Improvement of the detection ability of quantum entanglement is one of the essential tasks in quantum computing and quantum information.Finite tight frames play a fundamental role in a wide variety of areas and,genera...Improvement of the detection ability of quantum entanglement is one of the essential tasks in quantum computing and quantum information.Finite tight frames play a fundamental role in a wide variety of areas and,generally,each application requires a specific class of frames and is closely related to quantum measurement.It is worth noting that a maximal set of complex equiangular vectors is closely related to a symmetric informationally complete measurement.Hence,our goal in this work is to propose a series of separability criteria assigned to a finite tight frame and some well-known inequalities in different quantum systems,respectively.In addition,some tighter criteria to detect entanglement for many-body quantum states are presented in arbitrary dimensions.Finally,the effectiveness of the proposed entanglement detection criteria is illustrated through some detailed examples.展开更多
A monitoring scheme must be so designed that several possible mod-els can be efficiently separated in the stage of analysis of deformation measure-ments.Based on the concept of separability developed by Chen and Chrza...A monitoring scheme must be so designed that several possible mod-els can be efficiently separated in the stage of analysis of deformation measure-ments.Based on the concept of separability developed by Chen and Chrzanowski,a methodology for the design of monitoring schemes has been developed by the au-thors.In the method a computer simulation technique is employed,into whichsome rules have been elaborated allowing minimal human intervention.In this pa-per the criterion is first presented and the design technique using the step one up-dating procedure is discussed.Finally,design of a simulated monitoring networkis made as a demonstrating example.展开更多
In this paper,we propose a new approach to tackle the separability problem for bipartite qudit mixed-states.This is based on the Majorana representation which allows to represent a N-spinors(qudit)as a symmetric state...In this paper,we propose a new approach to tackle the separability problem for bipartite qudit mixed-states.This is based on the Majorana representation which allows to represent a N-spinors(qudit)as a symmetric state of N spin-1/2.We also discuss how we can exploit such representation and the notion of the biseparability of multipartite qubit states in the sense to establish new criteria of the separability problem based on the PPT and concurrence.展开更多
We discuss separability of solutions to a Schr?dinger equation that describes a composite quantum system and give some kinds of Hamiltonians H(t) such that the solution to Schr?dinger equation induced by H(t) is separ...We discuss separability of solutions to a Schr?dinger equation that describes a composite quantum system and give some kinds of Hamiltonians H(t) such that the solution to Schr?dinger equation induced by H(t) is separable at any time provided that it is separable at t = 0. For example, we prove that if the Hamiltonian H is time-independent and equals to the product PA■PB of two projections on the subsystems KAand KB, respectively, then the state |ψ(t) of the composite system starting from a separable initial |ψ(0) = |ψA■|ψB is separable for all t ∈ [0, T] if and only if either |ψA is an eigenstate of PA, or |ψB is an eigenstate of PB.展开更多
The performances of a two-mode Gaussian state under paxametric amplification, symmetric amplitude damping and thermal noise axe studied. The time-dependent complex correlation matrix of the state in evolution is given...The performances of a two-mode Gaussian state under paxametric amplification, symmetric amplitude damping and thermal noise axe studied. The time-dependent complex correlation matrix of the state in evolution is given. The sepaxability of the final two-mode Gaussian state is examined under symmetric amplification and asymmetric amplification separately.展开更多
Highly symmetric quantum measurements,such as mutually unbiased measurements(MUMs)and general symmetric informationally complete positive-operator-valued measures(GSICPOVMs),play an important role in both foundational...Highly symmetric quantum measurements,such as mutually unbiased measurements(MUMs)and general symmetric informationally complete positive-operator-valued measures(GSICPOVMs),play an important role in both foundational and practical aspects of quantum information theory.Recently,a broad class of symmetric measurements were introduced[K Siudzińska,(2022)Phys.Rev.A 105,042209],which can be viewed as a common generalization of MUMs and GSIC-POVMs.In this work,the role of these symmetric measurements in entanglement detection is studied.More specifically,based on the correlation matrices defined via(informationally complete)symmetric measurements,a separability criterion for arbitrary dimensional bipartite systems is proposed.It is shown that the criterion is stronger than the method provided by Siudzińska,meanwhile,it can unify several popular separability criteria based on MUMs or GSIC-POVMs.Furthermore,using these(informationally complete)symmetric measurements,two efficient criteria are presented to detect the entanglement of tripartite quantum states.The detection power and advantages of these criteria are illustrated through several examples.展开更多
