Huang Xue-Feng, Chen Chu, Li Jia-Xin, Zhang Min-Qi, Li Sheng-Ji
The scattering measurement of particulates in gaseous medium is helpful to the understanding of light transmission, laser detection, combustion radiation and atmospheric environment. In order to explore the scattering characteristics of micron/nano -sized particles, this paper proposes to accurately measure the scattering intensity distribution of an individual micron-sized particle/nanocluster by combining laser levitation and scattering measurement methods. An experimental apparatus was first built based on the counter-propagated bi-Bessel beams levitation and scattering test systems. The microparticles/nanoclusters of various matters and sizes were then levitated and their stability was evaluated. Finally, the scattering intensity distribution of levitated particles within 2 π scattering angle was accurately measured at an angular resolution of 9.2″. The forces acting on particles under laser irradiation and the scattering intensity distribution of different particle parameters were simulated and calculated, and compared with experimental results. The influence of noises on the uncertainty of the scattering measurement system was analyzed in depth, including background light, laser beam, reflected light from the walls. The results show that for metallic magnesium and aluminum, whether single particles or clusters, the signal-to-noise ratio of scattering measurements within 2π angle is greater than 20 dB, with a maximum of 94.6 dB. For graphite nanoclusters, the signal-to-noise ratio in the backscattering direction is relatively poor. The influence of levitation instability on the scattering measurement results was estimated in detail, testifying that the influence of levitation instability in the test system on the scattering measurement is ignorable. Metallic magnesium, aluminum, and graphite particles can be stably levitated by the counter-propagated bi-Bessel beams, with a relative instability of less than 0.15. During the levitation, the photophoretic force plays a dominant role; The scattering intensity distribution of an individual micron-sized particle/nanocluster conforms to the scattering characteristics of Mie particles. Microparticles with large refractive index imaginary parts have stronger forward scattering characteristics. The larger the particle size parameter, the stronger the forward scattering effect becomes. The accurate measurement of the scattering intensity distribution of an individual microparticle confirms the versatility and reliability of the levitation scattering test system, providing a new research method for in-depth understanding of the scattering characteristics of substances.
{"title":"Measurement of scattering intensity distribution of individual microparticles/nanoclusters based on laser levitation","authors":"Huang Xue-Feng, Chen Chu, Li Jia-Xin, Zhang Min-Qi, Li Sheng-Ji","doi":"10.7498/aps.72.20230499","DOIUrl":"https://doi.org/10.7498/aps.72.20230499","url":null,"abstract":"The scattering measurement of particulates in gaseous medium is helpful to the understanding of light transmission, laser detection, combustion radiation and atmospheric environment. In order to explore the scattering characteristics of micron/nano -sized particles, this paper proposes to accurately measure the scattering intensity distribution of an individual micron-sized particle/nanocluster by combining laser levitation and scattering measurement methods. An experimental apparatus was first built based on the counter-propagated bi-Bessel beams levitation and scattering test systems. The microparticles/nanoclusters of various matters and sizes were then levitated and their stability was evaluated. Finally, the scattering intensity distribution of levitated particles within 2 π scattering angle was accurately measured at an angular resolution of 9.2″. The forces acting on particles under laser irradiation and the scattering intensity distribution of different particle parameters were simulated and calculated, and compared with experimental results. The influence of noises on the uncertainty of the scattering measurement system was analyzed in depth, including background light, laser beam, reflected light from the walls. The results show that for metallic magnesium and aluminum, whether single particles or clusters, the signal-to-noise ratio of scattering measurements within 2π angle is greater than 20 dB, with a maximum of 94.6 dB. For graphite nanoclusters, the signal-to-noise ratio in the backscattering direction is relatively poor. The influence of levitation instability on the scattering measurement results was estimated in detail, testifying that the influence of levitation instability in the test system on the scattering measurement is ignorable. Metallic magnesium, aluminum, and graphite particles can be stably levitated by the counter-propagated bi-Bessel beams, with a relative instability of less than 0.15. During the levitation, the photophoretic force plays a dominant role; The scattering intensity distribution of an individual micron-sized particle/nanocluster conforms to the scattering characteristics of Mie particles. Microparticles with large refractive index imaginary parts have stronger forward scattering characteristics. The larger the particle size parameter, the stronger the forward scattering effect becomes. The accurate measurement of the scattering intensity distribution of an individual microparticle confirms the versatility and reliability of the levitation scattering test system, providing a new research method for in-depth understanding of the scattering characteristics of substances.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"92 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78399859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As an important quantity in the field of parameter estimation theory and quantum precision measurement, quantum Fisher information (QFI) can not only be used to set the theoretical limit of measurement precision in quantum system, but also be exploited to witness metrological useful quantum entanglement. Recently, it has also been broadly used in many aspects of quantum information science, including quantum metrology, multipartite entanglement structure detection, quantum phase transition, quantum chaos, quantum computation and etc. In this work, from the perspective of quantum measurement, we study the quantum Fisher information of an $N$-qubit WV state ($alpha leftvert W_N rightrangle +sqrt{1-alpha^2}leftvert 00...0rightrangle$) under local operation and Lipkin-Meshkov-Glick (LMG) model. Furthermore, with the general Cramer-Rao lower bound (CRLB) we analyze its performance in high-precision phase measurement. The results show that, under the local operation, the QFI of an $N$-qubit WV state becomes larger with the increase of parameter $alpha$. This not only means the enhanced quantum entanglement, but also implies the powerful ability in high-precision quantum measurement. In the LMG model, as the increase of interactional strength $gamma$ the QFI of $N=3$ qubits WV state gradually tends to be stable and almost not be affected by parameter $alpha$, which relaxes the requirement in the preparation of target state and indicates a great potential in achieving the relatively stable measurement precision. When the number of qubits from WV state is larger than $3$, the QFI of WV state increases with the increase of parameter $alpha$. In the case of fixed parameter $alpha$, we investigate the QFI of an $N$-qubit WV state with respect to interaction strength $gamma$. It is found that the QFI of WV state will increase with the increasing interaction strength, which implies that the greater the interaction strength, the stronger the quantum measurement ability of the WV state. Our work will promote the development of high-precision quantum metrology and especially the interaction-enhanced quantum measurement, and further provide new insights in quantum information processing.
