Quantum coherence is a fundamental feature of quantum physics and plays a significant role in quantum information processing.By generalizing the resource theory of coherence from von Neumann measurements to positive o...Quantum coherence is a fundamental feature of quantum physics and plays a significant role in quantum information processing.By generalizing the resource theory of coherence from von Neumann measurements to positive operatorvalued measures(POVMs),POVM-based coherence measures have been proposed with respect to the relative entropy of coherence,the l_(1) norm of coherence,the robustness of coherence and the Tsallis relative entropy of coherence.We derive analytically the lower and upper bounds on these POVM-based coherence of an arbitrary given superposed pure state in terms of the POVM-based coherence of the states in superposition.Our results can be used to estimate range of quantum coherence of superposed states.Detailed examples are presented to verify our analytical bounds.展开更多
Quantum entanglement plays essential roles in quantum information processing.The monogamy and polygamy relations characterize the entanglement distributions in the multipartite systems.We present a class of monogamy i...Quantum entanglement plays essential roles in quantum information processing.The monogamy and polygamy relations characterize the entanglement distributions in the multipartite systems.We present a class of monogamy inequalities related to theµ-th power of the entanglement measure based on Renyi-αentropy,as well as polygamy relations in terms of theµ-th power of Renyi-αentanglement of assistance.These monogamy and polygamy relations are shown to be tighter than the existing ones.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
We investigate the monogamy and polygamy inequalities of arbitrary multipartite quantum states,and provide new classes of monogamy and polygamy inequalities of multiqubit entanglement in terms o f concurrence,entangle...We investigate the monogamy and polygamy inequalities of arbitrary multipartite quantum states,and provide new classes of monogamy and polygamy inequalities of multiqubit entanglement in terms o f concurrence,entanglement of formation,negativity,and Tsallis-q entanglement,respectively.We show that these new monogamy and polygamy inequality relations are tighter than the existing ones with detailed examples.展开更多
We establish tighter uncertainty relations for arbitrary finite observables via(α,β,γ)weighted Wigner–Yanase–Dyson((α,β,γ)WWYD)skew information.The results are also applicable to the(α,γ)weighted Wigner–Yan...We establish tighter uncertainty relations for arbitrary finite observables via(α,β,γ)weighted Wigner–Yanase–Dyson((α,β,γ)WWYD)skew information.The results are also applicable to the(α,γ)weighted Wigner–Yanase–Dyson((α,γ)WWYD)skew information and the weighted Wigner–Yanase–Dyson(WWYD)skew information.We also present tighter lower bounds for quantum channels and unitary channels via(α,β,γ)modified weighted Wigner–Yanase–Dyson((α,β,γ)MWWYD)skew information.Detailed examples are provided to illustrate the tightness of our uncertainty relations.展开更多
Quantum uncertainty relations constrain the precision of measurements across multiple non-commuting quantum mechanical observables.Here,we introduce the concept of optimal observable sets and define the tightest uncer...Quantum uncertainty relations constrain the precision of measurements across multiple non-commuting quantum mechanical observables.Here,we introduce the concept of optimal observable sets and define the tightest uncertainty constants to accurately describe these measurement uncertainties.For any quantum state,we establish optimal sets of three observables for both product and summation forms of uncertainty relations,and analytically derive the corresponding tightest uncertainty constants.We demonstrate that the optimality of these sets remains consistent regardless of the uncertainty relation form.Furthermore,the existence of the tightest constants excludes the validity of standard real quantum mechanics,underscoring the essential role of complex numbers in this field.Additionally,our findings resolve the conjecture posed in[Phys.Rev.Lett.118,180402(2017)],offering novel insights and potential applications in understanding preparation uncertainties.展开更多
