We present a scheme for symmetric controlled remote preparation of an arbitrary 2-qudit state form a sender to either of the two receivers via positive operator-valued measurement and pure entangled two-particle state...We present a scheme for symmetric controlled remote preparation of an arbitrary 2-qudit state form a sender to either of the two receivers via positive operator-valued measurement and pure entangled two-particle states. The first sender transforms the quantum channel shared by all the agents via POVM according to her knowledge of prepared state. All the senders perform singIe- or two-particle projective measurements on their entangled particles and the receiver can probabilisticaly reconstruct the original state on her entangled particles via unitary transformation and auxiliary qubit. The scheme is optimal as the probability which the receiver prepares the original state equals to the entanglement of the quantum channel. Moreover, it is more convenience in application than others as it requires only two-particle entanglements for preparing an arbitrary two-qudit state.展开更多
Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment c...Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment changed.This change will lead to the transformation of sensitive hydrogels stability,thus phase transition of hydrogel take place.Here,we present a new free density energy function,which considers the non-gaussianity of the polymer network,chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory.A program to calculate the phase transition temperature was written based on new free energy function.Taking PNIPAM hydrogel as an example,the effects of network entanglement on the phase transition temperature of hydrogel were studied by analyzing the microstructure parameters of the hydrogel networks.Analytical results suggest a significant relationship between phase transition temperature and entanglement network.展开更多
A hybrid cryptographic system providing digital authentication is described and analyzed in this paper. The proposed cryptosystem incorporates three features: complexity of the discrete logarithm problem, complexity o...A hybrid cryptographic system providing digital authentication is described and analyzed in this paper. The proposed cryptosystem incorporates three features: complexity of the discrete logarithm problem, complexity of integer factorization of a product of two large primes and a combination of symmetric and asymmetric keys. In order to make the cryptosystem less vulnerable to cryptanalytic attacks a concept of digital entanglements is introduced. As a result, the proposed cryptographic system has four layers (entanglement-encryption- decryption-disentanglement). It is shown that in certain instances the proposed communication cryptocol is many times faster than the RSA cryptosystem. Examples provided in the paper illustrate details of the proposed authentication cryptocol.展开更多
Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low hysteresis.By considering the evolution of randomly distributed entanglements within the polymer ...Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low hysteresis.By considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these hydrogels.In the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each corner.By employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these hydrogels.The present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their elasticity.We also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these hydrogels.Overall,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.展开更多
We theoretically investigate the entanglement properties in a hybrid system consisting of an optical cavity-array coupled to a mechanical resonator. We show that the steady state of the system presents bipartite conti...We theoretically investigate the entanglement properties in a hybrid system consisting of an optical cavity-array coupled to a mechanical resonator. We show that the steady state of the system presents bipartite continuous variable entanglement in an experimentally accessible parameter regime. The effects of the cavity-cavity coupling strength on the bipartite entanglements in the field-mirror subsystem and in the field-field subsystem are studied. We further find that the entanglement between the adjacent cavity and the movable mirror can be entirely transferred to the distant cavity and mirror by properly choosing the cavity detunings and the coupling strength in the two-cavity case. Surprisingly, such a remote macroscopic entanglement tends to be stable in the large coupling regime and persists for environment temperatures at above 25 K in the three-cavity case. Such optomechanical systems can be used for the realization of continuous variable quantum information interfaces and networks.展开更多
Based on Thiele-Cohen model, a swelling equation was derived by introducing the interaction parameters of a three-component system of polymer Ⅰ-polymer Ⅱ-solvent, which is a reasonable representation of the swelling...Based on Thiele-Cohen model, a swelling equation was derived by introducing the interaction parameters of a three-component system of polymer Ⅰ-polymer Ⅱ-solvent, which is a reasonable representation of the swelling behavior of general homogeneous IPNs. The degrees of equilibrium swelling of polyvinyl acetate/polymethyl actylate (PVAc/PMA) IPNs were compared between the theoretical and experimental values. The obvious effects of mutual entanglements were observed.展开更多
Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum...Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum communication, and utilize the logical relationship between the measurements of each node to derive the unitary operation performed by the end node. The hierarchical simultaneous entanglement switching(HSES) method is adopted, resulting in a significant reduction in the consumption of classical information compared to multi-hop quantum teleportation(QT)based on general simultaneous entanglement switching(SES). In addition, the proposed protocol is simulated on the IBM Quantum Experiment platform(IBM QE). Then, the data obtained from the experiment are analyzed using quantum state tomography, which verifies the protocol's good fidelity and accuracy. Finally, by calculating fidelity, we analyze the impact of four different types of noise(phase-damping, amplitude-damping, phase-flip and bit-flip) in this protocol.展开更多
The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes ...The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes used there are incapable of cloning quantum entangled states in multipartite systems.Few schemes were proposed for cloning multiparticle states,which consume more entanglement resources with loss of qubits,and the fidelity of the cloned state is relatively low.In this paper,cloning schemes for bipartite and tripartite entangled states based on photonic quantum walk and entanglement swapping are proposed.The results show that according to the proposed schemes,two high-fidelity(up to 0.75)cloned states can be obtained with less quantum resource consumption.Because of the simple cloning steps,few quantum resources and high fidelity,these schemes are both efficient and feasible.Moreover,this cloning machine eliminates the need for tracing out cloning machine,thereby minimizing resource waste.展开更多
Entanglement plays a key role in quantum physics, but how much information it can extract from many-body systems is still an open question, particularly regarding quantum criticalities and emergent symmetries. In this...Entanglement plays a key role in quantum physics, but how much information it can extract from many-body systems is still an open question, particularly regarding quantum criticalities and emergent symmetries. In this work, we systematically study the entanglement entropy(EE) and derivative entanglement entropy(DEE) near quantum phase transitions in various quantum many-body systems. A one-parameter scaling relation between the DEE and system size at the critical point has been derived for the first time, which successfully obtains the critical exponent via data collapse. Furthermore, we find that the EE peaks at the(emergent) symmetryenhanced first-order transition, reflecting higher symmetry breaking. This work provides a new paradigm for quantum many-body research from the perspective of EE and DEE.展开更多
The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a...The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a reliable and universally applicable method for enhancing and regulating entanglement. Here we demonstrate how a few-cycle intense laser field can significantly enhance the degree of entanglement compared to its multi-cycle counterpart, using the example of electron–electron entanglement of orbital angular momentum(OAM) states in recollision-excitation non-sequential double ionization of Ar atoms. By confining the ionization dynamics to a specific narrow time window, the few-cycle pulse purifies the electron trajectories, thereby ensuring high coherence between entangled OAM channels and enhancing entanglement. Furthermore, the degree of entanglement can be efficiently modulated by varying the carrier envelope phase of the few-cycle laser pulse, which is achieved by altering the population across OAM channels. Optimizing coherence through electron trajectory purification with a designed specific temporal waveform of laser field provides a general pathway for enhancing entanglement in laser-induced systems.展开更多
Hybrid entangled states are crucial in quantum physics,offering significant benefits for hybrid quantum communication and quantum computation,and then the conversion of hybrid entangled states is equally critical.This...Hybrid entangled states are crucial in quantum physics,offering significant benefits for hybrid quantum communication and quantum computation,and then the conversion of hybrid entangled states is equally critical.This paper presents two novel schemes,that is,one converts the two-qubit hybrid Knill–Laflamme–Milburn(KLM)entangled state into Bell states and the other one transforms the three-qubit hybrid KLM state into Greenberger–Horne–Zeilinger(GHZ)states assisted by error-predicted and parity-discriminated devices.Importantly,the integration of single photon detectors into the parity-discriminated device enhances predictive capabilities,mitigates potential failures,and facilitates seamless interaction between the nitrogen-vacancy center and photons,so the two protocols operate in an error-predicted way,improving the experimental feasibility.Additionally,our schemes demonstrate robust fidelities(close to 1)and efficiencies,indicating their feasibility with existing technology.展开更多
Entanglement asymmetry(EA) has emerged as a powerful tool for characterizing symmetry breaking in quantum many-body systems. In this Letter, we explore how symmetry is dynamically broken through the lens of EA in two ...Entanglement asymmetry(EA) has emerged as a powerful tool for characterizing symmetry breaking in quantum many-body systems. In this Letter, we explore how symmetry is dynamically broken through the lens of EA in two distinct scenarios: a non-symmetric Hamiltonian quench and a non-symmetric random quantum circuit, with a particular focus on U(1) symmetry. In the former case, symmetry remains broken in the subsystem at late times, whereas in the latter case, the symmetry is initially broken and subsequently restored, consistent with the principles of quantum thermalization. Notably, the growth of EA exhibits unexpected overshooting behavior at early times in both contexts, contrasting with the behavior of charge variance. We also consider dynamics of non-symmetric initial states under the symmetry-breaking evolution. Due to the competition of symmetry-breaking in both the initial state and Hamiltonian, the early-time EA can increase and decrease, while quantum Mpemba effects remain evident despite the weak symmetry-breaking in both settings.展开更多