{"title":"Quantum Fisher information of multi-qubit WV entangled state under Lipkin-Meshkov-Glick model","authors":"Li Yan, Ren Zhi-Hong","doi":"10.7498/aps.72.20231179","DOIUrl":"https://doi.org/10.7498/aps.72.20231179","url":null,"abstract":"As an important quantity in the field of parameter estimation theory and quantum precision measurement, quantum Fisher information (QFI) can not only be used to set the theoretical limit of measurement precision in quantum system, but also be exploited to witness metrological useful quantum entanglement. Recently, it has also been broadly used in many aspects of quantum information science, including quantum metrology, multipartite entanglement structure detection, quantum phase transition, quantum chaos, quantum computation and etc. In this work, from the perspective of quantum measurement, we study the quantum Fisher information of an $N$-qubit WV state ($alpha leftvert W_N rightrangle +sqrt{1-alpha^2}leftvert 00...0rightrangle$) under local operation and Lipkin-Meshkov-Glick (LMG) model. Furthermore, with the general Cramer-Rao lower bound (CRLB) we analyze its performance in high-precision phase measurement. The results show that, under the local operation, the QFI of an $N$-qubit WV state becomes larger with the increase of parameter $alpha$. This not only means the enhanced quantum entanglement, but also implies the powerful ability in high-precision quantum measurement. In the LMG model, as the increase of interactional strength $gamma$ the QFI of $N=3$ qubits WV state gradually tends to be stable and almost not be affected by parameter $alpha$, which relaxes the requirement in the preparation of target state and indicates a great potential in achieving the relatively stable measurement precision. When the number of qubits from WV state is larger than $3$, the QFI of WV state increases with the increase of parameter $alpha$. In the case of fixed parameter $alpha$, we investigate the QFI of an $N$-qubit WV state with respect to interaction strength $gamma$. It is found that the QFI of WV state will increase with the increasing interaction strength, which implies that the greater the interaction strength, the stronger the quantum measurement ability of the WV state. Our work will promote the development of high-precision quantum metrology and especially the interaction-enhanced quantum measurement, and further provide new insights in quantum information processing.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"6 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87850354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, it is yet difficult to detect the existence of Martian solid inner core merely based on Mars seismic InSight data. To deal with this problem, our study intends to use the mean density and mean moment of inertia factor to constrain the size and density of Martian solid inner core. Using Mars high-degree gravity field models JGMRO120f and GMM3-120, and considering the recent precession rate, we obtained the mean density and mean moment of inertia factor, which are treated as observed values. Referring to the 4-layers internal structure model of Mars, and considering the 4 parameters including crustal density, mantle density, density of outer core, size and density of inner core, we calculated the modeled values of the Martian mean density and the mean moment of inertia factor. From the minimum residuals between observed and modeled values of mean density as well as that of mean moment of inertia factor, it is found that the two gravity fields models have the same result of distribution of free parameters. As to the optimized values of the free parameters, the two gravity field models even have the same results. Furthermore, the optimized crustal density, mantel density and density of outer core approach other studies, indicating the dependence of our results. Finally, our result demonstrates that Mars likely has a solid inner core with a size close to 840 km, and the density of inner core is near to 6950 kg·m-3. Our result implies that Mars has an inner core not fully composed of pure iron, which is consistent with the recent study that Mars requires a substantial complement of light elements in Martian core. However, it is further needed to constrain the size and composition of Martian inner core due to the non-uniqueness of inversion results. With the improvement of processing technology on the InSight data, it can be further constrained for the size and composition of Martian inner core.
