For the n-qubit stochastic open quantum systems,based on the Lyapunov stability theorem and LaSalle’s invariant set principle,a pure state switching control based on on-line estimated state feedback(short for OQST-SF...For the n-qubit stochastic open quantum systems,based on the Lyapunov stability theorem and LaSalle’s invariant set principle,a pure state switching control based on on-line estimated state feedback(short for OQST-SFC)is proposed to realize the state transition the pure state of the target state including eigenstate and superposition state.The proposed switching control consists of a constant control and a control law designed based on the Lyapunov method,in which the Lyapunov function is the state distance of the system.The constant control is used to drive the system state from an initial state to the convergence domain only containing the target state,and a Lyapunov-based control is used to make the state enter the convergence domain and then continue to converge to the target state.At the same time,the continuous weak measurement of quantum system and the quantum state tomography method based on the on-line alternating direction multiplier(QST-OADM)are used to obtain the system information and estimate the quantum state which is used as the input of the quantum system controller.Then,the pure state feedback switching control method based on the on-line estimated state feedback is realized in an n-qubit stochastic open quantum system.The complete derivation process of n-qubit QST-OADM algorithm is given;Through strict theoretical proof and analysis,the convergence conditions to ensure any initial state of the quantum system to converge the target pure state are given.The proposed control method is applied to a 2-qubit stochastic open quantum system for numerical simulation experiments.Four possible different position cases between the initial estimated state and that of the controlled system are studied and discussed,and the performances of the state transition under the corresponding cases are analyzed.展开更多
In this paper, the problem of high mobility channel estimation in the Long-Term Evolution for Railway (LTE-R) communication system is investigated. By using a Basis Expansion Model (BEM), the channel impulse response ...In this paper, the problem of high mobility channel estimation in the Long-Term Evolution for Railway (LTE-R) communication system is investigated. By using a Basis Expansion Model (BEM), the channel impulse response is modeled as the sum of several basis functions multiplied by coefficients. By estimating the basis function coefficients, the fast time-varying channel can be approximated. In order to reduce the estimation error resulting from the high frequency basis function, the Generalized Complex Exponential BEM (GCE-BEM) is modified to form an Improved GCE-BEM (IGCE-BEM) by adding a correction coefficient to the basis function. Moreover, an Improved Baseline Tilting (IBT) method is proposed to reduce the Gibbs effect. In addition, linear interpolation, Gauss interpolation, and three-order Hermite interpolation are adopted to obtain the channel impulse response at non pilot locations based on the channel estimation results at pilot positions. The simulation results show that the IGCE-BEM outperforms the CE-BEM and GCE-BEM in terms of the Normalized Mean Squared Error (NMSE). The IB T method is better than the BT method in reducing the Gibbs effect. In addition, combined with the IBT, the IGCE-BEM also has low NMSE under high moving speed and high noise power. The performance of the threeorder Hermite interpolation method is higher than that of the linear interpolation and Gauss interpolation approaches.展开更多
Collective cell migration plays critical roles in various developmental,physiological,and pathological processes such as morphogenesis,wound healing,and tumor metastasis(Friedl and Gilmour,2009).During collective migr...Collective cell migration plays critical roles in various developmental,physiological,and pathological processes such as morphogenesis,wound healing,and tumor metastasis(Friedl and Gilmour,2009).During collective migration,each coherent group of associated cells needs to interpret external directional signal and convert it into a front-back asymmetry across a collective group(Rorth,2011).But the underlying mechanism for the establishment and maintenance of front-back asymmetry during collective migration is still not well understood.展开更多
This erratum clarifies information in the Letter to the Editor“Actin polymerization induces mitochondrial distribution during collective cell migration”by Qu et al.(2023).In the section for the list of author names,...This erratum clarifies information in the Letter to the Editor“Actin polymerization induces mitochondrial distribution during collective cell migration”by Qu et al.(2023).In the section for the list of author names,“Chen Qu,Yating Kan,Hui Zuo,Mengqi Wu,Zhixiang Dong,Xinyi Wang,Qing Zhang,Heng Wang,Dou Wang,Jiong Chen”should be“Chen Qu,Yating Kan,Xinyi Wang,Hui Zuo,Mengqi Wu,Zhixiang Dong,Qing Zhang,Heng Wang,Dou Wang,Jiong Chen”.展开更多
基金supported by the National Natural Science Foundation of China(62473354).
