Relaxation processes in quantum systems coupled to external environments represent one of the most fundamental nonequilibrium phenomena in condensed matter physics.The Lindblad master equation provides a powerful fram...Relaxation processes in quantum systems coupled to external environments represent one of the most fundamental nonequilibrium phenomena in condensed matter physics.The Lindblad master equation provides a powerful framework for characterizing such open quantum dynamics.In this work,we systematically investigate how different types of quantum jump operators and system geometries influence the Liouvillian gap and the properties of the nonequilibrium steady state(NESS)in finite-size systems.We demonstrate that,due to the intricate structure of the Liouvillian superoperator,multiple NESSs with unphysical characteristics can emerge.The physically meaningful steady state must instead be understood as a superposition of these NESSs that collectively satisfy the required physical constraints.Furthermore,we find that the Liouvillian gap does not necessarily increase monotonically with the system-environment coupling strength.Instead,it can exhibit a nontrivial peak structure,corresponding to a minimum in the relaxation time.The magnitude of this peak is closely related to the symmetry properties of the system.Our results provide a deeper understanding of nonequilibrium behavior in finite quantum systems and offer new insights into the design and control of open quantum dynamics.展开更多
In this paper,we introduce certain subclasses of harmonic univalent functions associated with the Janowski functions,which are defined by using generalized(p,q)-post quantum calculus operators.Sufficient coefficient c...In this paper,we introduce certain subclasses of harmonic univalent functions associated with the Janowski functions,which are defined by using generalized(p,q)-post quantum calculus operators.Sufficient coefficient conditions,extreme points,distortion bounds and partial sums properties for the functions belonging to the subclasses are obtained.展开更多
We introduce the quantum Hadamard operator in continuum state vector space and find that it can be decomposed into a single-mode squeezing operator and a position-momentum mutual transform operator. The two-mode Hadam...We introduce the quantum Hadamard operator in continuum state vector space and find that it can be decomposed into a single-mode squeezing operator and a position-momentum mutual transform operator. The two-mode Hadamard operator in bipartite entangled state representation is also introduced, which involves the two-mode squeezing operator and [η〉 ←→｜ξ〉 mutual transformation operator, where [η〉 and ｜ξ〉 are mutual conjugate entangled states. All the discussions are proceeded by virtue of the IWOP technique.展开更多
We derive normally ordered quantum gate operators for continuum variables by mapping classical transforms onto Fock space. Successive gate operations can be treated in a unified way that is using the technique of inte...We derive normally ordered quantum gate operators for continuum variables by mapping classical transforms onto Fock space. Successive gate operations can be treated in a unified way that is using the technique of integration within an ordered product of operators.展开更多
The quantum alternating operator ansatz algorithm(QAOA+)is widely used for constrained combinatorial optimization problems(CCOPs)due to its ability to construct feasible solution spaces.In this paper,we propose a prog...The quantum alternating operator ansatz algorithm(QAOA+)is widely used for constrained combinatorial optimization problems(CCOPs)due to its ability to construct feasible solution spaces.In this paper,we propose a progressive quantum algorithm(PQA)to reduce qubit requirements for QAOA+in solving the maximum independent set(MIS)problem.PQA iteratively constructs a subgraph likely to include the MIS solution of the original graph and solves the problem on it to approximate the global solution.Specifically,PQA starts with a small-scale subgraph and progressively expands its graph size utilizing heuristic expansion strategies.After each expansion,PQA solves the MIS problem on the newly generated subgraph using QAOA+.In each run,PQA repeats the expansion and solving process until a predefined stopping condition is reached.Simulation results show that PQA achieves an approximation ratio of 0.95 using only 5.57%(2.17%)of the qubits and 17.59%(6.43%)of the runtime compared with directly solving the original problem with QAOA+on Erd?s-Rényi(3-regular)graphs,highlighting the efficiency and scalability of PQA.展开更多