{"title":"Using the second-degree coefficients of gravity field models and the new precession rate to constrain the size and density of Martian inner core","authors":"Zhong Zhen, Wen Qi-Lin, Liang Jin-Fu","doi":"10.7498/aps.72.20221170","DOIUrl":"https://doi.org/10.7498/aps.72.20221170","url":null,"abstract":"Recently, it is yet difficult to detect the existence of Martian solid inner core merely based on Mars seismic InSight data. To deal with this problem, our study intends to use the mean density and mean moment of inertia factor to constrain the size and density of Martian solid inner core. Using Mars high-degree gravity field models JGMRO120f and GMM3-120, and considering the recent precession rate, we obtained the mean density and mean moment of inertia factor, which are treated as observed values. Referring to the 4-layers internal structure model of Mars, and considering the 4 parameters including crustal density, mantle density, density of outer core, size and density of inner core, we calculated the modeled values of the Martian mean density and the mean moment of inertia factor. From the minimum residuals between observed and modeled values of mean density as well as that of mean moment of inertia factor, it is found that the two gravity fields models have the same result of distribution of free parameters. As to the optimized values of the free parameters, the two gravity field models even have the same results. Furthermore, the optimized crustal density, mantel density and density of outer core approach other studies, indicating the dependence of our results. Finally, our result demonstrates that Mars likely has a solid inner core with a size close to 840 km, and the density of inner core is near to 6950 kg·m-3. Our result implies that Mars has an inner core not fully composed of pure iron, which is consistent with the recent study that Mars requires a substantial complement of light elements in Martian core. However, it is further needed to constrain the size and composition of Martian inner core due to the non-uniqueness of inversion results. With the improvement of processing technology on the InSight data, it can be further constrained for the size and composition of Martian inner core.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"122 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88043234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Existing uniform fields are usually based on the special arrangement of the array antenna. The uniform fields generated by flat-top beam shaping in angular far-field area or by point focusing in near-field area are directly subject to the array configuration and cannot be flexibly controlled. This paper presents a uniform field generation method based on the combination of angular spectral domain and improved time reversal techniques. This method is not limited by the array arrangement. It can generate uniform fields of specified size, shape and deflection angle at arbitrary location, including the near field area, in the same array arrangement. In this paper, the reason why this method is not limited by array arrangement is theoretically explained. Secondly, the ability of the fixed array configuration to generate multiple uniform fields is validated numerically. Finally, the time reversal technique of reversal signal amplitude reciprocal weighting is introduced. The problem of deterioration of uniform field flatness caused by amplitude decay and phase delay during the generation of uniform field is solved through this technology. The results show that the quality of the synthesized field is related to the main lobe and sidelobe information of its corresponding angular spectrum domain envelope, and generating arbitrary uniform field must contain at least half of the angular spectrum domain main lobe information and half of the sidelobe information. This method can flexibly control the position, size, shape and deflection angle of one-dimensional and two-dimensional uniform fields, which provides a new approach for flexibly generating uniform fields.
{"title":"Method for the Generation of arbitrary uniform fields based on angular spectral domain and time reversal technique","authors":"An Teng-Yuan, Ding Xiao","doi":"10.7498/aps.72.20230418","DOIUrl":"https://doi.org/10.7498/aps.72.20230418","url":null,"abstract":"Existing uniform fields are usually based on the special arrangement of the array antenna. The uniform fields generated by flat-top beam shaping in angular far-field area or by point focusing in near-field area are directly subject to the array configuration and cannot be flexibly controlled. This paper presents a uniform field generation method based on the combination of angular spectral domain and improved time reversal techniques. This method is not limited by the array arrangement. It can generate uniform fields of specified size, shape and deflection angle at arbitrary location, including the near field area, in the same array arrangement. In this paper, the reason why this method is not limited by array arrangement is theoretically explained. Secondly, the ability of the fixed array configuration to generate multiple uniform fields is validated numerically. Finally, the time reversal technique of reversal signal amplitude reciprocal weighting is introduced. The problem of deterioration of uniform field flatness caused by amplitude decay and phase delay during the generation of uniform field is solved through this technology. The results show that the quality of the synthesized field is related to the main lobe and sidelobe information of its corresponding angular spectrum domain envelope, and generating arbitrary uniform field must contain at least half of the angular spectrum domain main lobe information and half of the sidelobe information. This method can flexibly control the position, size, shape and deflection angle of one-dimensional and two-dimensional uniform fields, which provides a new approach for flexibly generating uniform fields.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"212 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87363755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jiannan Bai, Han Song, Jian-Di Chen, Hai-Yan Han, Yan Dong
Owing to the unique physical characteristics of Rydberg atoms, which play an important role in quantum information and quantum computation, the theoretical and applied research of Rydberg atoms have become one of the hot spots of scientific research in recent years. Thanks to the large polarizability of Rydberg atoms, even a small electric field could cause a considerable electric dipole moment, resulting in a strong dipole-dipole interaction between Rydberg atoms. The multiple excitations of the Rydberg states are strongly inhibited because of the strong dipole interaction between atoms within a mesoscopic interaction (blockade) region. We call this phenomenon the dipole blockade effect. The dipole blockade regime allows us to build single-photon quantum devices, implement quantum gates, generate quantum entanglement, simulate many-body quantum problems and so on.A Rydberg atomic ensemble in the same blockade region can be regarded as a superatom. In the same way, if these atoms trapped in two optical dipole traps, each sub-ensemble can be considered as a sub-superatom which is closely related to the superatom. Based on the fact that two Rydberg sub-superatoms will be strongly correlated due to sharing no more than one excited Rydberg atom, we study the correlated collective excitation and the quantum entanglement between two Rydberg sub-superatoms in the steady state. With the superatom model, the problem of exponentially increasing system size with the number of atoms can be circumvented to a certain extent in studying many-body physics. By solving the two body Lindblad's master equation accurately, we obtain the analytical expressions for the collective excitation probabilities of the two sub-superatoms, and the concurrence measuring the bipartite entanglement between them. Our results show that they are all sensitive to the number of each Rydberg superatom:the bigger (including more atoms) the Rydberg superatom, the higher the collective Rydberg excitation probability; the maximally entangled state can only be obtained with two equal-sized Rydberg superatoms. When this condition is fulfilled, the generation of mesoscopic entanglement could be achieved by adding the number of each Rydberg superatom. This may provide an attractive platform to study the quantum-classical correspondence and have potential promising applications in quantum information processing.