In this second part of a study about quantum field oscillators with sub-oscillators and semi-quanta (IQuO), it is possible to show that in the initial phase of an interaction between two particles a no-dynamic process...In this second part of a study about quantum field oscillators with sub-oscillators and semi-quanta (IQuO), it is possible to show that in the initial phase of an interaction between two particles a no-dynamic process of reduction from a non-local to a local state takes place which cannot be described by Hamiltonian. We then describe the coupling of two IQuO of different particle-fields either at one point in space or at two distant points via an intermediary chain of coupled IQuO. The first aspect provides an understanding of the basic processes of creating and annihilating a pair. The second aspect describes the behaviour of two electrically charged particles through a process of phase shifts between the respective IQuO chains (CF1, CF2) implemented in a quantum entanglement via an intermediary chain (CB) of IQuO that originates changes in the direction of the two (CF1, CF2) distance-correlated ones. Thus, the semi-quanta structure of an IQuO and quantum entanglement identify the origin of the empirical law of attraction and repulsion between two electric charges.展开更多
A classification of multipartite entanglement is introduced for pure and mixed states.The classification is based on the distribution of entanglement between the qubits of a given system,with a mathematical framework ...A classification of multipartite entanglement is introduced for pure and mixed states.The classification is based on the distribution of entanglement between the qubits of a given system,with a mathematical framework used to characterize fully entangled states.Then we use current machine learning and deep learning techniques to automatically classify a random state of two,three,and four qubits without the need to compute the amount of the different types of entanglement in each run;rather this is done only in the learning process.The technique shows high,near-perfect,accuracy in the case of pure states.As expected,this accuracy drops,more or less,when dealing with mixed states and when increasing the number of parties involved.展开更多
Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other cat...Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other categories of entanglement,maximally HESs inevitably degrade to mixed states due to the environmental noise and operational imperfections.To address the degradation problem,measurement-based entanglement purification offers a feasible and robust solution alternative to conventional gate-based purification methods.In this paper,we propose a measurement-based hybrid entanglement purification protocol(MB-HEPP)for a certain kind of HES which consists of polarization photons and coherent states.We extend our methodology to several conditions,such as the multi-copy and multi-party scenarios,and the photon-loss condition.Compared with previous HEPPs,this protocol has several advantages.First,it does not depend on post-selection and the purified HESs can be retained for further application.Second,it does not require the Bell state measurement,but only uses the parity check with conventional linear optical elements,which makes it have the higher success probability and more feasible.Our MB-HEPP has potential applications in future heterogeneous quantum networks.展开更多
We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel ...We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel transmission efficiency and measurement precision,we demonstrate superclassical timing resolution in both lossless and lossy regimes.Theoretical analysis and numerical simulations reveal that,under a lossless channel,the precision gain increases with the degree of entanglement,approaching the Heisenberg limit.Importantly,in lossy channels,the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement.For transmission efficiencies above50%,the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized.Moreover,by optimizing intra-group and inter-group covariances in the multi-structured entangled state,we achieve substantial precision gains even at low transmission efficiencies(~30%),demonstrating its robustness against loss.This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation.Future implementation could extend to satellite-based quantum positioning,remote sensing,quantum illumination,and other fields that require high-precision ranging in lossy environments.The protocol establishes a universal framework for loss-tolerant quantum metrology,advancing the practical deployment of quantum-enhanced sensing in real-world applications.展开更多
Due to their high mechanical compliance and excellent biocompatibility,conductive hydrogels exhibit significant potential for applications in flexible electronics.However,as the demand for high sensitivity,superior me...Due to their high mechanical compliance and excellent biocompatibility,conductive hydrogels exhibit significant potential for applications in flexible electronics.However,as the demand for high sensitivity,superior mechanical properties,and strong adhesion performance continues to grow,many conventional fabrication methods remain complex and costly.Herein,we propose a simple and efficient strategy to construct an entangled network hydrogel through a liquid-metal-induced cross-linking reaction,hydrogel demonstrates outstanding properties,including exceptional stretchability(1643%),high tensile strength(366.54 kPa),toughness(350.2 kJ m^(−3)),and relatively low mechanical hysteresis.The hydrogel exhibits long-term stable reusable adhesion(104 kPa),enabling conformal and stable adhesion to human skin.This capability allows it to effectively capture high-quality epidermal electrophysiological signals with high signal-to-noise ratio(25.2 dB)and low impedance(310 ohms).Furthermore,by integrating advanced machine learning algorithms,achieving an attention classification accuracy of 91.38%,which will significantly impact fields like education,healthcare,and artificial intelligence.展开更多