文摘For the n-qubit stochastic open quantum systems,based on the Lyapunov stability theorem and LaSalle’s invariant set principle,a pure state switching control based on on-line estimated state feedback(short for OQST-SFC)is proposed to realize the state transition the pure state of the target state including eigenstate and superposition state.The proposed switching control consists of a constant control and a control law designed based on the Lyapunov method,in which the Lyapunov function is the state distance of the system.The constant control is used to drive the system state from an initial state to the convergence domain only containing the target state,and a Lyapunov-based control is used to make the state enter the convergence domain and then continue to converge to the target state.At the same time,the continuous weak measurement of quantum system and the quantum state tomography method based on the on-line alternating direction multiplier(QST-OADM)are used to obtain the system information and estimate the quantum state which is used as the input of the quantum system controller.Then,the pure state feedback switching control method based on the on-line estimated state feedback is realized in an n-qubit stochastic open quantum system.The complete derivation process of n-qubit QST-OADM algorithm is given;Through strict theoretical proof and analysis,the convergence conditions to ensure any initial state of the quantum system to converge the target pure state are given.The proposed control method is applied to a 2-qubit stochastic open quantum system for numerical simulation experiments.Four possible different position cases between the initial estimated state and that of the controlled system are studied and discussed,and the performances of the state transition under the corresponding cases are analyzed.
基金the National Natural Science Foundation of China (No. U1405251, No. 61401100, No. 61601126, and No. 61571129)the Natural Science Foundation of Fujian Province (No. 2015J05122).
文摘In this paper, the problem of high mobility channel estimation in the Long-Term Evolution for Railway (LTE-R) communication system is investigated. By using a Basis Expansion Model (BEM), the channel impulse response is modeled as the sum of several basis functions multiplied by coefficients. By estimating the basis function coefficients, the fast time-varying channel can be approximated. In order to reduce the estimation error resulting from the high frequency basis function, the Generalized Complex Exponential BEM (GCE-BEM) is modified to form an Improved GCE-BEM (IGCE-BEM) by adding a correction coefficient to the basis function. Moreover, an Improved Baseline Tilting (IBT) method is proposed to reduce the Gibbs effect. In addition, linear interpolation, Gauss interpolation, and three-order Hermite interpolation are adopted to obtain the channel impulse response at non pilot locations based on the channel estimation results at pilot positions. The simulation results show that the IGCE-BEM outperforms the CE-BEM and GCE-BEM in terms of the Normalized Mean Squared Error (NMSE). The IB T method is better than the BT method in reducing the Gibbs effect. In addition, combined with the IBT, the IGCE-BEM also has low NMSE under high moving speed and high noise power. The performance of the threeorder Hermite interpolation method is higher than that of the linear interpolation and Gauss interpolation approaches.
基金supported by grants from the National Natural Science Foundation of China(31970743)the Fundamental Research Funds for the Central Universities(021414380524)to JC+1 种基金grants from the National Natural Science Foundation of China(31900563)Natural Science Foundation of Jiangsu Province(BK20190303)to HW。
文摘Collective cell migration plays critical roles in various developmental,physiological,and pathological processes such as morphogenesis,wound healing,and tumor metastasis(Friedl and Gilmour,2009).During collective migration,each coherent group of associated cells needs to interpret external directional signal and convert it into a front-back asymmetry across a collective group(Rorth,2011).But the underlying mechanism for the establishment and maintenance of front-back asymmetry during collective migration is still not well understood.
文摘This erratum clarifies information in the Letter to the Editor“Actin polymerization induces mitochondrial distribution during collective cell migration”by Qu et al.(2023).In the section for the list of author names,“Chen Qu,Yating Kan,Hui Zuo,Mengqi Wu,Zhixiang Dong,Xinyi Wang,Qing Zhang,Heng Wang,Dou Wang,Jiong Chen”should be“Chen Qu,Yating Kan,Xinyi Wang,Hui Zuo,Mengqi Wu,Zhixiang Dong,Qing Zhang,Heng Wang,Dou Wang,Jiong Chen”.