{"title":"Correlated collective excitation and quantum entanglement between two Rydberg superatoms in the steady state","authors":"Jiannan Bai, Han Song, Jian-Di Chen, Hai-Yan Han, Yan Dong","doi":"10.7498/aps.72.20222030","DOIUrl":"https://doi.org/10.7498/aps.72.20222030","url":null,"abstract":"Owing to the unique physical characteristics of Rydberg atoms, which play an important role in quantum information and quantum computation, the theoretical and applied research of Rydberg atoms have become one of the hot spots of scientific research in recent years. Thanks to the large polarizability of Rydberg atoms, even a small electric field could cause a considerable electric dipole moment, resulting in a strong dipole-dipole interaction between Rydberg atoms. The multiple excitations of the Rydberg states are strongly inhibited because of the strong dipole interaction between atoms within a mesoscopic interaction (blockade) region. We call this phenomenon the dipole blockade effect. The dipole blockade regime allows us to build single-photon quantum devices, implement quantum gates, generate quantum entanglement, simulate many-body quantum problems and so on.A Rydberg atomic ensemble in the same blockade region can be regarded as a superatom. In the same way, if these atoms trapped in two optical dipole traps, each sub-ensemble can be considered as a sub-superatom which is closely related to the superatom. Based on the fact that two Rydberg sub-superatoms will be strongly correlated due to sharing no more than one excited Rydberg atom, we study the correlated collective excitation and the quantum entanglement between two Rydberg sub-superatoms in the steady state. With the superatom model, the problem of exponentially increasing system size with the number of atoms can be circumvented to a certain extent in studying many-body physics. By solving the two body Lindblad's master equation accurately, we obtain the analytical expressions for the collective excitation probabilities of the two sub-superatoms, and the concurrence measuring the bipartite entanglement between them. Our results show that they are all sensitive to the number of each Rydberg superatom:the bigger (including more atoms) the Rydberg superatom, the higher the collective Rydberg excitation probability; the maximally entangled state can only be obtained with two equal-sized Rydberg superatoms. When this condition is fulfilled, the generation of mesoscopic entanglement could be achieved by adding the number of each Rydberg superatom. This may provide an attractive platform to study the quantum-classical correspondence and have potential promising applications in quantum information processing.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87553295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Li Wan-jiao, Guan Yun-Xia, Bao Xi, Wang Cheng, Song Jia-Yi, Xu Shuang, Peng ke-Ao, Chen Li-jia, Niu Lian-Bin
Tandem organic electroluminescent devices (OLEDs) have attracted widespread attention due to their long lifetime and high current efficiency. In this study, a double-emitting unit tandem OLED was fabricated using Alq3/HAT-CN as an interconnect layer. Its photovoltaic properties and exciton regulation mechanism were investigated. The results show that the luminance (11189.86 cd/m2) and efficiency (13.85 cd/A) of the tandem OLED reached 2.7 times that of the single EL unit OLED (luminance and efficiency of 4007.14 cd/m2 and 5.00 cd/A, respectively) at a current density of 80 mA/cm2. This proves that Alq3/HAT-CN is an efficient interconnect layer. At room temperature, the polaron pair undergoes intersystem crossing (ISC) due to hyperfine interaction (HFI) when a magnetic field is applied to the device. This increases the concentration of the triplet exciton (T1), which favours charg the scattering. The result is a rapid increase in the low magnetic field and a slow increase in the high magnetic field of the MEL. When the injection current strength is constant, there is less uncompounded charge in the Alq3/HAT-CN device than in other connected layer devices. Triplet-charge annihilation (TQA) is weak, resulting in a relative increase in the concentration of T1, which is not involved in TQA. This suppresses the ISC and leads to a minimal increase in the MEL. As the current strength increases, the T1 concentration increases, causing TQA toincrease and ISC to decrease. Since TQA is related to charge and T1 concentration, lowering the temperature decreases the carrier mobility in the device, resulting in a relative decrease in charge concentration and a weakening of TQA. Lowering the temperature decreases the quenching of thermal phonons and increases the concentration of T1 while extending its lifetime, resulting in enhanced triplet-triplet annihilation (TTA). At low temperatures, the high magnetic field shape of the MEL changes from slowly increasing to rapidly decrease. Therefore, the concentration of T1 can be regulated by varying the current strength and temperature, which further affects the strength of ISC, TQA and TTA, and the luminescence and efficiency of the device can be effectively improved by reducing TQA and ISC. This work is important for the understanding of the luminescence mechanism of small molecule tandem devices and investigating the investigation of the mechanism for improving their photovoltaic performance.