The Bell nonlocality is closely related to the foundations of quantum physics and has significant applications to security questions in quantum key distributions.In recent years,the sharing ability of the Bell nonloca...The Bell nonlocality is closely related to the foundations of quantum physics and has significant applications to security questions in quantum key distributions.In recent years,the sharing ability of the Bell nonlocality has been extensively studied.The nonlocality of quantum network states is more complex.We first discuss the sharing ability of the simplest bilocality under unilateral or bilateral POVM measurements,and show that the nonlocality sharing ability of network quantum states under unilateral measurements is similar to the Bell nonlocality sharing ability,but different under bilateral measurements.For the star network scenarios,we present for the first time comprehensive results on the nonlocality sharing properties of quantum network states,for which the quantum nonlocality of the network quantum states has a stronger sharing ability than the Bell nonlocality.展开更多
We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are cou...We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are coupled to respective microwave cavities in resonant way,and the SC qubit is placed at the center of the cavities,which interacts with the cavities simultaneously.By exchanging the virtual photon,the cavities can indirectly interact in the far-detuning regime.Detailed protocols are presented to establish entanglement for two,three and arbitrary N magnons with reasonable fidelities.展开更多
Quantum state discrimination is an important part of quantum information processing.We investigate the discrimination of coherent states through a Jaynes-Cummings(JC)model interaction between the field and the ancilla...Quantum state discrimination is an important part of quantum information processing.We investigate the discrimination of coherent states through a Jaynes-Cummings(JC)model interaction between the field and the ancilla without rotation wave approximation(RWA).We show that the minimum failure probability can be reduced as RWA is eliminated from the JC model and the non-RWA terms accompanied by the quantum effects of fields(e.g.the virtualphoton process in the JC model without RWA)can enhance the state discrimination.The JC model without RWA for unambiguous state discrimination is superior to ambiguous state discrimination,particularly when the number of sequential measurements increases.Unambiguous state discrimination implemented via the non-RWA JC model is beneficial to saving resource costs.展开更多
Quantum coherence plays a central role in Grover’s search algorithm.We study the Tsallis relative a entropy of coherence dynamics of the evolved state in Grover’s search algorithm.We prove that the Tsallis relative ...Quantum coherence plays a central role in Grover’s search algorithm.We study the Tsallis relative a entropy of coherence dynamics of the evolved state in Grover’s search algorithm.We prove that the Tsallis relative a entropy of coherence decreases with the increase of the success probability,and derive the complementarity relations between the coherence and the success probability.We show that the operator coherence of the first H■relies on the size of the database N,the success probability and the target states.Moreover,we illustrate the relationships between coherence and entanglement of the superposition state of targets,as well as the production and deletion of coherence in Grover iterations.展开更多
Monogamy and polygamy relations characterize the distributions of entanglement in multipartite systems.We provide classes of monogamy and polygamy inequalities of multiqubit entanglement in terms of concurrence, entan...Monogamy and polygamy relations characterize the distributions of entanglement in multipartite systems.We provide classes of monogamy and polygamy inequalities of multiqubit entanglement in terms of concurrence, entanglement of formation, negativity, Tsallis-q entanglement, and Rényi-α entanglement, respectively. We show that these inequalities are tighter than the existing ones for some classes of quantum states.展开更多
We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels： amplitude damping channel, phase damping channel, depolarizing channel and bit flit ...We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels： amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qnbit states. We show that the amplitude damping channel, phase damping channel, and depolarizing channel do not change the coherence-induced state ordering by l1 norm of coherence, relative entropy of coherence, geometric measure of coherence, and Tsallis relative α-entropies, while the bit flit channel does change for some special cases.展开更多