In this paper we present a necessary and sufficient condition of separability for multipartite pure states and variants of it. These conditions are very simple and calculable, and they do not require Schmidt decomposi...In this paper we present a necessary and sufficient condition of separability for multipartite pure states and variants of it. These conditions are very simple and calculable, and they do not require Schmidt decomposition （for two subsystems） or tracing out operations. We also give a necessary condition for a local unitary equivalence class for a bipartite system in terms of the determinant of the matrix of amplitudes.展开更多
Separability is an important problem in theory of quantum entanglement. By using the Bloch representation of quantum states in terms of the Heisenberg-Weyl observable basis, we present a new separability criterion for...Separability is an important problem in theory of quantum entanglement. By using the Bloch representation of quantum states in terms of the Heisenberg-Weyl observable basis, we present a new separability criterion for bipartite quantum systems. It is shown that this criterion can be better than the previous ones in detecting entanglement. The results are generalized to multipartite quantum states.展开更多
The valence state of C atoms and the structure of molecular orbitals of the (Buckminster)Fullerene C_(60)have been demonstrated. It has been shown that when a motion-coordinate system is adopted, in which the coordina...The valence state of C atoms and the structure of molecular orbitals of the (Buckminster)Fullerene C_(60)have been demonstrated. It has been shown that when a motion-coordinate system is adopted, in which the coordinate origin is at every C atom, the z axis is in the direction of the normal and the (x,y) axes are in the direction of tangents of C_(60)'s spherical surface, 240 valence atomic orbitals of C_(60) can be divided into two groups. All (P_x, P_y)atomic orbitals named as Pt ones and all the other P_z atomic orbitals named as p. ones, That is to say that if we name the molecular orbital linearly combined of P_t atomic orbitals as σ_t and the molecular orbital linearly combined of P_n atomic orbitals as π_n, the 240 valence molecular orbitals are of the property of σ_t-π_n separability. It has also been shown that the frontier and nearby frontier molecular orbitals are π_n ones, and therefore the essential physical and chemical properties of C_(60) are determined by its π_n molecular orbitals.展开更多
A sufficient and necessary criterion for separability of bipartite quantum states is presented. We construct a class of mixed states in 2 k quantum systems and in 3 k quantum systems, respectively and show that thes...A sufficient and necessary criterion for separability of bipartite quantum states is presented. We construct a class of mixed states in 2 k quantum systems and in 3 k quantum systems, respectively and show that these states are separable if and only if they are positive partial transpositions.展开更多
We show that the quantum world with non-local states and original statistics is statistically separable. According to relativistic dynamics, the super-luminal signal transmission is impossible. The present quantum the...We show that the quantum world with non-local states and original statistics is statistically separable. According to relativistic dynamics, the super-luminal signal transmission is impossible. The present quantum theory is therefore consistent with the relativity and the causality.展开更多
The conditional version of sandwiched Tsallis relative entropy (CSTRE) is employed to study the bipartite separability of one parameter family of N-qudit Werner-Popescu states in their 1:N-1 partition. For all N, the ...The conditional version of sandwiched Tsallis relative entropy (CSTRE) is employed to study the bipartite separability of one parameter family of N-qudit Werner-Popescu states in their 1:N-1 partition. For all N, the strongest limitation on bipartite separability is realized in the limit and is found to match exactly with the separability range obtained using an algebraic method which is both necessary and sufficient. The theoretical superiority of using CSTRE criterion to find the bipartite separability range over the one using Abe-Rajagopal (AR) q-conditional entropy is illustrated by comparing the convergence of the parameter x with respect to q, in the implicit plots of AR q-conditional entropy and CSTRE.展开更多
An algorithm is developed to calculate the entanglement of formation for bipartite quantum states to determine numerically the sufficient condition of separability. The algorithm is applied to two 3 × 3 positive ...An algorithm is developed to calculate the entanglement of formation for bipartite quantum states to determine numerically the sufficient condition of separability. The algorithm is applied to two 3 × 3 positive partial transpose states mixed with white noise. For these two noisy states, our numerical sufficient conditions of separability are not far from the best necessary conditions of separability.展开更多
Entanglement is an important resource for quantum information processing.We provide a new entanglement witness to detect the entanglement of an evolving W state.Our results show that the new entanglement witness match...Entanglement is an important resource for quantum information processing.We provide a new entanglement witness to detect the entanglement of an evolving W state.Our results show that the new entanglement witness matches the evolving W state better than other witnesses or methods.The new witness significantly improves the performance of entanglement detection for some three-qubit states.展开更多