{"title":"Investigation of the exciton regulation mechanism of Alq3/HAT-CN tandem electroluminescent devices","authors":"Li Wan-jiao, Guan Yun-Xia, Bao Xi, Wang Cheng, Song Jia-Yi, Xu Shuang, Peng ke-Ao, Chen Li-jia, Niu Lian-Bin","doi":"10.7498/aps.72.20230973","DOIUrl":"https://doi.org/10.7498/aps.72.20230973","url":null,"abstract":"Tandem organic electroluminescent devices (OLEDs) have attracted widespread attention due to their long lifetime and high current efficiency. In this study, a double-emitting unit tandem OLED was fabricated using Alq3/HAT-CN as an interconnect layer. Its photovoltaic properties and exciton regulation mechanism were investigated. The results show that the luminance (11189.86 cd/m2) and efficiency (13.85 cd/A) of the tandem OLED reached 2.7 times that of the single EL unit OLED (luminance and efficiency of 4007.14 cd/m2 and 5.00 cd/A, respectively) at a current density of 80 mA/cm2. This proves that Alq3/HAT-CN is an efficient interconnect layer. At room temperature, the polaron pair undergoes intersystem crossing (ISC) due to hyperfine interaction (HFI) when a magnetic field is applied to the device. This increases the concentration of the triplet exciton (T1), which favours charg the scattering. The result is a rapid increase in the low magnetic field and a slow increase in the high magnetic field of the MEL. When the injection current strength is constant, there is less uncompounded charge in the Alq3/HAT-CN device than in other connected layer devices. Triplet-charge annihilation (TQA) is weak, resulting in a relative increase in the concentration of T1, which is not involved in TQA. This suppresses the ISC and leads to a minimal increase in the MEL. As the current strength increases, the T1 concentration increases, causing TQA toincrease and ISC to decrease. Since TQA is related to charge and T1 concentration, lowering the temperature decreases the carrier mobility in the device, resulting in a relative decrease in charge concentration and a weakening of TQA. Lowering the temperature decreases the quenching of thermal phonons and increases the concentration of T1 while extending its lifetime, resulting in enhanced triplet-triplet annihilation (TTA). At low temperatures, the high magnetic field shape of the MEL changes from slowly increasing to rapidly decrease. Therefore, the concentration of T1 can be regulated by varying the current strength and temperature, which further affects the strength of ISC, TQA and TTA, and the luminescence and efficiency of the device can be effectively improved by reducing TQA and ISC. This work is important for the understanding of the luminescence mechanism of small molecule tandem devices and investigating the investigation of the mechanism for improving their photovoltaic performance.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"31 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76449979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We used admittance spectroscopy to characterize the energy distribution of defects in CIGSe solar cells before and after annealing to investigate the mechanism of the annealing process improving battery performance. In this article, we annealed the prepared CIGSe solar cells in compressed air at 150℃ for 10 minutes. We conducted dark I-V, C-V, admittance spectroscopy, and illumination I-V tests on CIGSe solar cells before and after annealing to characterize the changes in battery performance before and after annealing. The test results of dark I-V characteristics showed that the reverse dark current of CIGSe solar cells decreased by about an order of magnitude after annealing, and the ideal factor of the cells also decreased from 2.16 before annealing to 1.85 after annealing. This means that the annealing process reduces the recombination of carriers in CIGSe solar cells. Under reverse bias, the capacitance of CIGSe solar cells is higher than that after annealing, and their C-V characteristics are linearly fitted with 1/C2 vs. V. The fitting results show that the slope of the curve increases after annealing, which means that the annealing process leads to a decrease in the free carrier concentration in the absorption layer of CIGSe solar cells, that is, a decrease in the carrier concentration contributed by defects after annealing. In addition, the built-in potentials before and after annealing of CIGSe solar cells were also obtained through fitting, which are 0.52V and 0.64V, respectively. The admittance spectrum test results of CIGSe solar cells before and after annealing showed that the defect activation energy in the absorption layer significantly decreased after annealing, but the defect concentration remained almost unchanged. The decrease in defect activation energy means that the Shockley Read Hall (SRH) recombination probability of defects in copper indium gallium selenium solar cells is reduced. In addition, the test results of the optical I-V characteristics of the battery indicate that the open circuit voltage and parallel resistance of the battery significantly increase after annealing, which is consistent with the test results of the dark I-V characteristics, C-V characteristics, and admittance spectroscopy of the solar cell. Therefore, the annealing process of CIGSe solar cells leads to a weakening of the SRH recombination of carriers in the absorption layer of the battery, thereby improving the performance of the solar cell's performances.