This report presents a second version of the Interactive Quantum Development Environment (IQDE), virtualized parallel simulation platform for optimized testing of quantum software. IQDE is an interactive quantum simul...This report presents a second version of the Interactive Quantum Development Environment (IQDE), virtualized parallel simulation platform for optimized testing of quantum software. IQDE is an interactive quantum simulator intended for implementation of a classical computer that can simulate numerous controlled and time-dependent operations. The research presents different relations between the operations that can be typically simulated. The virtualized simulation platform carries out numerous single-node and multi-node optimizations, including vectorization, parallelization, cache sharing, as well as overlapping of the computations with the communication. A common strategy for modeling for shared memory is implemented, as well as realistic parallel simulation with cluster management of the parallelization. А detailed analysis of the implementation is performed in order to be demonstrated that the simulator achieves good operation and high efficiency of the hardware, which is only limited by the available memory and the bandwidth of the machine.展开更多
This report describes a fundamental model of a quantum circuit for finding complex eigenvalues of Hamiltonian matrices on the quantum computers through the use of an iteration algorithm for estimation of the phase. In...This report describes a fundamental model of a quantum circuit for finding complex eigenvalues of Hamiltonian matrices on the quantum computers through the use of an iteration algorithm for estimation of the phase. In addition to this, we demonstrate the use of the model for simulating the resonant states for quantum systems.展开更多
We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. Fo...We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. For a 2-mm-long and 10-μm-wide laser coated with high-reflectivity on the rear facet, more than 170mW of output power is obtained at 20℃ with a threshold power consumption of 2.4 W, corresponding to 30mW with a threshold power consumption of 3.9 W at 90℃. Robust single-mode emission with a side-mode suppression ratio above 25 dB is continuously tunable by the heat sink temperature or injection current.展开更多
We report an external cavity quantum cascade laser （EC-QCL） operating near 6.9μm using the Littman Metcalf configuration. The EC-QCL works in a pulsed mode and can be tuned continuously from 1340 to 1640cm^-1 by on...We report an external cavity quantum cascade laser （EC-QCL） operating near 6.9μm using the Littman Metcalf configuration. The EC-QCL works in a pulsed mode and can be tuned continuously from 1340 to 1640cm^-1 by only tilting the tuning mirror. The fine tuning ability of the EC-QCL is demonstrated by measuring the absorption spectrum of water in the ambient air with a lock-in amplifier.展开更多
We present two protocols for the controlled remote implementation of quantum operations between three-party high-dimensional systems. Firstly, the controlled teleportation of an arbitrary unitary operation by bidirect...We present two protocols for the controlled remote implementation of quantum operations between three-party high-dimensional systems. Firstly, the controlled teleportation of an arbitrary unitary operation by bidirectional quantum state teleportaion （BQST） with high-dimensional systems is considered. Then, instead of using the BQST method, a protocol for controlled remote implementation of partially unknown operations belonging to some restricted sets in high-dimensional systems is proposed. It is shown that, in these protocols, if and only if the controller would like to help the sender with the remote operations, the controlled remote implementation of quantum operations for high-dimensional systems can be completed.展开更多
A new dynamic model identification method is developed for continuous-time series analysis and forward prediction applications. The quantum of data is defined over moving time intervals in sliding window coordinates f...A new dynamic model identification method is developed for continuous-time series analysis and forward prediction applications. The quantum of data is defined over moving time intervals in sliding window coordinates for compressing the size of stored data while retaining the resolution of information. Quantum vectors are introduced as the basis of a linear space for defining a Dynamic Quantum Operator (DQO) model of the system defined by its data stream. The transport of the quantum of compressed data is modeled between the time interval bins during the movement of the sliding time window. The DQO model is identified from the samples of the real-time flow of data over the sliding time window. A least-square-fit identification method is used for evaluating the parameters of the quantum operator model, utilizing the repeated use of the sampled data through a number of time steps. The method is tested to analyze, and forward-predict air temperature variations accessed from weather data as well as methane concentration variations obtained from measurements of an operating mine. The results show efficient forward prediction capabilities, surpassing those using neural networks and other methods for the same task.展开更多