We study the normal form of multipartite density matrices.It is shown that the correlation matrix(CM)separability criterion can be improved from the normal form we obtained under filtering transformations.Based on CMc...We study the normal form of multipartite density matrices.It is shown that the correlation matrix(CM)separability criterion can be improved from the normal form we obtained under filtering transformations.Based on CMcriterion the entanglement witness is further constructed in terms of local orthogonal observables for both bipartite andmultipartite systems.展开更多
In the present manuscript, we formulate and prove rigorously, necessary and sufficient conditions for all kinds of separation of variables that a solution of the irrotational Stokes equation may exhibit, in any orthog...In the present manuscript, we formulate and prove rigorously, necessary and sufficient conditions for all kinds of separation of variables that a solution of the irrotational Stokes equation may exhibit, in any orthogonal axisymmetric system, namely: simple separation and R-separation. These conditions may serve as a road map for obtaining the corresponding solution space of the irrotational Stokes equation, in any orthogonal axisymmetric coordinate system. Additionally, we investigate how the inversion of the coordinate system, with respect to a sphere, affects the type of separation. Specifically, we prove that if the irrotational Stokes equation separates variables in an axisymmetric coordinate system, then it R-separates variables in the corresponding inverted coordinate system. This is a quite useful outcome since it allows the derivation of solutions for a problem, from the knowledge of the solution of the same problem in the inverted geometry and vice-versa. Furthermore, as an illustration, we derive the eigenfunctions of the irrotational Stokes equation governing the flow past oblate spheroid particles and inverted oblate spheroidal particles.展开更多
Atmospheric turbulence distorts the complex wavefront of light in free-space optical communication systems,leading to bit errors and even communication interruptions.Recently,it is found that the non-separability of v...Atmospheric turbulence distorts the complex wavefront of light in free-space optical communication systems,leading to bit errors and even communication interruptions.Recently,it is found that the non-separability of vectorial structured light remains invariant when transmitting through atmospheric turbulence.This discovery offers a potential solution for turbulence-resilient communications—encoding based on the non-separability of vectorial structured light.To achieve such turbulence-resilient communications,efficient detection of the non-separability of vectorial structured light is essential,which acts as the receivers of such communication systems.So far,traditional non-separability detection schemes usually rely on bulky SLMs or DMDs,facing inherent trade-offs between single-shot capability and system compactness.In addition,the detection of mode-resolved non-separability contributions of vectorial superposition states has not yet been accomplished.Here,we propose and experimentally demonstrate a coherent detector to characterize the non-separability of vectorial structured light based on off-axis digital holography,which overcomes the limitations of traditional approaches by digitally decomposing spatial modes.Our approach may pave the way for turbulence-resilient optical communications based on non-separability coding methods and bring new insights into non-separability measurement.展开更多
In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar perce...In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.展开更多
The separability and the entanglement(that is,inseparability)of the composite quantum states play important roles in quantum information theory.Mathematically,a quantum state is a trace-class positive operator with tr...The separability and the entanglement(that is,inseparability)of the composite quantum states play important roles in quantum information theory.Mathematically,a quantum state is a trace-class positive operator with trace one acting on a complex separable Hilbert space.In this paper,in more general frame,the notion of separability for quantum states is generalized to bounded positive operators acting on tensor product of Hilbert spaces.However,not like the quantum state case,there are different kinds of separability for positive operators with different operator topologies.Four types of such separability are discussed;several criteria such as the finite rank entanglement witness criterion,the positive elementary operator criterion and PPT criterion to detect the separability of the positive operators are established;some methods to construct separable positive operators by operator matrices are provided.These may also make us to understand the separability and entanglement of quantum states better,and may be applied to find new separable quantum states.展开更多
基金supported by the Natural Science Foundation of Sichuan Province(Grant No.25QNJJ4066)。
文摘Improvement of the detection ability of quantum entanglement is one of the essential tasks in quantum computing and quantum information.Finite tight frames play a fundamental role in a wide variety of areas and,generally,each application requires a specific class of frames and is closely related to quantum measurement.It is worth noting that a maximal set of complex equiangular vectors is closely related to a symmetric informationally complete measurement.Hence,our goal in this work is to propose a series of separability criteria assigned to a finite tight frame and some well-known inequalities in different quantum systems,respectively.In addition,some tighter criteria to detect entanglement for many-body quantum states are presented in arbitrary dimensions.Finally,the effectiveness of the proposed entanglement detection criteria is illustrated through some detailed examples.