利用导纳光谱对CIGSe太阳能电池退火前后缺陷的能量分布进行了表征，探讨了退火工艺改善电池性能的机理。在本文中，我们将制备好的CIGSe太阳能电池在压缩空气中150℃退火10分钟。我们对退火前后的CIGSe太阳能电池进行了暗I-V、C-V、导纳光谱和照明I-V测试，表征了退火前后电池性能的变化。暗I-V特性测试结果表明，CIGSe太阳能电池的反向暗电流在退火后下降了约一个数量级，电池的理想因子也从退火前的2.16下降到退火后的1.85。这意味着退火过程减少了载流子在CIGSe太阳能电池中的复合。在反向偏压下，CIGSe太阳电池的电容高于退火后的电容，其C-V特性与1/C2 vs. v呈线性拟合。拟合结果表明，退火后曲线斜率增大，说明退火过程导致CIGSe太阳电池吸收层中自由载流子浓度降低，即退火后缺陷贡献的载流子浓度降低。此外，通过拟合得到了CIGSe太阳能电池退火前后的内嵌电势，分别为0.52V和0.64V。退火前后CIGSe太阳电池的导纳谱测试结果表明，退火后吸收层缺陷活化能明显降低，但缺陷浓度基本保持不变。缺陷激活能的降低意味着铜铟镓硒太阳电池中缺陷的Shockley Read Hall (SRH)重组概率降低。此外，该电池的光学I-V特性测试结果表明，退火后电池的开路电压和并联电阻显著增加，这与该太阳能电池的暗I-V特性、C-V特性和导纳光谱测试结果一致。因此，CIGSe太阳能电池的退火工艺导致电池吸收层载流子的SRH复合减弱，从而提高了太阳能电池的性能。
{"title":"Characterization of the Defect in CIGS Solar Cell by Admittance Spectroscopy","authors":"Rui Jia, Xiaorang Tian","doi":"10.7498/aps.72.20230292","DOIUrl":"https://doi.org/10.7498/aps.72.20230292","url":null,"abstract":"We used admittance spectroscopy to characterize the energy distribution of defects in CIGSe solar cells before and after annealing to investigate the mechanism of the annealing process improving battery performance. In this article, we annealed the prepared CIGSe solar cells in compressed air at 150℃ for 10 minutes. We conducted dark I-V, C-V, admittance spectroscopy, and illumination I-V tests on CIGSe solar cells before and after annealing to characterize the changes in battery performance before and after annealing. The test results of dark I-V characteristics showed that the reverse dark current of CIGSe solar cells decreased by about an order of magnitude after annealing, and the ideal factor of the cells also decreased from 2.16 before annealing to 1.85 after annealing. This means that the annealing process reduces the recombination of carriers in CIGSe solar cells. Under reverse bias, the capacitance of CIGSe solar cells is higher than that after annealing, and their C-V characteristics are linearly fitted with 1/C2 vs. V. The fitting results show that the slope of the curve increases after annealing, which means that the annealing process leads to a decrease in the free carrier concentration in the absorption layer of CIGSe solar cells, that is, a decrease in the carrier concentration contributed by defects after annealing. In addition, the built-in potentials before and after annealing of CIGSe solar cells were also obtained through fitting, which are 0.52V and 0.64V, respectively. The admittance spectrum test results of CIGSe solar cells before and after annealing showed that the defect activation energy in the absorption layer significantly decreased after annealing, but the defect concentration remained almost unchanged. The decrease in defect activation energy means that the Shockley Read Hall (SRH) recombination probability of defects in copper indium gallium selenium solar cells is reduced. In addition, the test results of the optical I-V characteristics of the battery indicate that the open circuit voltage and parallel resistance of the battery significantly increase after annealing, which is consistent with the test results of the dark I-V characteristics, C-V characteristics, and admittance spectroscopy of the solar cell. Therefore, the annealing process of CIGSe solar cells leads to a weakening of the SRH recombination of carriers in the absorption layer of the battery, thereby improving the performance of the solar cell's performances.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"332 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76588495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Convergence-zone (CZ) sound propagation is one of the most important hydro-acoustic phenomenons in the deep ocean, that allows long-range transmission of acoustic signals with high intensity and low distortion. Accurate prediction and identification of CZ is of great significance for remote detection or communication, but there is still no standard definition in sense of mathematical physics for convergence zone. Especially on the issue of systematic error of computation introduced by the earth curvature, with no exact propagation model, curvature-correction methods always lead to imprecision of the ray phase. In previous research work, we realize that the Riemannian geometric meaning of the caustics phenomena caused by ray convergence is that the caustic points are equivalent to the conjugate points, which form on geodesics with positive section curvature. In this paper, we presents a spherical layered acoustic ray propagation model for CZ based on the Riemannian geometric theory. With direct computation in the curved manifolds of the earth instead of in the European space, a Riemannian geometric description of CZ is provided for the first time, on the basis of comprehensive analysis about it’s characteristics. And it shows that the mathematical expression of section curvature adds an additional item $frac{{hat c(l)hat c'(l)}}{l}$ after considering the earth curvature, which reflects the influence of the earth curvature on the ray topology and CZ. By means of Jacobi field theory of Riemannian geometry, computational rule and methods of the location and distance of CZ in deep water are proposed. Taking the Munk sound speed profile as an typical example, the new Riemannian geometric model of CZ is compared with the normal mode and curvature-correction method. Simulation and analysis shows that the Riemannian geometric model of CZ given in this paper is a mathematical form naturally considering the earth curvature with theoretical accuracy, which lays more solid scientific foundations for research of convergence zone. Moreover, we find that the location of CZ moves towards sound source when considering the earth curvature, and the width of CZ near the sea surface increases first and then decreases with sound propagation. The maximum width is about 20 km and the minimum is about 4 km.
