Unravelling the source of quantum computing power has been a major goal in the field of quantum information science.In recent years,the quantum resource theory(QRT)has been established to characterize various quantum ...Unravelling the source of quantum computing power has been a major goal in the field of quantum information science.In recent years,the quantum resource theory(QRT)has been established to characterize various quantum resources,yet their roles in quantum computing tasks still require investigation.The so-called universal quantum computing model(UQCM),e.g.the circuit model,has been the main framework to guide the design of quantum algorithms,creation of real quantum computers etc.In this work,we combine the study of UQCM together with QRT.We find,on one hand,using QRT can provide a resource-theoretic characterization of a UQCM,the relation among models and inspire new ones,and on the other hand,using UQCM offers a framework to apply resources,study relation among these resources and classify them.We develop the theory of universal resources in the setting of UQCM,and find a rich spectrum of UQCMs and the corresponding universal resources.Depending on a hierarchical structure of resource theories,we find models can be classified into families.In this work,we study three natural families of UQCMs in detail:the amplitude family,the quasi-probability family,and the Hamiltonian family.They include some well known models,like the measurement-based model and adiabatic model,and also inspire new models such as the contextual model that we introduce.Each family contains at least a triplet of models,and such a succinct structure of families of UQCMs offers a unifying picture to investigate resources and design models.It also provides a rigorous framework to resolve puzzles,such as the role of entanglement versus interference,and unravel resource-theoretic features of quantum algorithms.展开更多
The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD h...The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.展开更多
We develop universal quantum computing models that form a family of quantum von Neumann architectures,with modular units of memory,control,CPU,and internet,besides input and output.This family contains three generatio...We develop universal quantum computing models that form a family of quantum von Neumann architectures,with modular units of memory,control,CPU,and internet,besides input and output.This family contains three generations characterized by dynamical quantum resource theory,and it also circumvents no-go theorems on quantum programming and control.Besides universality,such a family satisfies other desirable engineering requirements on system and algorithm design,such as modularity and programmability,hence serves as a unique approach to building universal quantum computers.展开更多
We define the resource non-increasing(RNI)framework to study the dynamical resource theory.With this definition,we propose several potential quantification candidates under various free operation sets.For explicit dem...We define the resource non-increasing(RNI)framework to study the dynamical resource theory.With this definition,we propose several potential quantification candidates under various free operation sets.For explicit demonstrations,we quantify the quantum dynamical coherence in the scenarios with and without post-selective measurements.Correspondingly,we show that the maximally incoherent operations(MIO)and the incoherent operations(IO)in the static coherence resource theory are free in the sense of dynamical coherence.We also provide operational meanings for the measures by the quantum discrimination tasks.Moreover,for the dynamical total coherence,we also present convenient measures and give the analytic calculation for the amplitude damping channel.展开更多
Complex numbers play a pivotal role in both mathematics and physics,particularly in quantum mechanics,and are extensively utilized to depict the behavior of microscopic particles.Recognizing the significance of comple...Complex numbers play a pivotal role in both mathematics and physics,particularly in quantum mechanics,and are extensively utilized to depict the behavior of microscopic particles.Recognizing the significance of complex numbers,a framework of imaginarity resource theory has recently been established.In this work,we propose two types of imaginarity monotones induced by the unified(α,β)-relative entropy and investigate their properties.Moreover,we give explicit examples to illustrate our results.展开更多
Determining the minimal distance between the target state and the convex combination of given states is a fundamental problem in quantum resource theory,offering critical guidance for experimental implementations.In t...Determining the minimal distance between the target state and the convex combination of given states is a fundamental problem in quantum resource theory,offering critical guidance for experimental implementations.In this paper,we embark on an in-depth exploration of the use of a quantum state prepared by the convex combination of given qubit states to optimally approximate the l_(1)-norm of coherence of the target quantum state,striving to make the prepared state and the target state as similar as possible.Here,we present the analytical solution for the optimal distance for any N given quantum states.We find that the optimal approximation problem for any N>4 quantum states can be transformed into an optimal approximation problem for no more than four quantum states,which not only significantly streamlines the problem but also proves advantageous for laboratories in terms of material conservation.Ultimately,a one-to-one comparison between the analytical and numerical solutions verifies the effectiveness of our approach.展开更多