Based on the resource theory for quantifying the coherence of quantum channels, we introduce a new coherence quantifier for quantum channels via maximum relative entropy. We prove that the maximum relative entropy for...Based on the resource theory for quantifying the coherence of quantum channels, we introduce a new coherence quantifier for quantum channels via maximum relative entropy. We prove that the maximum relative entropy for coherence of quantum channels is directly related to the maximally coherent channels under a particular class of superoperations, which results in an operational interpretation of the maximum relative entropy for coherence of quantum channels. We also introduce the conception of subsuperchannels and sub-superchannel discrimination. For any quantum channels, we show that the advantage of quantum channels in sub-superchannel discrimination can be exactly characterized by the maximum relative entropy of coherence for quantum channels. Similar to the maximum relative entropy of coherence for channels, the robustness of coherence for quantum channels has also been investigated. We show that the maximum relative entropy of coherence for channels provides new operational interpretations of robustness of coherence for quantum channels and illustrates the equivalence of the dephasing-covariant superchannels,incoherent superchannels, and strictly incoherent superchannels in these two operational tasks.展开更多
In this review, we introduce some methods for detecting or measuring entanglement. Several non- linear entanglement witnesses are presented. We derive a series of Bell inequalities whose maximally violations for any m...In this review, we introduce some methods for detecting or measuring entanglement. Several non- linear entanglement witnesses are presented. We derive a series of Bell inequalities whose maximally violations for any multipartite qubit states can be calculated by using our formulas. Both the non- linear entanglement witnesses and the Bell inequalities can be operated experimentally. Thus they supply an effective way for detecting entanglement. We also introduce some experimental methods to measure the entanglement of formation, and the lower bound of the convex-roof extension of negativity.展开更多
The gradient descent approach is the key ingredient in variational quantum algorithms and machine learning tasks,which is an optimization algorithm for finding a local minimum of an objective function.The quantum vers...The gradient descent approach is the key ingredient in variational quantum algorithms and machine learning tasks,which is an optimization algorithm for finding a local minimum of an objective function.The quantum versions of gradient descent have been investigated and implemented in calculating molecular ground states and optimizing polynomial functions.Based on the quantum gradient descent algorithm and Choi-Jamiolkowski isomorphism,we present approaches to simulate efficiently the nonequilibrium steady states of Markovian open quantum many-body systems.Two strategies are developed to evaluate the expectation values of physical observables on the nonequilibrium steady states.Moreover,we adapt the quantum gradient descent algorithm to solve linear algebra problems including linear systems of equations and matrix-vector multiplications,by converting these algebraic problems into the simulations of closed quantum systems with well-defined Hamiltonians.Detailed examples are given to test numerically the effectiveness of the proposed algorithms for the dissipative quantum transverse Ising models and matrix-vector multiplications.展开更多
We study the skew information-based coherence of quantum states and derive explicit formulas for Werner states and isotropic states in a set of autotensors of mutually unbiased bases(MUBs).We also give surfaces of ske...We study the skew information-based coherence of quantum states and derive explicit formulas for Werner states and isotropic states in a set of autotensors of mutually unbiased bases(MUBs).We also give surfaces of skew information-based coherence for Bell-diagonal states and a special class of X states in both computational basis and in MUBs.Moreover,we depict the surfaces of the skew information-based coherence for Bell-diagonal states under various types of local nondissipative quantum channels.The results show similar as well as different features compared with relative entropy of coherence and l1 norm of coherence.展开更多
We investigate quantum phase transitions in XY spin models using Dzyaloshinsky-Moriya(DM) interactions. We identify the quantum critical points via quantum Fisher information and quantum coherence, finding that higher...We investigate quantum phase transitions in XY spin models using Dzyaloshinsky-Moriya(DM) interactions. We identify the quantum critical points via quantum Fisher information and quantum coherence, finding that higher DM couplings suppress quantum phase transitions. However, quantum coherence(characterized by the l_1-norm and relative entropy) decreases as the DM coupling increases. Herein, we present both analytical and numerical results.展开更多