文摘A monitoring scheme must be so designed that several possible mod-els can be efficiently separated in the stage of analysis of deformation measure-ments.Based on the concept of separability developed by Chen and Chrzanowski,a methodology for the design of monitoring schemes has been developed by the au-thors.In the method a computer simulation technique is employed,into whichsome rules have been elaborated allowing minimal human intervention.In this pa-per the criterion is first presented and the design technique using the step one up-dating procedure is discussed.Finally,design of a simulated monitoring networkis made as a demonstrating example.
文摘In this paper,we propose a new approach to tackle the separability problem for bipartite qudit mixed-states.This is based on the Majorana representation which allows to represent a N-spinors(qudit)as a symmetric state of N spin-1/2.We also discuss how we can exploit such representation and the notion of the biseparability of multipartite qubit states in the sense to establish new criteria of the separability problem based on the PPT and concurrence.
基金Supported by the NNSF of China under Grant Nos.11371012,11171197the IFGP of Shaanxi Normal University(2013CXB012)+2 种基金the FRF for the Central Universities(GK201404001,GK201301007,GK201402005)China PSF(2014M552405)the NSRP of Shaanxi Province(2014JQ1010)
文摘We discuss separability of solutions to a Schr?dinger equation that describes a composite quantum system and give some kinds of Hamiltonians H(t) such that the solution to Schr?dinger equation induced by H(t) is separable at any time provided that it is separable at t = 0. For example, we prove that if the Hamiltonian H is time-independent and equals to the product PA■PB of two projections on the subsystems KAand KB, respectively, then the state |ψ(t) of the composite system starting from a separable initial |ψ(0) = |ψA■|ψB is separable for all t ∈ [0, T] if and only if either |ψA is an eigenstate of PA, or |ψB is an eigenstate of PB.
基金Project supported by the National Natural Science Foundation of China （Grant No 10575092）, the Zhejiang Province Natural Science Foundation （Grant No RC104265） and General Administration of Quality Supervision,Inspection and Quarantine of China . （Grant No 2004QK38）.
文摘The performances of a two-mode Gaussian state under paxametric amplification, symmetric amplitude damping and thermal noise axe studied. The time-dependent complex correlation matrix of the state in evolution is given. The sepaxability of the final two-mode Gaussian state is examined under symmetric amplification and asymmetric amplification separately.
基金supported by the National Key R&D Program of China,Grant No.2020YFA0712700the National Natural Science Foundation of China,Grant Nos.11875317 and 61833010
文摘Highly symmetric quantum measurements,such as mutually unbiased measurements(MUMs)and general symmetric informationally complete positive-operator-valued measures(GSICPOVMs),play an important role in both foundational and practical aspects of quantum information theory.Recently,a broad class of symmetric measurements were introduced[K Siudzińska,(2022)Phys.Rev.A 105,042209],which can be viewed as a common generalization of MUMs and GSIC-POVMs.In this work,the role of these symmetric measurements in entanglement detection is studied.More specifically,based on the correlation matrices defined via(informationally complete)symmetric measurements,a separability criterion for arbitrary dimensional bipartite systems is proposed.It is shown that the criterion is stronger than the method provided by Siudzińska,meanwhile,it can unify several popular separability criteria based on MUMs or GSIC-POVMs.Furthermore,using these(informationally complete)symmetric measurements,two efficient criteria are presented to detect the entanglement of tripartite quantum states.The detection power and advantages of these criteria are illustrated through several examples.