The Kirkwood-Dirac(KD)distribution is a vital framework in quantum state characterization,which reveals nonclassical correlations through phase-space representations.In this work,we introduce trace-norm-based measures...The Kirkwood-Dirac(KD)distribution is a vital framework in quantum state characterization,which reveals nonclassical correlations through phase-space representations.In this work,we introduce trace-norm-based measures to assess the KD-nonclassicality of quantum states and derive the corresponding trade-off relations for qubit and qutrit systems.For a bipartite state shared by Alice and Bob and a set of measurements applied by Alice,the maximum value of the totally averaged quantum resource of Bob’s states is introduced with respect to a quantum resource quantifier.When the maximum value exceeds the upper bound in a trade-off relation,the bipartite state is said to exhibit nonlocal advantages of quantum resource(NAQR).We prove that a state exhibiting NAQR,such as nonlocal advantages of KD-nonclassicality(NAKDNC),is steerable from Alice to Bob.We demonstrate that NAKDNC of Werner states exhibit much more quantum steering than quantum coherence and quantum imaginarity do and also explore NAKDNC of the two-qutrit isotropic states.These findings emerge KD-nonclassicality as an independent nonclassical resource with operational relevance in quantum information protocols.展开更多
An optical frequency comb comprises a cluster of equally spaced,phase-locked spectral lines.Replacing these classical components with correlated quantum light gives rise to cluster quantum frequency combs,providing ab...An optical frequency comb comprises a cluster of equally spaced,phase-locked spectral lines.Replacing these classical components with correlated quantum light gives rise to cluster quantum frequency combs,providing abundant quantum resources for measurement-based quantum computation,and multi-user quantum networks.We propose and generate cluster quantum microcombs within an on-chip optical microresonator driven by multi-frequency lasers.Through resonantly enhanced four-wave mixing processes,continuous-variable cluster states with 60 qumodes are deterministically created.The graph structures can be programmed into one-and two-dimensional lattices by adjusting the configurations of the pump lines,which are confirmed inseparable based on the measured covariance matrices.Our work demonstrates the largest-scale cluster states with unprecedented raw squeezing levels from a photonic chip,offering a compact and scalable platform for computational and communicational tasks with quantum advantages.展开更多
We establish entanglement monotones in terms of an operational approach,which is closely connected with the state conversion from pure states to the objective state by the local operations and classical communications...We establish entanglement monotones in terms of an operational approach,which is closely connected with the state conversion from pure states to the objective state by the local operations and classical communications.It is shown that any good entanglement quantifier defined on pure states can induce an entanglement monotone for all density matrices.Particularly,we show that our entanglement monotone is the maximal one among all those having the same form for pure states.In some special cases,our proposed entanglement monotones turn to be equivalent to the convex roof construction,which hence gain an operational meaning.Some examples are given to demonstrate different cases.展开更多
A fully connected quantum network with a wavelength division multiplexing architecture plays an increasingly pivotal role in quantum information technology.With such architecture,an entanglement-based network has been...A fully connected quantum network with a wavelength division multiplexing architecture plays an increasingly pivotal role in quantum information technology.With such architecture,an entanglement-based network has been demonstrated in which an entangled photon-pair source distributes quantum entanglement resources to many users.Despite these remarkable advances,the scalability of the architecture could be constrained by the finite spectrum resource,where&(N2)wavelength channels are needed to connect N users,thus impeding further progress in real-world scenarios.Here,we propose a scheme for the wavelength division multiplexing entanglement-based network using a state-multiplexing quantum light source.With a dual-pump configuration,the feasibility of our approach is demonstrated by generating state-multiplexing photon pairs at multiple wavelength channels with a silicon nitride microring resonator chip.In our demonstration,we establish a fully connected graph between four users with six wavelength channels—saving half of which without sacrificing functionality and performance of the secure communication.A total asymptotic secure key rate of 1946.9 bps is obtained by performing the BBM92 protocol with the distributed state.The network topology of our method has great potential for developing a scalable quantum network with significantly minimized infrastructure requirements.展开更多
Quantum key distribution with different frequency codes is demonstrated with a reconfigurable entanglement distribution network,which is essential for scalable and resource-efficient quantum communications.
From the perspective of resource-theoretic approach,this study explores the quantification of imaginary in quantum physics.We propose a well defined measure of imaginarity,the geometric-like measure of imaginarity.Com...From the perspective of resource-theoretic approach,this study explores the quantification of imaginary in quantum physics.We propose a well defined measure of imaginarity,the geometric-like measure of imaginarity.Compared with the usual geometric imaginarity measure,this geometric-like measure of imaginarity exhibits smaller decay difference under quantum noisy channels and higher stability.As applications,we show that both the optimal probability of state transformations from a pure state to an arbitrary mixed state via real operations,and the maximal probability of stochastic-approximate state transformations from a pure state to an arbitrary mixed state via real operations with a given fidelity f,are given by the geometric-like measure of imaginarity.展开更多
基金funded by the National Natural Science Foundation of China under Grants Nos.12047503 and 12105343.