We investigate the total variance of a quantum state with respect to a complete set of mutually complementary measurements and its relation to the Brukner–Zeilinger invariant information.By summing the variances over...We investigate the total variance of a quantum state with respect to a complete set of mutually complementary measurements and its relation to the Brukner–Zeilinger invariant information.By summing the variances over any complete set of mutually unbiased measurements and general symmetric informationally complete measurements respectively,we show that the Brukner–Zeilinger invariant information associated with such types of quantum measurements is equal to the difference between the maximal variance and the total variance obtained.These results provide an operational link between the previous interpretations of the Brukner–Zeilinger invariant information.展开更多
In this work,we study the local distinguishability of maximally entangled states(MESs).In particular,we are concerned with whether any fixed number of MESs can be locally distinguishable for sufficiently large dimensi...In this work,we study the local distinguishability of maximally entangled states(MESs).In particular,we are concerned with whether any fixed number of MESs can be locally distinguishable for sufficiently large dimensions.Fan and Tian et al.have already obtained two satisfactory results for the generalized Bell states(GBSs)and the qudit lattice states when applied to prime or prime power dimensions.We construct a general twist-teleportation scheme for any orthonormal basis with MESs that is inspired by the method used in[Phys.Rev.A 70,022304(2004)].Using this teleportation scheme,we obtain a sufficient and necessary condition for one-way distinguishable sets of MESs,which include the GBSs and the qudit lattice states as special cases.Moreover,we present a generalized version of the results in[Phys.Rev.A 92,042320(2015)]for the arbitrary dimensional case.展开更多
As one of the most striking features of quantum phenomena,quantum entanglement has been identified as a key nonlocal resource in quantum information processing such as quantum cryptography.In particular,the maximally ...As one of the most striking features of quantum phenomena,quantum entanglement has been identified as a key nonlocal resource in quantum information processing such as quantum cryptography.In particular,the maximally entangled states give rise to the best fidelity in general,for instance,perfect teleportation.展开更多
基金the National Natural Science Foundation of China(Grant Nos.12075159,12171044,and 12175147)the Natural Science Foundation of Beijing(Grant No.Z190005)+2 种基金the Academician Innovation Platform of Hainan ProvinceShenzhen Institute for Quantum Science and EngineeringSouthern University of Science and Technology(Grant No.SIQSE202001)。
文摘Quantum coherence is a fundamental feature of quantum physics and plays a significant role in quantum information processing.By generalizing the resource theory of coherence from von Neumann measurements to positive operatorvalued measures(POVMs),POVM-based coherence measures have been proposed with respect to the relative entropy of coherence,the l_(1) norm of coherence,the robustness of coherence and the Tsallis relative entropy of coherence.We derive analytically the lower and upper bounds on these POVM-based coherence of an arbitrary given superposed pure state in terms of the POVM-based coherence of the states in superposition.Our results can be used to estimate range of quantum coherence of superposed states.Detailed examples are presented to verify our analytical bounds.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11765016 and 11675113)the Natural Science Foundation of Beijing,China(Grant No.KZ201810028042)Beijing Natural Science Foundation,China(Grant No.Z190005).
文摘Quantum entanglement plays essential roles in quantum information processing.The monogamy and polygamy relations characterize the entanglement distributions in the multipartite systems.We present a class of monogamy inequalities related to theµ-th power of the entanglement measure based on Renyi-αentropy,as well as polygamy relations in terms of theµ-th power of Renyi-αentanglement of assistance.These monogamy and polygamy relations are shown to be tighter than the existing ones.
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.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075159 and 11847209)Beijing Natural Science Foundation(Grant No.Z190005)+2 种基金Academy for Multidisciplinary Studies,Capital Normal University,the Academician Innovation Platform of Hainan Province,Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology(Grant No.SIQSE202001)the China Postdoctoral Science Foundation funded project(Grant No.2019M650811)the China Scholarship Council(Grant No.201904910005).
文摘We investigate the monogamy and polygamy inequalities of arbitrary multipartite quantum states,and provide new classes of monogamy and polygamy inequalities of multiqubit entanglement in terms o f concurrence,entanglement of formation,negativity,and Tsallis-q entanglement,respectively.We show that these new monogamy and polygamy inequality relations are tighter than the existing ones with detailed examples.