Conversion between different types of entangled states is an interesting problem in quantum mechanics.But research on the conversion between the Greenberger-Horne-Zeilinger(GHZ)state and Knill-Laflamme-Milburn(KLM)sta...Conversion between different types of entangled states is an interesting problem in quantum mechanics.But research on the conversion between the Greenberger-Horne-Zeilinger(GHZ)state and Knill-Laflamme-Milburn(KLM)state in an atomic system has not been reported.In this paper,we propose a scheme to realize the interconversion(one-step)between the GHZ state and KLM state with Rydberg atoms.By utilizing Rydberg-mediated interactions,we simplify the system.By combining a Lie-transform-based pulse design,the evolution path is built up to realize interconversion of the GHZ state and KLM state.The numerical simulation result shows that the present scheme is robust against decoherence and operational imperfection.展开更多
A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann paramete...A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann parameters. A general expression for the density matrix of the composite system of angular momenta j1and j2is obtained. In this matrix representation violations of the Bell-Clauser-Horne-Shimony-Holt inequalities are established for the X-states of a qubit-qubit, pure and mixed, composite system, as well as for a qubit-qutrit density matrix. In both cases maximal violation of the Bell inequalities can be reached, i.e., the Cirel’son limit. A correlation between the entanglement measure and a strong violation of the Bell factor is also given. For the qubit-qutrit composite system a time-dependent convex combination of the density matrix of the eigenstates of a two-particle Hamiltonian system is used to determine periodic maximal violations of the Bell’s inequality.展开更多
We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system...We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system comprises an optical cavity, a two-level atomic ensemble and a mechanical resonator that possesses Duffing nonlinearity. The interaction between these components is mediated by the cavity mode, which is driven by an external laser. Our findings indicate that optimizing the coupling strengths between photons and phonons, as well as between atoms and the cavity,leads to maximal entanglement and EPR steering. The amplitude of the driving laser plays a pivotal role in enhancing the coupling between photons and phonons, and the system maintains robust entanglement and EPR steering even under high dissipation, thereby mitigating the constraints on initial conditions and parameter precision. Remarkably, the Duffing nonlinearity enhances the system's resistance to thermal noise, ensuring its stability and entanglement protection. Our analysis of EPR steering conditions reveals that the party with lower dissipation exhibits superior stability and a propensity to steer the party with higher dissipation. These discoveries offer novel perspectives for advancing quantum information processing and communication technologies.展开更多
基金Supported by Program for Natural Science Foundation of Guangxi under Grant No. 2011GxNSFB018062, Excellent Talents in Guangxi Higher Education Institutions under Grant No. [2012]41, Key program of Cuangxi University for Nationalities under Grant No. [2011]317 and the Bagui Scholarship Project
文摘We present a scheme for symmetric controlled remote preparation of an arbitrary 2-qudit state form a sender to either of the two receivers via positive operator-valued measurement and pure entangled two-particle states. The first sender transforms the quantum channel shared by all the agents via POVM according to her knowledge of prepared state. All the senders perform singIe- or two-particle projective measurements on their entangled particles and the receiver can probabilisticaly reconstruct the original state on her entangled particles via unitary transformation and auxiliary qubit. The scheme is optimal as the probability which the receiver prepares the original state equals to the entanglement of the quantum channel. Moreover, it is more convenience in application than others as it requires only two-particle entanglements for preparing an arbitrary two-qudit state.
基金support from the National Natural Science Foundation of China(Grant Nos.11520007,11572109 and 11632005)the Hebei Natural Science Foundation of China(Grant No.A2016201198)technology research in Colleges and Universities of Hebei Province(Grant No.ZD2017006)are gratefully acknowledged。
文摘Phase transition of hydrogel,which is polymerized by polymer network,can be regarded as the transition of polymer network stability.The stability of the polymer network might be changed when the external environment changed.This change will lead to the transformation of sensitive hydrogels stability,thus phase transition of hydrogel take place.Here,we present a new free density energy function,which considers the non-gaussianity of the polymer network,chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory.A program to calculate the phase transition temperature was written based on new free energy function.Taking PNIPAM hydrogel as an example,the effects of network entanglement on the phase transition temperature of hydrogel were studied by analyzing the microstructure parameters of the hydrogel networks.Analytical results suggest a significant relationship between phase transition temperature and entanglement network.