文摘Unravelling the source of quantum computing power has been a major goal in the field of quantum information science.In recent years,the quantum resource theory(QRT)has been established to characterize various quantum resources,yet their roles in quantum computing tasks still require investigation.The so-called universal quantum computing model(UQCM),e.g.the circuit model,has been the main framework to guide the design of quantum algorithms,creation of real quantum computers etc.In this work,we combine the study of UQCM together with QRT.We find,on one hand,using QRT can provide a resource-theoretic characterization of a UQCM,the relation among models and inspire new ones,and on the other hand,using UQCM offers a framework to apply resources,study relation among these resources and classify them.We develop the theory of universal resources in the setting of UQCM,and find a rich spectrum of UQCMs and the corresponding universal resources.Depending on a hierarchical structure of resource theories,we find models can be classified into families.In this work,we study three natural families of UQCMs in detail:the amplitude family,the quasi-probability family,and the Hamiltonian family.They include some well known models,like the measurement-based model and adiabatic model,and also inspire new models such as the contextual model that we introduce.Each family contains at least a triplet of models,and such a succinct structure of families of UQCMs offers a unifying picture to investigate resources and design models.It also provides a rigorous framework to resolve puzzles,such as the role of entanglement versus interference,and unravel resource-theoretic features of quantum algorithms.
基金Supported by the National Basic Research Program of China under Grant No 2013CB338002the National Natural Science Foundation of China under Grant Nos 11304397 and 61505261
文摘The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12047503 and 12105343)。
文摘We develop universal quantum computing models that form a family of quantum von Neumann architectures,with modular units of memory,control,CPU,and internet,besides input and output.This family contains three generations characterized by dynamical quantum resource theory,and it also circumvents no-go theorems on quantum programming and control.Besides universality,such a family satisfies other desirable engineering requirements on system and algorithm design,such as modularity and programmability,hence serves as a unique approach to building universal quantum computers.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175029,11775040,and12011530014)。
文摘We define the resource non-increasing(RNI)framework to study the dynamical resource theory.With this definition,we propose several potential quantification candidates under various free operation sets.For explicit demonstrations,we quantify the quantum dynamical coherence in the scenarios with and without post-selective measurements.Correspondingly,we show that the maximally incoherent operations(MIO)and the incoherent operations(IO)in the static coherence resource theory are free in the sense of dynamical coherence.We also provide operational meanings for the measures by the quantum discrimination tasks.Moreover,for the dynamical total coherence,we also present convenient measures and give the analytic calculation for the amplitude damping channel.
基金supported by National Natural Science Foundation of China(Grant No.12161056)Natural Science Foundation of Jiangxi Province(Grant No.20232ACB211003)。
文摘Complex numbers play a pivotal role in both mathematics and physics,particularly in quantum mechanics,and are extensively utilized to depict the behavior of microscopic particles.Recognizing the significance of complex numbers,a framework of imaginarity resource theory has recently been established.In this work,we propose two types of imaginarity monotones induced by the unified(α,β)-relative entropy and investigate their properties.Moreover,we give explicit examples to illustrate our results.
基金supported by the Fundamental Research Projects of Shanxi Province(Grant No.202203021222225)the National Natural Science Foundation of China(Grant Nos.12175029,12011530014,and 11775040)the Key Research and Development Project of Liaoning Province(Grant No.2020JH2/10500003).
文摘Determining the minimal distance between the target state and the convex combination of given states is a fundamental problem in quantum resource theory,offering critical guidance for experimental implementations.In this paper,we embark on an in-depth exploration of the use of a quantum state prepared by the convex combination of given qubit states to optimally approximate the l_(1)-norm of coherence of the target quantum state,striving to make the prepared state and the target state as similar as possible.Here,we present the analytical solution for the optimal distance for any N given quantum states.We find that the optimal approximation problem for any N>4 quantum states can be transformed into an optimal approximation problem for no more than four quantum states,which not only significantly streamlines the problem but also proves advantageous for laboratories in terms of material conservation.Ultimately,a one-to-one comparison between the analytical and numerical solutions verifies the effectiveness of our approach.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12071179, 12271325, 12371132, 12075159, and 12171044)the Fundamental Research Funds for the Central Universities(Grant No. GK202501008)the specific research fund of the Innovation Platform for Academicians of Hainan Province
文摘The Kirkwood-Dirac(KD)distribution is a vital framework in quantum state characterization,which reveals nonclassical correlations through phase-space representations.In this work,we introduce trace-norm-based measures to assess the KD-nonclassicality of quantum states and derive the corresponding trade-off relations for qubit and qutrit systems.For a bipartite state shared by Alice and Bob and a set of measurements applied by Alice,the maximum value of the totally averaged quantum resource of Bob’s states is introduced with respect to a quantum resource quantifier.When the maximum value exceeds the upper bound in a trade-off relation,the bipartite state is said to exhibit nonlocal advantages of quantum resource(NAQR).We prove that a state exhibiting NAQR,such as nonlocal advantages of KD-nonclassicality(NAKDNC),is steerable from Alice to Bob.We demonstrate that NAKDNC of Werner states exhibit much more quantum steering than quantum coherence and quantum imaginarity do and also explore NAKDNC of the two-qutrit isotropic states.These findings emerge KD-nonclassicality as an independent nonclassical resource with operational relevance in quantum information protocols.