We make comments on the conclusions of the paper:'Compare Quantum Operation Sensitivity for DifferentDistance Measures' [Commun.Theor.Phys.53 (2010)635],and give a physical example to describe the non-equivale...We make comments on the conclusions of the paper:'Compare Quantum Operation Sensitivity for DifferentDistance Measures' [Commun.Theor.Phys.53 (2010)635],and give a physical example to describe the non-equivalenceof the fidelity and the trace distance.We prove that the fidelity is not more sensitive to a quantum operation than thetrace distance.展开更多
By constructing the recovery operations of the protocol of remote implementation of partially unknownquantum operation of two qubits[An-Min Wang:Phys.Rev.A 74(2006)032317]with two-qubit Cnot gate and singlequbit logic...By constructing the recovery operations of the protocol of remote implementation of partially unknownquantum operation of two qubits[An-Min Wang:Phys.Rev.A 74(2006)032317]with two-qubit Cnot gate and singlequbit logic gates,we present a scheme to implement it in cavity QED.Long-lived Rydberg atoms are used as qubits,and the interaction between the atoms and the field of cavity is a nonresonant one.Finally,we analyze the experimentalfeasibility of this scheme.展开更多
In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may...In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may explain in some sense why fidelity is so useful in quantum information theory.展开更多
For classical transformation （q1,q2） → （Aq1 ＋ Bq2, Cq1 ＋ Dq2）, where AD - CB ≠ 1, we find its quantum mechanical image by using LDU decomposition of the matrix （A B C D ）. The explicit operators L, D, and U ...For classical transformation （q1,q2） → （Aq1 ＋ Bq2, Cq1 ＋ Dq2）, where AD - CB ≠ 1, we find its quantum mechanical image by using LDU decomposition of the matrix （A B C D ）. The explicit operators L, D, and U axe derived and their physical meaning is revealed, this also provides a new way for disentangling some exponential operators.展开更多
A high-power and high-effciency GaAs/A1GaAs-based terahertz （THz） quantum cascade laser structure emitting at 3.3 THz is presented. The structure is based on a hybrid bound-to-continuum transition and resonant-phono...A high-power and high-effciency GaAs/A1GaAs-based terahertz （THz） quantum cascade laser structure emitting at 3.3 THz is presented. The structure is based on a hybrid bound-to-continuum transition and resonant-phonon extraction active region combined with a semi-insulating surface-plasmon waveguide. By optimizing material structure and device processing, the peak optical output power of 758mW with a threshold current density of 120 A/cm2 and a wall-plug effciency of 0.92% at 10K and 404mW at 77K are obtained in pulsed operation. The maximum operating temperature is as high as llS K. In the cw mode, a record optical output power of 160roW with a threshold current density of 178A/cm2 and a wall-plug efficiency of 1.32% is achieved at 1OK.展开更多
Our concern is to investigate controlled remote implementation of partially unknown operations with multiple layers.We first propose a scheme to realize the remote implementation of singlequbit operations belonging to...Our concern is to investigate controlled remote implementation of partially unknown operations with multiple layers.We first propose a scheme to realize the remote implementation of singlequbit operations belonging to the restricted sets.Then,the proposed scheme is extended to the case of single-qudit operations.As long as the controller and the higher-layer senders consent,the receiver can restore the desired state remotely operated by the sender.It is worth mentioning that the recovery operation is deduced by general formulas which clearly reveal the relationship with the measurement outcomes.For the sake of clarity,two specific examples with two levels are given respectively.In addition,we discuss the influence of amplitude-damping noise and utilize weak measurement and measurement reversal to effectively resist noise.展开更多
Quantum walks with one-dimensional translational symmetry are important for quantum algorithms,where the speed-up of the diffusion speed can be reached if long-range couplings are added.Our work studies a scheme of a ...Quantum walks with one-dimensional translational symmetry are important for quantum algorithms,where the speed-up of the diffusion speed can be reached if long-range couplings are added.Our work studies a scheme of a ring under the strong resonant modulation that can support a discrete-time quantum walk including coherent multiple long-range translations in a natural way along the synthetic frequency dimension.These multiple translation paths are added in a coherent way,which makes the walker evolve under the topological band.Therein,not only the fast diffusion speed is expected,but more importantly,we find that single quantum gate operations can be performed in the quasi-momentum space.In particular,we show the arbitrary single-qubit state preparation and an example of CNOT two-qubit gate with only one time step,dramatically increasing quantum algorithms.Our study uses the modulated ring to provide fast quantum gate operations based on coherent multiple path quantum walk,which may provide unique designs for efficient quantum operations on photonic chips.展开更多