文摘A hybrid cryptographic system providing digital authentication is described and analyzed in this paper. The proposed cryptosystem incorporates three features: complexity of the discrete logarithm problem, complexity of integer factorization of a product of two large primes and a combination of symmetric and asymmetric keys. In order to make the cryptosystem less vulnerable to cryptanalytic attacks a concept of digital entanglements is introduced. As a result, the proposed cryptographic system has four layers (entanglement-encryption- decryption-disentanglement). It is shown that in certain instances the proposed communication cryptocol is many times faster than the RSA cryptosystem. Examples provided in the paper illustrate details of the proposed authentication cryptocol.
基金Project supported by the Key Research Project of Zhejiang Laboratory (No.K2022NB0AC03)the National Natural Science Foundation of China (No.11872334)the National Natural Science Foundation of Zhejiang Province of China (No.LZ23A020004)。
文摘Highly entangled hydrogels exhibit excellent mechanical properties,including high toughness,high stretchability,and low hysteresis.By considering the evolution of randomly distributed entanglements within the polymer network upon mechanical stretches,we develop a constitutive theory to describe the large stretch behaviors of these hydrogels.In the theory,we utilize a representative volume element(RVE)in the shape of a cube,within which there exists an averaged chain segment along each edge and a mobile entanglement at each corner.By employing an explicit method,we decouple the elasticity of the hydrogels from the sliding motion of their entanglements,and derive the stress-stretch relations for these hydrogels.The present theoretical analysis is in agreement with experiment,and highlights the significant influence of the entanglement distribution within the hydrogels on their elasticity.We also implement the present developed constitutive theory into a commercial finite element software,and the subsequent simulations demonstrate that the exact distribution of entanglements strongly affects the mechanical behaviors of the structures of these hydrogels.Overall,the present theory provides valuable insights into the deformation mechanism of highly entangled hydrogels,and can aid in the design of these hydrogels with enhanced performance.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.91121023)the National Natural Science Foundation of China(Grant Nos.61378012 and 60978009)+2 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20124407110009)the National Basic Research Program of China(Grant Nos.2011CBA00200 and 2013CB921804)the Program for Changjiang Scholar and Innovative Research Team in Universities,China(Grant No.IRT1243)
文摘We theoretically investigate the entanglement properties in a hybrid system consisting of an optical cavity-array coupled to a mechanical resonator. We show that the steady state of the system presents bipartite continuous variable entanglement in an experimentally accessible parameter regime. The effects of the cavity-cavity coupling strength on the bipartite entanglements in the field-mirror subsystem and in the field-field subsystem are studied. We further find that the entanglement between the adjacent cavity and the movable mirror can be entirely transferred to the distant cavity and mirror by properly choosing the cavity detunings and the coupling strength in the two-cavity case. Surprisingly, such a remote macroscopic entanglement tends to be stable in the large coupling regime and persists for environment temperatures at above 25 K in the three-cavity case. Such optomechanical systems can be used for the realization of continuous variable quantum information interfaces and networks.
基金Project supported by the National Natural Science Foundation of China
文摘Based on Thiele-Cohen model, a swelling equation was derived by introducing the interaction parameters of a three-component system of polymer Ⅰ-polymer Ⅱ-solvent, which is a reasonable representation of the swelling behavior of general homogeneous IPNs. The degrees of equilibrium swelling of polyvinyl acetate/polymethyl actylate (PVAc/PMA) IPNs were compared between the theoretical and experimental values. The obvious effects of mutual entanglements were observed.
基金Project supported by the Open Fund of Anhui Key Laboratory of Mine Intelligent Equipment and Technology (Grant No. ZKSYS202204)the Talent Introduction Fund of Anhui University of Science and Technology (Grant No. 2021yjrc34)the Scientific Research Fund of Anhui Provincial Education Department (Grant No. KJ2020A0301)。
文摘Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum communication, and utilize the logical relationship between the measurements of each node to derive the unitary operation performed by the end node. The hierarchical simultaneous entanglement switching(HSES) method is adopted, resulting in a significant reduction in the consumption of classical information compared to multi-hop quantum teleportation(QT)based on general simultaneous entanglement switching(SES). In addition, the proposed protocol is simulated on the IBM Quantum Experiment platform(IBM QE). Then, the data obtained from the experiment are analyzed using quantum state tomography, which verifies the protocol's good fidelity and accuracy. Finally, by calculating fidelity, we analyze the impact of four different types of noise(phase-damping, amplitude-damping, phase-flip and bit-flip) in this protocol.
