> of a superconductor. In this case, when the system is initially in type I, it can change its magnetic response, crossing the intertype domain with <i>κ</i> ∼ 1 between the two standard superconductivity types and arriving at type II. In the present work we demonstrate that the impact of disorder can be much more profound in the presence of the multiband structure of the charge carrier states. In particular, when the band diffusivities differ from each other, the intertype domain tends to expand significantly, including points with <i>κ</i> ≫ 1 that belong to deep type-II in conventional single-band superconductors. Our finding sheds light on the nontrivial disorder effect and significantly complements earlier results on the enlargement of the intertype domain in clean multiband superconductors.\u0000</p>","PeriodicalId":573,"journal":{"name":"Frontiers of Physics","volume":null,"pages":null},"PeriodicalIF":7.5,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139558317","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}