Complex numbers are theoretically proved and experimentally confirmed as necessary in quantum mechanics and quantum information,and a resource theory of imaginarity of quantum states has been established.In this work,...Complex numbers are theoretically proved and experimentally confirmed as necessary in quantum mechanics and quantum information,and a resource theory of imaginarity of quantum states has been established.In this work,we establish a framework to quantify the imaginarity of quantum operations from the perspective of the ability to create or detect imaginarity,following the idea by Theurer et al.(Phys.Rev.Lett.122,190405(2019))used in coherence theory.We introduce two types of imaginarity measures of quantum operations based on the norm and the weight,investigate their properties and relations,derive the analytical formulas of the measure under the trace norm for qubit unitary operations,and present some applications in the tasks of channel discrimination and the entanglement-assisted exclusion.The results provide new insights into the imaginarity of operations and deepen our understanding of dynamical imaginarity.展开更多
The entanglement, one of the central mysteries of the quantum mechanics, plays a significant role in a variety of applications of the quantum information theory. A natural question in theoretical and experimental impo...The entanglement, one of the central mysteries of the quantum mechanics, plays a significant role in a variety of applications of the quantum information theory. A natural question in theoretical and experimental importance is whether it is possible to detect a universal entanglement without full diagnostics. The diagnostics relies on a set of quantum trajectories and their records from measurements. This model reflects the probability that each of the measurements may be damaged from interference and decoherence, and may also be associated with recording of continuous signals for an end-time period. The goal is then to retrieve the quantum state such as it had been in the beginning of this measurement process. The proposed solution relies on explicit expression of the probability function through effective matrices contained in the quantum approximation and solutions of ad-joint quantum filters. In this article, we prove а no-go theorem, which outlines this possibility for non-adaptive schemes, which use only single-copy measurements. We also examine in detail а previously conducted experiment, for which it is claimed that detects the entanglement of two-qubit states through adaptive single-copy measurements without full diagnostics. With the conduct of the experiment and the analysis of the data, we demonstrate that the information collected is really sufficient to reconstruct the state. These results reveal a fundamental limit of the single-copy measurements upon the entanglement detection, and provide a common framework for learning the detection of other interesting properties of the quantum states, such as the positivity of partial transposition and the k-symmetric-extendibility.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12275193 and11975166)。
文摘Relaxation processes in quantum systems coupled to external environments represent one of the most fundamental nonequilibrium phenomena in condensed matter physics.The Lindblad master equation provides a powerful framework for characterizing such open quantum dynamics.In this work,we systematically investigate how different types of quantum jump operators and system geometries influence the Liouvillian gap and the properties of the nonequilibrium steady state(NESS)in finite-size systems.We demonstrate that,due to the intricate structure of the Liouvillian superoperator,multiple NESSs with unphysical characteristics can emerge.The physically meaningful steady state must instead be understood as a superposition of these NESSs that collectively satisfy the required physical constraints.Furthermore,we find that the Liouvillian gap does not necessarily increase monotonically with the system-environment coupling strength.Instead,it can exhibit a nontrivial peak structure,corresponding to a minimum in the relaxation time.The magnitude of this peak is closely related to the symmetry properties of the system.Our results provide a deeper understanding of nonequilibrium behavior in finite quantum systems and offer new insights into the design and control of open quantum dynamics.