文摘The no-cloning theorem has sparked considerable interest in achieving high-fidelity approximate quantum cloning.Most of the previous studies mainly focused on the cloning of single particle states,and cloning schemes used there are incapable of cloning quantum entangled states in multipartite systems.Few schemes were proposed for cloning multiparticle states,which consume more entanglement resources with loss of qubits,and the fidelity of the cloned state is relatively low.In this paper,cloning schemes for bipartite and tripartite entangled states based on photonic quantum walk and entanglement swapping are proposed.The results show that according to the proposed schemes,two high-fidelity(up to 0.75)cloned states can be obtained with less quantum resource consumption.Because of the simple cloning steps,few quantum resources and high fidelity,these schemes are both efficient and feasible.Moreover,this cloning machine eliminates the need for tracing out cloning machine,thereby minimizing resource waste.
基金supported by the the National Natural Science Foundation of China(Grant Nos.12175015 for W.G.and 12174387 for L.Z.)the Chinese Academy of Sciences (Grant Nos.YSBR-057 and JZHKYPT-2021-08 for L.Z.)+1 种基金the Innovative Program for Quantum Science and Technology (Grant No.2021ZD0302600 for L.Z.)the start-up funding of Westlake University and the China Postdoctoral Science Foundation (Grant No.2024M752898 for Z.W.and Z.Y.)。
文摘Entanglement plays a key role in quantum physics, but how much information it can extract from many-body systems is still an open question, particularly regarding quantum criticalities and emergent symmetries. In this work, we systematically study the entanglement entropy(EE) and derivative entanglement entropy(DEE) near quantum phase transitions in various quantum many-body systems. A one-parameter scaling relation between the DEE and system size at the critical point has been derived for the first time, which successfully obtains the critical exponent via data collapse. Furthermore, we find that the EE peaks at the(emergent) symmetryenhanced first-order transition, reflecting higher symmetry breaking. This work provides a new paradigm for quantum many-body research from the perspective of EE and DEE.
基金supported by the National Natural Science Foundation of China (Grant Nos.12274273and 12450402)the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0302101)。
文摘The rapid advancements of ultrafast intense laser technology have opened new avenues for investigating entanglement in laser-induced systems. However, the application of these advances in quantum technology requires a reliable and universally applicable method for enhancing and regulating entanglement. Here we demonstrate how a few-cycle intense laser field can significantly enhance the degree of entanglement compared to its multi-cycle counterpart, using the example of electron–electron entanglement of orbital angular momentum(OAM) states in recollision-excitation non-sequential double ionization of Ar atoms. By confining the ionization dynamics to a specific narrow time window, the few-cycle pulse purifies the electron trajectories, thereby ensuring high coherence between entangled OAM channels and enhancing entanglement. Furthermore, the degree of entanglement can be efficiently modulated by varying the carrier envelope phase of the few-cycle laser pulse, which is achieved by altering the population across OAM channels. Optimizing coherence through electron trajectory purification with a designed specific temporal waveform of laser field provides a general pathway for enhancing entanglement in laser-induced systems.
基金supported by the National Key R&D Program of China(Grant No.2022YFB3203400)the National Natural Science Foundation of China(Grant No.61901420)Fundamental Research Program of Shanxi Province(Grant No.20230302121116)。
文摘Hybrid entangled states are crucial in quantum physics,offering significant benefits for hybrid quantum communication and quantum computation,and then the conversion of hybrid entangled states is equally critical.This paper presents two novel schemes,that is,one converts the two-qubit hybrid Knill–Laflamme–Milburn(KLM)entangled state into Bell states and the other one transforms the three-qubit hybrid KLM state into Greenberger–Horne–Zeilinger(GHZ)states assisted by error-predicted and parity-discriminated devices.Importantly,the integration of single photon detectors into the parity-discriminated device enhances predictive capabilities,mitigates potential failures,and facilitates seamless interaction between the nitrogen-vacancy center and photons,so the two protocols operate in an error-predicted way,improving the experimental feasibility.Additionally,our schemes demonstrate robust fidelities(close to 1)and efficiencies,indicating their feasibility with existing technology.