基金supported by National Natural Science Foundation of China(Grant Nos.12161056,12075159,12171044)Jiangxi Provincial Natural Science Foundation(Grant No.20232ACB211003)the Academician Innovation Platform of Hainan Province。
文摘We establish tighter uncertainty relations for arbitrary finite observables via(α,β,γ)weighted Wigner–Yanase–Dyson((α,β,γ)WWYD)skew information.The results are also applicable to the(α,γ)weighted Wigner–Yanase–Dyson((α,γ)WWYD)skew information and the weighted Wigner–Yanase–Dyson(WWYD)skew information.We also present tighter lower bounds for quantum channels and unitary channels via(α,β,γ)modified weighted Wigner–Yanase–Dyson((α,β,γ)MWWYD)skew information.Detailed examples are provided to illustrate the tightness of our uncertainty relations.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.12065021,12075159,12171044,and 12175147)。
文摘Quantum uncertainty relations constrain the precision of measurements across multiple non-commuting quantum mechanical observables.Here,we introduce the concept of optimal observable sets and define the tightest uncertainty constants to accurately describe these measurement uncertainties.For any quantum state,we establish optimal sets of three observables for both product and summation forms of uncertainty relations,and analytically derive the corresponding tightest uncertainty constants.We demonstrate that the optimality of these sets remains consistent regardless of the uncertainty relation form.Furthermore,the existence of the tightest constants excludes the validity of standard real quantum mechanics,underscoring the essential role of complex numbers in this field.Additionally,our findings resolve the conjecture posed in[Phys.Rev.Lett.118,180402(2017)],offering novel insights and potential applications in understanding preparation uncertainties.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.12126314,12126351,11861031,12075159,and 12171044the Hainan Provincial Natural Science Foundation of China under Grant No.121RC539+3 种基金the Specific Research Fund of the Innovation Platform for Academicians of Hainan Province under Grant No.YSPTZX202215Beijing Natural Science Foundation(Grant No.Z190005)Academy for Multidisciplinary Studies,Capital Normal UniversityShenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology(No.SIQSE202001).
文摘The Bell nonlocality is closely related to the foundations of quantum physics and has significant applications to security questions in quantum key distributions.In recent years,the sharing ability of the Bell nonlocality has been extensively studied.The nonlocality of quantum network states is more complex.We first discuss the sharing ability of the simplest bilocality under unilateral or bilateral POVM measurements,and show that the nonlocality sharing ability of network quantum states under unilateral measurements is similar to the Bell nonlocality sharing ability,but different under bilateral measurements.For the star network scenarios,we present for the first time comprehensive results on the nonlocality sharing properties of quantum network states,for which the quantum nonlocality of the network quantum states has a stronger sharing ability than the Bell nonlocality.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.12075159 and 12171044Beijing Natural Science Foundation(Grant No.Z190005)the Academician Innovation Platform of Hainan Province.
文摘We present protocols to generate quantum entanglement on nonlocal magnons in hybrid systems composed of yttrium iron garnet(YIG)spheres,microwave cavities and a superconducting(SC)qubit.In the schemes,the YIGs are coupled to respective microwave cavities in resonant way,and the SC qubit is placed at the center of the cavities,which interacts with the cavities simultaneously.By exchanging the virtual photon,the cavities can indirectly interact in the far-detuning regime.Detailed protocols are presented to establish entanglement for two,three and arbitrary N magnons with reasonable fidelities.
基金funded by the NSF of China(Grant Nos.11675119,12075159,11575125,12171044)Shanxi Education Department Fund(2020L0543)+3 种基金Beijing Natural Science Foundation(Z190005)Academy for Multidisciplinary Studies,Capital Normal Universitythe Academician Innovation Platform of Hainan Provincethe Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology(No.SIQSE202001)
文摘Quantum state discrimination is an important part of quantum information processing.We investigate the discrimination of coherent states through a Jaynes-Cummings(JC)model interaction between the field and the ancilla without rotation wave approximation(RWA).We show that the minimum failure probability can be reduced as RWA is eliminated from the JC model and the non-RWA terms accompanied by the quantum effects of fields(e.g.the virtualphoton process in the JC model without RWA)can enhance the state discrimination.The JC model without RWA for unambiguous state discrimination is superior to ambiguous state discrimination,particularly when the number of sequential measurements increases.Unambiguous state discrimination implemented via the non-RWA JC model is beneficial to saving resource costs.