基金supported by the National Key R&D Plan of China(Grant No.2021ZD0301500)Beijing Natural Science Foundation(Z210004,Z240007)+2 种基金National Natural Science Foundation of China(92150108,62222515,12125402,12174438)the High-performance Computing Platform of Peking Universitysupported by the Micro/nano Fabrication Laboratory of Synergetic Extreme Condition User Facility(SECUF).
文摘An optical frequency comb comprises a cluster of equally spaced,phase-locked spectral lines.Replacing these classical components with correlated quantum light gives rise to cluster quantum frequency combs,providing abundant quantum resources for measurement-based quantum computation,and multi-user quantum networks.We propose and generate cluster quantum microcombs within an on-chip optical microresonator driven by multi-frequency lasers.Through resonantly enhanced four-wave mixing processes,continuous-variable cluster states with 60 qumodes are deterministically created.The graph structures can be programmed into one-and two-dimensional lattices by adjusting the configurations of the pump lines,which are confirmed inseparable based on the measured covariance matrices.Our work demonstrates the largest-scale cluster states with unprecedented raw squeezing levels from a photonic chip,offering a compact and scalable platform for computational and communicational tasks with quantum advantages.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11775040,12011530014 and 11375036)the Fundamental Research Funds for the Central Universities.China(Grant No.DUT20LAB203)。
文摘We establish entanglement monotones in terms of an operational approach,which is closely connected with the state conversion from pure states to the objective state by the local operations and classical communications.It is shown that any good entanglement quantifier defined on pure states can induce an entanglement monotone for all density matrices.Particularly,we show that our entanglement monotone is the maximal one among all those having the same form for pure states.In some special cases,our proposed entanglement monotones turn to be equivalent to the convex roof construction,which hence gain an operational meaning.Some examples are given to demonstrate different cases.
基金supported by Sichuan Science and Technology Program(Nos.2022YFSY0061,2022YFSY0062,2022YFSY0063,2023YFSY0062,2023YFSY0058,2023NSFSC0048)the National Natural Science Foundation of China(Nos.62475039,62405046,92365106,62105371)Innovation Program for Quantum Science and Technology(No.2021ZD0300701).
文摘A fully connected quantum network with a wavelength division multiplexing architecture plays an increasingly pivotal role in quantum information technology.With such architecture,an entanglement-based network has been demonstrated in which an entangled photon-pair source distributes quantum entanglement resources to many users.Despite these remarkable advances,the scalability of the architecture could be constrained by the finite spectrum resource,where&(N2)wavelength channels are needed to connect N users,thus impeding further progress in real-world scenarios.Here,we propose a scheme for the wavelength division multiplexing entanglement-based network using a state-multiplexing quantum light source.With a dual-pump configuration,the feasibility of our approach is demonstrated by generating state-multiplexing photon pairs at multiple wavelength channels with a silicon nitride microring resonator chip.In our demonstration,we establish a fully connected graph between four users with six wavelength channels—saving half of which without sacrificing functionality and performance of the secure communication.A total asymptotic secure key rate of 1946.9 bps is obtained by performing the BBM92 protocol with the distributed state.The network topology of our method has great potential for developing a scalable quantum network with significantly minimized infrastructure requirements.
文摘Quantum key distribution with different frequency codes is demonstrated with a reconfigurable entanglement distribution network,which is essential for scalable and resource-efficient quantum communications.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075159,12171044,and 12175147)the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province。
文摘From the perspective of resource-theoretic approach,this study explores the quantification of imaginary in quantum physics.We propose a well defined measure of imaginarity,the geometric-like measure of imaginarity.Compared with the usual geometric imaginarity measure,this geometric-like measure of imaginarity exhibits smaller decay difference under quantum noisy channels and higher stability.As applications,we show that both the optimal probability of state transformations from a pure state to an arbitrary mixed state via real operations,and the maximal probability of stochastic-approximate state transformations from a pure state to an arbitrary mixed state via real operations with a given fidelity f,are given by the geometric-like measure of imaginarity.