基金the support of the International Young Scientist Fellowship of the Institute of Physics,Chinese Academy of Sciences (Grant No.202407)supported by the Innovation Program for Quantum Science and Technology (Grant No.2024ZD0301700)+1 种基金the start-up grant at IOP-CAS.ZXL is supported by the Beijing Natural Science Foundation (Grant No.JR25007)the National Natural Science Foundation of China (Grants No.12347107and 12474146)。
文摘Entanglement asymmetry(EA) has emerged as a powerful tool for characterizing symmetry breaking in quantum many-body systems. In this Letter, we explore how symmetry is dynamically broken through the lens of EA in two distinct scenarios: a non-symmetric Hamiltonian quench and a non-symmetric random quantum circuit, with a particular focus on U(1) symmetry. In the former case, symmetry remains broken in the subsystem at late times, whereas in the latter case, the symmetry is initially broken and subsequently restored, consistent with the principles of quantum thermalization. Notably, the growth of EA exhibits unexpected overshooting behavior at early times in both contexts, contrasting with the behavior of charge variance. We also consider dynamics of non-symmetric initial states under the symmetry-breaking evolution. Due to the competition of symmetry-breaking in both the initial state and Hamiltonian, the early-time EA can increase and decrease, while quantum Mpemba effects remain evident despite the weak symmetry-breaking in both settings.
文摘In this second part of a study about quantum field oscillators with sub-oscillators and semi-quanta (IQuO), it is possible to show that in the initial phase of an interaction between two particles a no-dynamic process of reduction from a non-local to a local state takes place which cannot be described by Hamiltonian. We then describe the coupling of two IQuO of different particle-fields either at one point in space or at two distant points via an intermediary chain of coupled IQuO. The first aspect provides an understanding of the basic processes of creating and annihilating a pair. The second aspect describes the behaviour of two electrically charged particles through a process of phase shifts between the respective IQuO chains (CF1, CF2) implemented in a quantum entanglement via an intermediary chain (CB) of IQuO that originates changes in the direction of the two (CF1, CF2) distance-correlated ones. Thus, the semi-quanta structure of an IQuO and quantum entanglement identify the origin of the empirical law of attraction and repulsion between two electric charges.
基金supported through computational resources of HPC-MARWAN(www.marwan.ma/hpc)provided by CNRST,Rabat,Morocco。
文摘A classification of multipartite entanglement is introduced for pure and mixed states.The classification is based on the distribution of entanglement between the qubits of a given system,with a mathematical framework used to characterize fully entangled states.Then we use current machine learning and deep learning techniques to automatically classify a random state of two,three,and four qubits without the need to compute the amount of the different types of entanglement in each run;rather this is done only in the learning process.The technique shows high,near-perfect,accuracy in the case of pure states.As expected,this accuracy drops,more or less,when dealing with mixed states and when increasing the number of parties involved.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12175106 and 92365110)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(Grant No.KYCX23-1028)。
文摘Hybrid entangled states(HESs),which involve different particles with various degrees of freedom,have garnered significant attention and been applied in a wide range of quantum technologies.However,similar to other categories of entanglement,maximally HESs inevitably degrade to mixed states due to the environmental noise and operational imperfections.To address the degradation problem,measurement-based entanglement purification offers a feasible and robust solution alternative to conventional gate-based purification methods.In this paper,we propose a measurement-based hybrid entanglement purification protocol(MB-HEPP)for a certain kind of HES which consists of polarization photons and coherent states.We extend our methodology to several conditions,such as the multi-copy and multi-party scenarios,and the photon-loss condition.Compared with previous HEPPs,this protocol has several advantages.First,it does not depend on post-selection and the purified HESs can be retained for further application.Second,it does not require the Bell state measurement,but only uses the parity check with conventional linear optical elements,which makes it have the higher success probability and more feasible.Our MB-HEPP has potential applications in future heterogeneous quantum networks.
基金Project supported by the National Natural Science Foundation of China(Grant No.62071363)the Key Research and Development Projects of Shaanxi Province,China(Grant No.2021LLRH-06)。
文摘We present a quantum ranging protocol that overcomes photon-loss limitations using optimized partially frequencyentangled states.By establishing the fundamental relationship between the degree of entanglement,channel transmission efficiency and measurement precision,we demonstrate superclassical timing resolution in both lossless and lossy regimes.Theoretical analysis and numerical simulations reveal that,under a lossless channel,the precision gain increases with the degree of entanglement,approaching the Heisenberg limit.Importantly,in lossy channels,the precision gain is significantly influenced by both the channel transmission efficiency and the degree of entanglement.For transmission efficiencies above50%,the proposed method provides up to 1.5 times the precision gain of classical methods when entanglement parameters are optimized.Moreover,by optimizing intra-group and inter-group covariances in the multi-structured entangled state,we achieve substantial precision gains even at low transmission efficiencies(~30%),demonstrating its robustness against loss.This study resolves the critical trade-off between entanglement-enhanced precision and loss-induced information degradation.Future implementation could extend to satellite-based quantum positioning,remote sensing,quantum illumination,and other fields that require high-precision ranging in lossy environments.The protocol establishes a universal framework for loss-tolerant quantum metrology,advancing the practical deployment of quantum-enhanced sensing in real-world applications.
