The influence of the disturbance caused by the imperfection of the engineering coupling constants in the perfect state transfer is calculated. The results show that the fidelity for the perfect state transfer is serio...The influence of the disturbance caused by the imperfection of the engineering coupling constants in the perfect state transfer is calculated. The results show that the fidelity for the perfect state transfer is seriously affected by the errors occurring near the input and output spins. Such results are helpful for the realization of the perfect state transfer in the case where there exist errors in experiments.展开更多
We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum ...We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.展开更多
Recently,there are extensive studies on perfect state transfer(PST for short)on graphs due to their significant applications in quantum information processing and quantum computations.However,there is not any general ...Recently,there are extensive studies on perfect state transfer(PST for short)on graphs due to their significant applications in quantum information processing and quantum computations.However,there is not any general characterization of graphs that have PST in literature.In this paper,the authors present a depiction on weighted abelian Cayley graphs having PST.They give a unified approach to describe the periodicity and the existence of PST on some specific graphs.展开更多
We investigate the effect of phase shift on the perfect state transfer through two parallel one-dimensional ring-shaped spin chains. We find that the total success probability can be significantly enhanced by phase sh...We investigate the effect of phase shift on the perfect state transfer through two parallel one-dimensional ring-shaped spin chains. We find that the total success probability can be significantly enhanced by phase shift control when the communication channel consists of two odd chains. The average time to gain unit success probability is discussed, showing that a proper phase shift can be used to enhance the efficiency of state transmission.展开更多
In this paper,we give some sufficient conditions for extended neighborhood coronas to have Laplacian perfect state transfer.We also give some conditions for extended neighborhood coronas to be periodic.
The quantum state transmission through the medium of high-dimensional many-particle system （boson or spinless fermion） is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonia...The quantum state transmission through the medium of high-dimensional many-particle system （boson or spinless fermion） is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonian matches the symmetry of a fermion or boson system in a certain fashion, a perfect quantum state transfer can be implemented without any operation on the medium with pre-engineered nearest neighbor （NN）. We also study a simple but realistic near half-filled tight-bindlng fermion system wlth uniform NN hopping integral. We show that an arbitrary many-particle state near the fermi surface can be perfectly transferred to its translational counterpart.展开更多
优异的光学吸收器一直具备着高品质因数和完美吸收的特性,然而,这类吸收器通常会受到传统表面等离子体共振带来的欧姆损耗,制约其在实际应用中的吸收性能.本文提出了一种基于法布里-珀罗腔的可调谐连续域束缚态(bound state in the cont...优异的光学吸收器一直具备着高品质因数和完美吸收的特性,然而,这类吸收器通常会受到传统表面等离子体共振带来的欧姆损耗,制约其在实际应用中的吸收性能.本文提出了一种基于法布里-珀罗腔的可调谐连续域束缚态(bound state in the continuum,BIC),通过调整模型的参数,可将BIC可以转变为准BIC,在连续谱中实现了100%的完美吸收.在本文中,采用干涉理论探究了影响完美吸收的因素,用耦合模理论和阻抗匹配理论对准BIC进行理论计算,采用电场和磁场理论解释了吸收器完美吸收的物理机制.与传统吸收器相比,该吸收器具有优异的结构参数鲁棒性和广泛的BIC调控范围.更重要的是,该吸收器具有出色的传感性能,其最大灵敏度可达34 nm/RIU,最大品质因数为9.5.最后,该吸收器还实现了双频的开光性能,其中双频开关的最大调制深度和最小插入损耗分别为99.4%和0.0004 dB.这些研究结果在光子学、光通信、传感器技术等领域具有重要意义.展开更多
Perfect state transfer(PST)has great significance due to its applications in quantum information processing and quantum computation.The main problem we study in this paper is to determine whether the two-fold Cayley t...Perfect state transfer(PST)has great significance due to its applications in quantum information processing and quantum computation.The main problem we study in this paper is to determine whether the two-fold Cayley tree,an extension of the Cayley tree,admits perfect state transfer between two roots using quantum walks.We show that PST can be achieved by means of the so-called nonrepeating quantum walk[Phys.Rev.A 89042332(2014)]within time steps that are the distance between the two roots;while both the continuous-time quantum walk and the typical discrete-time quantum walk with Grover coin approaches fail.Our results suggest that in some cases the dynamics of a discrete-time quantum walk may be much richer than that of the continuous-time quantum walk.展开更多
A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay syst...A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay system over Nakagami-m fading channels with perfect and imperfect channel state information (CSI). In order to maximize spectral efficiency (SE) under delay and packet error rate (PER) performance constraints, a state transition model and an optimization framework with perfect CSI are presented. Then the framework is extended to cooperative relay system with imperfect CSI. The numerical results show that the scheme can achieve maximum SE while satisfying transmitting delay requirements. Compared with the imperfect CSI, the average PER with perfect CSI is much lower and the spectral efficiency is much higher.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10374010）.Acknowledgement Liu Dan would like to thank Professor Long Gui- Lu of Tsinghua University for helpful discussions.
文摘The influence of the disturbance caused by the imperfection of the engineering coupling constants in the perfect state transfer is calculated. The results show that the fidelity for the perfect state transfer is seriously affected by the errors occurring near the input and output spins. Such results are helpful for the realization of the perfect state transfer in the case where there exist errors in experiments.