基金The project supported by National Natural Science Foundation of China under Grant No.60433050the Fundamental Research Fund of Tsinghua University under Grant No.JC2003043partially by the State Key Lab.of Intelligence Technology and System
文摘In this paper we present a necessary and sufficient condition of separability for multipartite pure states and variants of it. These conditions are very simple and calculable, and they do not require Schmidt decomposition （for two subsystems） or tracing out operations. We also give a necessary condition for a local unitary equivalence class for a bipartite system in terms of the determinant of the matrix of amplitudes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11501153,11661031,and 11675113)the National Natural Science Foundation of Hainan Province,China(Grant No.20161006)
文摘Separability is an important problem in theory of quantum entanglement. By using the Bloch representation of quantum states in terms of the Heisenberg-Weyl observable basis, we present a new separability criterion for bipartite quantum systems. It is shown that this criterion can be better than the previous ones in detecting entanglement. The results are generalized to multipartite quantum states.
文摘The valence state of C atoms and the structure of molecular orbitals of the (Buckminster)Fullerene C_(60)have been demonstrated. It has been shown that when a motion-coordinate system is adopted, in which the coordinate origin is at every C atom, the z axis is in the direction of the normal and the (x,y) axes are in the direction of tangents of C_(60)'s spherical surface, 240 valence atomic orbitals of C_(60) can be divided into two groups. All (P_x, P_y)atomic orbitals named as Pt ones and all the other P_z atomic orbitals named as p. ones, That is to say that if we name the molecular orbital linearly combined of P_t atomic orbitals as σ_t and the molecular orbital linearly combined of P_n atomic orbitals as π_n, the 240 valence molecular orbitals are of the property of σ_t-π_n separability. It has also been shown that the frontier and nearby frontier molecular orbitals are π_n ones, and therefore the essential physical and chemical properties of C_(60) are determined by its π_n molecular orbitals.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11101017 and 11275131)Beijing Natural Science Foundation Program,and the Scientific Research Key Program of Beijing Municipal Commission of Education(Grant No.KZ201210028032)the Importation and Developmentof High-Caliber Talents Project of Beijing Municipal Institutions(Grant No.CIT&TCD201404067)
文摘A sufficient and necessary criterion for separability of bipartite quantum states is presented. We construct a class of mixed states in 2 k quantum systems and in 3 k quantum systems, respectively and show that these states are separable if and only if they are positive partial transpositions.
基金The project supported by National Natural Science Foundation of China under Grant No. 10305001
文摘We show that the quantum world with non-local states and original statistics is statistically separable. According to relativistic dynamics, the super-luminal signal transmission is impossible. The present quantum theory is therefore consistent with the relativity and the causality.
文摘The conditional version of sandwiched Tsallis relative entropy (CSTRE) is employed to study the bipartite separability of one parameter family of N-qudit Werner-Popescu states in their 1:N-1 partition. For all N, the strongest limitation on bipartite separability is realized in the limit and is found to match exactly with the separability range obtained using an algebraic method which is both necessary and sufficient. The theoretical superiority of using CSTRE criterion to find the bipartite separability range over the one using Abe-Rajagopal (AR) q-conditional entropy is illustrated by comparing the convergence of the parameter x with respect to q, in the implicit plots of AR q-conditional entropy and CSTRE.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11375152 and 60972071the Key Laboratory of New Network Standards and Technologies of Zhejiang Province under Grant No 2013E10012
文摘An algorithm is developed to calculate the entanglement of formation for bipartite quantum states to determine numerically the sufficient condition of separability. The algorithm is applied to two 3 × 3 positive partial transpose states mixed with white noise. For these two noisy states, our numerical sufficient conditions of separability are not far from the best necessary conditions of separability.
基金Support from the National Natural Science Foundation of China(Grant No:61871347)。
文摘Entanglement is an important resource for quantum information processing.We provide a new entanglement witness to detect the entanglement of an evolving W state.Our results show that the new entanglement witness matches the evolving W state better than other witnesses or methods.The new witness significantly improves the performance of entanglement detection for some three-qubit states.