基金supported by the National Key Research&Development Program of China(grant no.2022YFC3500503)the National Natural Science Foundation of China(grant nos.62227807,12374171,12004034,62402041)+2 种基金the Beijing Institute of Technology Research Fund Program for Young Scholars,Chinathe Fundamental Research Funds for the Central Universities(grant nos.2024CX06060)Beijing Youth Talent Lifting Project.
文摘Due to their high mechanical compliance and excellent biocompatibility,conductive hydrogels exhibit significant potential for applications in flexible electronics.However,as the demand for high sensitivity,superior mechanical properties,and strong adhesion performance continues to grow,many conventional fabrication methods remain complex and costly.Herein,we propose a simple and efficient strategy to construct an entangled network hydrogel through a liquid-metal-induced cross-linking reaction,hydrogel demonstrates outstanding properties,including exceptional stretchability(1643%),high tensile strength(366.54 kPa),toughness(350.2 kJ m^(−3)),and relatively low mechanical hysteresis.The hydrogel exhibits long-term stable reusable adhesion(104 kPa),enabling conformal and stable adhesion to human skin.This capability allows it to effectively capture high-quality epidermal electrophysiological signals with high signal-to-noise ratio(25.2 dB)and low impedance(310 ohms).Furthermore,by integrating advanced machine learning algorithms,achieving an attention classification accuracy of 91.38%,which will significantly impact fields like education,healthcare,and artificial intelligence.
基金supported by the Department of Education of Liaoning Province(Grant Nos.LJKZ1015,LJ2020005,LJKZZ20220120)the Natural Science Foundation of Liaoning Province(Grant Nos.2020-BS-234,2021-MS-317,2022-MS-372)the Program of Liaoning Bai Qian Wan Talents Program(Grant No.2021921096)。
文摘Conversion between different types of entangled states is an interesting problem in quantum mechanics.But research on the conversion between the Greenberger-Horne-Zeilinger(GHZ)state and Knill-Laflamme-Milburn(KLM)state in an atomic system has not been reported.In this paper,we propose a scheme to realize the interconversion(one-step)between the GHZ state and KLM state with Rydberg atoms.By utilizing Rydberg-mediated interactions,we simplify the system.By combining a Lie-transform-based pulse design,the evolution path is built up to realize interconversion of the GHZ state and KLM state.The numerical simulation result shows that the present scheme is robust against decoherence and operational imperfection.
文摘A parametrization of density matrices of ddimensions in terms of the raising J+and lowering J−angular momentum operators is established together with an implicit connection with the generalized Bloch-GellMann parameters. A general expression for the density matrix of the composite system of angular momenta j1and j2is obtained. In this matrix representation violations of the Bell-Clauser-Horne-Shimony-Holt inequalities are established for the X-states of a qubit-qubit, pure and mixed, composite system, as well as for a qubit-qutrit density matrix. In both cases maximal violation of the Bell inequalities can be reached, i.e., the Cirel’son limit. A correlation between the entanglement measure and a strong violation of the Bell factor is also given. For the qubit-qutrit composite system a time-dependent convex combination of the density matrix of the eigenstates of a two-particle Hamiltonian system is used to determine periodic maximal violations of the Bell’s inequality.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12204440)Fundamental Research Program of Shanxi Province (Grant Nos. 20210302123063 and 202103021223184)。
文摘We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system comprises an optical cavity, a two-level atomic ensemble and a mechanical resonator that possesses Duffing nonlinearity. The interaction between these components is mediated by the cavity mode, which is driven by an external laser. Our findings indicate that optimizing the coupling strengths between photons and phonons, as well as between atoms and the cavity,leads to maximal entanglement and EPR steering. The amplitude of the driving laser plays a pivotal role in enhancing the coupling between photons and phonons, and the system maintains robust entanglement and EPR steering even under high dissipation, thereby mitigating the constraints on initial conditions and parameter precision. Remarkably, the Duffing nonlinearity enhances the system's resistance to thermal noise, ensuring its stability and entanglement protection. Our analysis of EPR steering conditions reveals that the party with lower dissipation exhibits superior stability and a propensity to steer the party with higher dissipation. These discoveries offer novel perspectives for advancing quantum information processing and communication technologies.