基金supported by the National Natural Science Foundation of China(Grant Nos.12161056,12075159,12171044)Beijing Natural Science Foundation(Grant No.Z190005)the Academician Innovation Platform of Hainan Province。
文摘Quantum coherence plays a central role in Grover’s search algorithm.We study the Tsallis relative a entropy of coherence dynamics of the evolved state in Grover’s search algorithm.We prove that the Tsallis relative a entropy of coherence decreases with the increase of the success probability,and derive the complementarity relations between the coherence and the success probability.We show that the operator coherence of the first H■relies on the size of the database N,the success probability and the target states.Moreover,we illustrate the relationships between coherence and entanglement of the superposition state of targets,as well as the production and deletion of coherence in Grover iterations.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11805143,11675113Key Project of Beijing Municipal Commission of Education under Grant No.KZ201810028042
文摘Monogamy and polygamy relations characterize the distributions of entanglement in multipartite systems.We provide classes of monogamy and polygamy inequalities of multiqubit entanglement in terms of concurrence, entanglement of formation, negativity, Tsallis-q entanglement, and Rényi-α entanglement, respectively. We show that these inequalities are tighter than the existing ones for some classes of quantum states.
文摘We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels： amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qnbit states. We show that the amplitude damping channel, phase damping channel, and depolarizing channel do not change the coherence-induced state ordering by l1 norm of coherence, relative entropy of coherence, geometric measure of coherence, and Tsallis relative α-entropies, while the bit flit channel does change for some special cases.
基金supported by the National Natural Science Foundation of China(Grant Nos.11847209,61727801,and 12075159)the China Postdoctoral Science Foundation(Grant No.2019M650811)+4 种基金the China Scholarship Council(Grant No.201904910005)Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology(Grant No.SIQSE202001)Beijing Natural Science Foundation(Grant No.Z190005)the Academician Innovation Platform of Hainan ProvinceAcademy for Multidisciplinary Studies,Capital Normal University。
文摘Based on the resource theory for quantifying the coherence of quantum channels, we introduce a new coherence quantifier for quantum channels via maximum relative entropy. We prove that the maximum relative entropy for coherence of quantum channels is directly related to the maximally coherent channels under a particular class of superoperations, which results in an operational interpretation of the maximum relative entropy for coherence of quantum channels. We also introduce the conception of subsuperchannels and sub-superchannel discrimination. For any quantum channels, we show that the advantage of quantum channels in sub-superchannel discrimination can be exactly characterized by the maximum relative entropy of coherence for quantum channels. Similar to the maximum relative entropy of coherence for channels, the robustness of coherence for quantum channels has also been investigated. We show that the maximum relative entropy of coherence for channels provides new operational interpretations of robustness of coherence for quantum channels and illustrates the equivalence of the dephasing-covariant superchannels,incoherent superchannels, and strictly incoherent superchannels in these two operational tasks.
文摘In this review, we introduce some methods for detecting or measuring entanglement. Several non- linear entanglement witnesses are presented. We derive a series of Bell inequalities whose maximally violations for any multipartite qubit states can be calculated by using our formulas. Both the non- linear entanglement witnesses and the Bell inequalities can be operated experimentally. Thus they supply an effective way for detecting entanglement. We also introduce some experimental methods to measure the entanglement of formation, and the lower bound of the convex-roof extension of negativity.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075159,12171044,and 12005015)Beijing Natural Science Foundation(Grant No.Z190005)Academy for Multidisciplinary Studies,Capital Normal University,Academician Innovation Platform of Hainan Province,and Shenzhen Institute for Quantum Science and Engineering,Southern University of Science and Technology(Grant No.SIQSE202001)。
文摘The gradient descent approach is the key ingredient in variational quantum algorithms and machine learning tasks,which is an optimization algorithm for finding a local minimum of an objective function.The quantum versions of gradient descent have been investigated and implemented in calculating molecular ground states and optimizing polynomial functions.Based on the quantum gradient descent algorithm and Choi-Jamiolkowski isomorphism,we present approaches to simulate efficiently the nonequilibrium steady states of Markovian open quantum many-body systems.Two strategies are developed to evaluate the expectation values of physical observables on the nonequilibrium steady states.Moreover,we adapt the quantum gradient descent algorithm to solve linear algebra problems including linear systems of equations and matrix-vector multiplications,by converting these algebraic problems into the simulations of closed quantum systems with well-defined Hamiltonians.Detailed examples are given to test numerically the effectiveness of the proposed algorithms for the dissipative quantum transverse Ising models and matrix-vector multiplications.