基金Project supported by the National Natural Science Foundation of China(Grant No.12174300)the Natural Science Foundation of Hubei Province of China(Grant No.2020CFB748)+2 种基金the Natural Science Foundation of Shandong Province of China(Grant Nos.ZR2021MA042 and ZR2021MA078)the Program for Science and Technology Innovation Team in Colleges of Hubei Province of China(Grant No.T2021012)the Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(Grant Nos.BK202113,BK201906,and BK202008)。
文摘We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.
基金supported by the National Natural Science Foundation of China(Nos.11771007,11601003,11801007,12031011)Natural Science Foundation of Anhui Province(No.1808085MA17)。
文摘Recently,there are extensive studies on perfect state transfer(PST for short)on graphs due to their significant applications in quantum information processing and quantum computations.However,there is not any general characterization of graphs that have PST in literature.In this paper,the authors present a depiction on weighted abelian Cayley graphs having PST.They give a unified approach to describe the periodicity and the existence of PST on some specific graphs.
基金Supported by National Natural Science Foundation of China under Grant Nos.11005099,60677044the Fundamental Research Funds for the Central Universities under Grant No.201013037
文摘We investigate the effect of phase shift on the perfect state transfer through two parallel one-dimensional ring-shaped spin chains. We find that the total success probability can be significantly enhanced by phase shift control when the communication channel consists of two odd chains. The average time to gain unit success probability is discussed, showing that a proper phase shift can be used to enhance the efficiency of state transmission.
基金Supported by the National Natural Science Foundation of China(Grant Nos.11601431,11871398,12071370,U1803263 and 12131013)the Natural Science Foundation of Shaanxi Province(Grant No.2020JM-099)the Natural Science Foundation of Qinghai Province(Grant No.2020-ZJ-920)。
文摘In this paper,we give some sufficient conditions for extended neighborhood coronas to have Laplacian perfect state transfer.We also give some conditions for extended neighborhood coronas to be periodic.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 90203018, 10474104, and 10447133, and the Knowledge Innovation Program （KIP） of the Chinese Academy of Sciences, the National Fundamental Research Program of China under Grant No. 2001CB309310
文摘The quantum state transmission through the medium of high-dimensional many-particle system （boson or spinless fermion） is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonian matches the symmetry of a fermion or boson system in a certain fashion, a perfect quantum state transfer can be implemented without any operation on the medium with pre-engineered nearest neighbor （NN）. We also study a simple but realistic near half-filled tight-bindlng fermion system wlth uniform NN hopping integral. We show that an arbitrary many-particle state near the fermi surface can be perfectly transferred to its translational counterpart.
文摘优异的光学吸收器一直具备着高品质因数和完美吸收的特性,然而,这类吸收器通常会受到传统表面等离子体共振带来的欧姆损耗,制约其在实际应用中的吸收性能.本文提出了一种基于法布里-珀罗腔的可调谐连续域束缚态(bound state in the continuum,BIC),通过调整模型的参数,可将BIC可以转变为准BIC,在连续谱中实现了100%的完美吸收.在本文中,采用干涉理论探究了影响完美吸收的因素,用耦合模理论和阻抗匹配理论对准BIC进行理论计算,采用电场和磁场理论解释了吸收器完美吸收的物理机制.与传统吸收器相比,该吸收器具有优异的结构参数鲁棒性和广泛的BIC调控范围.更重要的是,该吸收器具有出色的传感性能,其最大灵敏度可达34 nm/RIU,最大品质因数为9.5.最后,该吸收器还实现了双频的开光性能,其中双频开关的最大调制深度和最小插入损耗分别为99.4%和0.0004 dB.这些研究结果在光子学、光通信、传感器技术等领域具有重要意义.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61802002 and 61701004)the Natural Science Foundation of Anhui Province,China(Grant No.1708085MF162)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20171458)。
文摘Perfect state transfer(PST)has great significance due to its applications in quantum information processing and quantum computation.The main problem we study in this paper is to determine whether the two-fold Cayley tree,an extension of the Cayley tree,admits perfect state transfer between two roots using quantum walks.We show that PST can be achieved by means of the so-called nonrepeating quantum walk[Phys.Rev.A 89042332(2014)]within time steps that are the distance between the two roots;while both the continuous-time quantum walk and the typical discrete-time quantum walk with Grover coin approaches fail.Our results suggest that in some cases the dynamics of a discrete-time quantum walk may be much richer than that of the continuous-time quantum walk.
基金Sponsored by the National Science and Technology Major Special Project of China (Grant No.2011ZX03003-003-02)the Natural Science Foundation of China (Grant No. 60972070)+2 种基金the Natural Science Foundation of Chongqing (Grant No. CSTC2009BA2090)the Foundation of Chongqing Educational Committee ( Grant No. KJ100514)the Special Fund of Chongqing Key Laboratory
文摘A cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer (LL) is presented, in cooperative relay system over Nakagami-m fading channels with perfect and imperfect channel state information (CSI). In order to maximize spectral efficiency (SE) under delay and packet error rate (PER) performance constraints, a state transition model and an optimization framework with perfect CSI are presented. Then the framework is extended to cooperative relay system with imperfect CSI. The numerical results show that the scheme can achieve maximum SE while satisfying transmitting delay requirements. Compared with the imperfect CSI, the average PER with perfect CSI is much lower and the spectral efficiency is much higher.