基金National Natural Science Foundation of China under Grant Nos.10675086 and KM200510028022National Key Basic Research Program of China under Grant No.2004CB318000
文摘We study the normal form of multipartite density matrices.It is shown that the correlation matrix(CM)separability criterion can be improved from the normal form we obtained under filtering transformations.Based on CMcriterion the entanglement witness is further constructed in terms of local orthogonal observables for both bipartite andmultipartite systems.
文摘In the present manuscript, we formulate and prove rigorously, necessary and sufficient conditions for all kinds of separation of variables that a solution of the irrotational Stokes equation may exhibit, in any orthogonal axisymmetric system, namely: simple separation and R-separation. These conditions may serve as a road map for obtaining the corresponding solution space of the irrotational Stokes equation, in any orthogonal axisymmetric coordinate system. Additionally, we investigate how the inversion of the coordinate system, with respect to a sphere, affects the type of separation. Specifically, we prove that if the irrotational Stokes equation separates variables in an axisymmetric coordinate system, then it R-separates variables in the corresponding inverted coordinate system. This is a quite useful outcome since it allows the derivation of solutions for a problem, from the knowledge of the solution of the same problem in the inverted geometry and vice-versa. Furthermore, as an illustration, we derive the eigenfunctions of the irrotational Stokes equation governing the flow past oblate spheroid particles and inverted oblate spheroidal particles.
基金supported by the National Key R&D Program of China(2025YFE0102200)National Natural Science Foundation of China(62405233,62125503,62261160388)+4 种基金Fundamental Research Funds for the Central Universities(XJSJ24030)Natural Science Foundation of Hubei Province of China(2023AFA028)Hubei Optical Fundamental Research Center(HBO2025TQ004)the Opening Project of Henan Province Engineering Technology Research Center for Photoelectric Detection and Sensing Integration,Henan Polytechnic University(KF202504)Yize Liang thanks UPOLabs for providing the SLM(HDSLM80R-PLUS).
文摘Atmospheric turbulence distorts the complex wavefront of light in free-space optical communication systems,leading to bit errors and even communication interruptions.Recently,it is found that the non-separability of vectorial structured light remains invariant when transmitting through atmospheric turbulence.This discovery offers a potential solution for turbulence-resilient communications—encoding based on the non-separability of vectorial structured light.To achieve such turbulence-resilient communications,efficient detection of the non-separability of vectorial structured light is essential,which acts as the receivers of such communication systems.So far,traditional non-separability detection schemes usually rely on bulky SLMs or DMDs,facing inherent trade-offs between single-shot capability and system compactness.In addition,the detection of mode-resolved non-separability contributions of vectorial superposition states has not yet been accomplished.Here,we propose and experimentally demonstrate a coherent detector to characterize the non-separability of vectorial structured light based on off-axis digital holography,which overcomes the limitations of traditional approaches by digitally decomposing spatial modes.Our approach may pave the way for turbulence-resilient optical communications based on non-separability coding methods and bring new insights into non-separability measurement.
基金Supported by the Doctoral Research Start-up Project of Yuncheng University(YQ-2023067)Project of Shanxi Natural Science Foundation(202303021211189)+1 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provinces(20220036)Shanxi ProvinceIntelligent Optoelectronic Sensing Application Technology Innovation Center and Shanxi Province Optoelectronic Information Science and TechnologyLaboratory,Yuncheng University.
文摘In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.
基金Supported by National Natural Science Foundation of China(Grant No.11171249)。
文摘The separability and the entanglement(that is,inseparability)of the composite quantum states play important roles in quantum information theory.Mathematically,a quantum state is a trace-class positive operator with trace one acting on a complex separable Hilbert space.In this paper,in more general frame,the notion of separability for quantum states is generalized to bounded positive operators acting on tensor product of Hilbert spaces.However,not like the quantum state case,there are different kinds of separability for positive operators with different operator topologies.Four types of such separability are discussed;several criteria such as the finite rank entanglement witness criterion,the positive elementary operator criterion and PPT criterion to detect the separability of the positive operators are established;some methods to construct separable positive operators by operator matrices are provided.These may also make us to understand the separability and entanglement of quantum states better,and may be applied to find new separable quantum states.