基金supported by the National Natural Science Foundation of China(11701259,11461045,11675113)the China Scholarship Council(201806825038)+2 种基金the Key Project of Beijing Municipal Commission of Education(KZ201810028042)the Beijing Natural Science Foundation(Z190005)the Academy for Multidisciplinary Studies,Capital Normal University。
文摘We study the skew information-based coherence of quantum states and derive explicit formulas for Werner states and isotropic states in a set of autotensors of mutually unbiased bases(MUBs).We also give surfaces of skew information-based coherence for Bell-diagonal states and a special class of X states in both computational basis and in MUBs.Moreover,we depict the surfaces of the skew information-based coherence for Bell-diagonal states under various types of local nondissipative quantum channels.The results show similar as well as different features compared with relative entropy of coherence and l1 norm of coherence.
基金supported by the National Natural Science Foundation of China(Grant Nos.11675113,and 11765016)the Natural Science Foundation of Beijing(Grant No.KZ201810028042)Jiangxi Education Department Fund(Grant Nos.GJJ161056,and KJLD14088)
文摘We investigate quantum phase transitions in XY spin models using Dzyaloshinsky-Moriya(DM) interactions. We identify the quantum critical points via quantum Fisher information and quantum coherence, finding that higher DM couplings suppress quantum phase transitions. However, quantum coherence(characterized by the l_1-norm and relative entropy) decreases as the DM coupling increases. Herein, we present both analytical and numerical results.
基金supported by the National Natural Science Foundation of China under Grant Nos.11805143 and 11675113Beijing Municipal Commission of Education under Grant No.KZ201810028042。
文摘We investigate the total variance of a quantum state with respect to a complete set of mutually complementary measurements and its relation to the Brukner–Zeilinger invariant information.By summing the variances over any complete set of mutually unbiased measurements and general symmetric informationally complete measurements respectively,we show that the Brukner–Zeilinger invariant information associated with such types of quantum measurements is equal to the difference between the maximal variance and the total variance obtained.These results provide an operational link between the previous interpretations of the Brukner–Zeilinger invariant information.
基金supported by the National Natural Science Foundation of China(Grant Nos.11675113,11871295,and 11901084)Beijing Municipal Commission of Education(Grant No.KM201810011009)+1 种基金Beijing Natural Science Foundation(Grant No.Z190005)the Research Startup Funds of Dongguan University of Technology(Grant No.GC300501-103)。
文摘In this work,we study the local distinguishability of maximally entangled states(MESs).In particular,we are concerned with whether any fixed number of MESs can be locally distinguishable for sufficiently large dimensions.Fan and Tian et al.have already obtained two satisfactory results for the generalized Bell states(GBSs)and the qudit lattice states when applied to prime or prime power dimensions.We construct a general twist-teleportation scheme for any orthonormal basis with MESs that is inspired by the method used in[Phys.Rev.A 70,022304(2004)].Using this teleportation scheme,we obtain a sufficient and necessary condition for one-way distinguishable sets of MESs,which include the GBSs and the qudit lattice states as special cases.Moreover,we present a generalized version of the results in[Phys.Rev.A 92,042320(2015)]for the arbitrary dimensional case.
文摘As one of the most striking features of quantum phenomena,quantum entanglement has been identified as a key nonlocal resource in quantum information processing such as quantum cryptography.In particular,the maximally entangled states give rise to the best fidelity in general,for instance,perfect teleportation.