{"title":"Riemannian Geometric Modeling of Underwater Acoustic Ray Propagation · Application——Riemannian Geometric Model of Convergence Zone in the Deep Ocean","authors":"Ma S Q, Guo X J, Zhang L L, Lan Q, Huang C X","doi":"10.7498/aps.72.20221495","DOIUrl":"https://doi.org/10.7498/aps.72.20221495","url":null,"abstract":"Convergence-zone (CZ) sound propagation is one of the most important hydro-acoustic phenomenons in the deep ocean, that allows long-range transmission of acoustic signals with high intensity and low distortion. Accurate prediction and identification of CZ is of great significance for remote detection or communication, but there is still no standard definition in sense of mathematical physics for convergence zone. Especially on the issue of systematic error of computation introduced by the earth curvature, with no exact propagation model, curvature-correction methods always lead to imprecision of the ray phase. In previous research work, we realize that the Riemannian geometric meaning of the caustics phenomena caused by ray convergence is that the caustic points are equivalent to the conjugate points, which form on geodesics with positive section curvature. In this paper, we presents a spherical layered acoustic ray propagation model for CZ based on the Riemannian geometric theory. With direct computation in the curved manifolds of the earth instead of in the European space, a Riemannian geometric description of CZ is provided for the first time, on the basis of comprehensive analysis about it’s characteristics. And it shows that the mathematical expression of section curvature adds an additional item $frac{{hat c(l)hat c'(l)}}{l}$ after considering the earth curvature, which reflects the influence of the earth curvature on the ray topology and CZ. By means of Jacobi field theory of Riemannian geometry, computational rule and methods of the location and distance of CZ in deep water are proposed. Taking the Munk sound speed profile as an typical example, the new Riemannian geometric model of CZ is compared with the normal mode and curvature-correction method. Simulation and analysis shows that the Riemannian geometric model of CZ given in this paper is a mathematical form naturally considering the earth curvature with theoretical accuracy, which lays more solid scientific foundations for research of convergence zone. Moreover, we find that the location of CZ moves towards sound source when considering the earth curvature, and the width of CZ near the sea surface increases first and then decreases with sound propagation. The maximum width is about 20 km and the minimum is about 4 km.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"462 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76691060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Underwater sound propagation models are generally established from the extrinsic perspective, that is, embedding acoustic channels in Euclidean space with fixed coordinate system. Riemannian geometry is intrinsic for curved space, that can describe the essential properties of background manifolds. The underwater acoustic Gaussian beam was originally adopted from seismology. Till now it is the most important method used in acoustic ray based modeling and applications. Due to the advantages of Gaussian beam method over the traditional ray counterpart, it is the mainstream technology of ray propagation computational software such as the famous Bellhop. With the assumption of Euclidean space, it is hard to grasp the naturally curved characteristics of the Gaussian beam. In this paper, we propose the Riemannian geometry theory of underwater acoustic ray propagation, and obtain the following results : (1) The Riemannian geometric intrinsic forms of the eikonal equation, paraxial ray equation and the Gaussian beam under radially symmetric acoustic propagation environments are established, that provide a Riemannian geometric interpretation of the Gaussian beam. In fact, the underwater acoustic eikonal equation is equivalent to the geodesic equation in Riemannian manifolds, and the intrinsic geometric spreading of the Gaussian beam corresponds to the lateral deviation of geodesic curve along the Jacobian field. (2) Some geometric and topological properties of acoustic ray about conjugate points and section curvature are acquired by the Jacobi field theory, indicating that the convergence of ray beam corresponds to the intersection of geodesics at the conjugate point with positive section curvature. (3)The specific modeling method under horizontal stratified and distance-related environment is presented using the above theory. And we point out that the method proposed here is also applicable to other radially symmetric acoustic propagation environments. (4) Simulation and comparative analysis of three typical underwater acoustic propagation examples, confirms the feasibility of the Riemannian geometric model for underwater acoustic propagation. And shows that the Riemannian geometric model has exact mathematical physics meaning over the Euclidean space method adopted by the Bellhop model. The basic theory given in this paper can be extended to curved surface, three-dimensional and other complex propagation environments. And especially it lays a theoretical foundation for the further research of long-range acoustic propagation considering curvature of the earth.
{"title":"Riemannian Geometric Modeling of Underwater Acoustic Ray Propagation · Basic Theory","authors":"Guo X J, Ma S Q, Zhang L L, Lan Q, Huang C X","doi":"10.7498/aps.72.20221451","DOIUrl":"https://doi.org/10.7498/aps.72.20221451","url":null,"abstract":"Underwater sound propagation models are generally established from the extrinsic perspective, that is, embedding acoustic channels in Euclidean space with fixed coordinate system. Riemannian geometry is intrinsic for curved space, that can describe the essential properties of background manifolds. The underwater acoustic Gaussian beam was originally adopted from seismology. Till now it is the most important method used in acoustic ray based modeling and applications. Due to the advantages of Gaussian beam method over the traditional ray counterpart, it is the mainstream technology of ray propagation computational software such as the famous Bellhop. With the assumption of Euclidean space, it is hard to grasp the naturally curved characteristics of the Gaussian beam. In this paper, we propose the Riemannian geometry theory of underwater acoustic ray propagation, and obtain the following results : (1) The Riemannian geometric intrinsic forms of the eikonal equation, paraxial ray equation and the Gaussian beam under radially symmetric acoustic propagation environments are established, that provide a Riemannian geometric interpretation of the Gaussian beam. In fact, the underwater acoustic eikonal equation is equivalent to the geodesic equation in Riemannian manifolds, and the intrinsic geometric spreading of the Gaussian beam corresponds to the lateral deviation of geodesic curve along the Jacobian field. (2) Some geometric and topological properties of acoustic ray about conjugate points and section curvature are acquired by the Jacobi field theory, indicating that the convergence of ray beam corresponds to the intersection of geodesics at the conjugate point with positive section curvature. (3)The specific modeling method under horizontal stratified and distance-related environment is presented using the above theory. And we point out that the method proposed here is also applicable to other radially symmetric acoustic propagation environments. (4) Simulation and comparative analysis of three typical underwater acoustic propagation examples, confirms the feasibility of the Riemannian geometric model for underwater acoustic propagation. And shows that the Riemannian geometric model has exact mathematical physics meaning over the Euclidean space method adopted by the Bellhop model. The basic theory given in this paper can be extended to curved surface, three-dimensional and other complex propagation environments. And especially it lays a theoretical foundation for the further research of long-range acoustic propagation considering curvature of the earth.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"2 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76898557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-energy nuclear physics aims at exploring and understanding the physics of matter constituted by quark and gluon. However, it is intrinsically diffculty to simulate high-energy nuclear physics from the first principle based on quantum chromodynamics with classical computers. In recent years, quantum computing has received intensive attention because it is expected to provide an ultimate solution for simulating high-energy nuclear physics. In this paper, we firstly review recent advances in quantum simulation of high-energy nuclear physics. Then some standard quantum algorithms will be introduced, such as state preparation and measurements of light-cone correlation function. Lastly, we demonstrate the advantage of quantum computing for solving the real-time evolution and the sign problems by studying hadronic scattering amplitude and phase structure of finitetemperature and finite-density matter, respectively.
{"title":"High-energy nuclear physics by quantum computing","authors":"Li Tian-Yin, Xing Hong-Xi, Zhang Dan-Bo","doi":"10.7498/aps.72.20230907","DOIUrl":"https://doi.org/10.7498/aps.72.20230907","url":null,"abstract":"High-energy nuclear physics aims at exploring and understanding the physics of matter constituted by quark and gluon. However, it is intrinsically diffculty to simulate high-energy nuclear physics from the first principle based on quantum chromodynamics with classical computers. In recent years, quantum computing has received intensive attention because it is expected to provide an ultimate solution for simulating high-energy nuclear physics. In this paper, we firstly review recent advances in quantum simulation of high-energy nuclear physics. Then some standard quantum algorithms will be introduced, such as state preparation and measurements of light-cone correlation function. Lastly, we demonstrate the advantage of quantum computing for solving the real-time evolution and the sign problems by studying hadronic scattering amplitude and phase structure of finitetemperature and finite-density matter, respectively.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"2 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72706742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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