基金Supported by the Natural Science Foundation of Inner Mongolia Autonomous Region(Grant No.2019MS01023)the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region(Grant Nos.NJZZ19209,NJZY20198).
文摘In this paper,we introduce certain subclasses of harmonic univalent functions associated with the Janowski functions,which are defined by using generalized(p,q)-post quantum calculus operators.Sufficient coefficient conditions,extreme points,distortion bounds and partial sums properties for the functions belonging to the subclasses are obtained.
基金The project supported by National Natural Science Foundation of China under Grant No.10475056
文摘We introduce the quantum Hadamard operator in continuum state vector space and find that it can be decomposed into a single-mode squeezing operator and a position-momentum mutual transform operator. The two-mode Hadamard operator in bipartite entangled state representation is also introduced, which involves the two-mode squeezing operator and [η〉 ←→｜ξ〉 mutual transformation operator, where [η〉 and ｜ξ〉 are mutual conjugate entangled states. All the discussions are proceeded by virtue of the IWOP technique.
文摘We derive normally ordered quantum gate operators for continuum variables by mapping classical transforms onto Fock space. Successive gate operations can be treated in a unified way that is using the technique of integration within an ordered product of operators.
基金supported by the National Natural Science Foundation of China(Grant Nos.62371069,62372048,and 62272056)BUPT Excellent Ph.D.Students Foundation(Grant No.CX2023123)。
文摘The quantum alternating operator ansatz algorithm(QAOA+)is widely used for constrained combinatorial optimization problems(CCOPs)due to its ability to construct feasible solution spaces.In this paper,we propose a progressive quantum algorithm(PQA)to reduce qubit requirements for QAOA+in solving the maximum independent set(MIS)problem.PQA iteratively constructs a subgraph likely to include the MIS solution of the original graph and solves the problem on it to approximate the global solution.Specifically,PQA starts with a small-scale subgraph and progressively expands its graph size utilizing heuristic expansion strategies.After each expansion,PQA solves the MIS problem on the newly generated subgraph using QAOA+.In each run,PQA repeats the expansion and solving process until a predefined stopping condition is reached.Simulation results show that PQA achieves an approximation ratio of 0.95 using only 5.57%(2.17%)of the qubits and 17.59%(6.43%)of the runtime compared with directly solving the original problem with QAOA+on Erd?s-Rényi(3-regular)graphs,highlighting the efficiency and scalability of PQA.
文摘This report presents a second version of the Interactive Quantum Development Environment (IQDE), virtualized parallel simulation platform for optimized testing of quantum software. IQDE is an interactive quantum simulator intended for implementation of a classical computer that can simulate numerous controlled and time-dependent operations. The research presents different relations between the operations that can be typically simulated. The virtualized simulation platform carries out numerous single-node and multi-node optimizations, including vectorization, parallelization, cache sharing, as well as overlapping of the computations with the communication. A common strategy for modeling for shared memory is implemented, as well as realistic parallel simulation with cluster management of the parallelization. А detailed analysis of the implementation is performed in order to be demonstrated that the simulator achieves good operation and high efficiency of the hardware, which is only limited by the available memory and the bandwidth of the machine.
文摘This report describes a fundamental model of a quantum circuit for finding complex eigenvalues of Hamiltonian matrices on the quantum computers through the use of an iteration algorithm for estimation of the phase. In addition to this, we demonstrate the use of the model for simulating the resonant states for quantum systems.
基金Supported by the National Basic Research Program of China under Grant No 2013CB632801the National Key Research and Development Program under Grant No 2016YFB0402303+2 种基金the National Natural Science Foundation of China under Grant Nos61435014,61627822,61574136 and 61306058the Key Projects of Chinese Academy of Sciences under Grant No ZDRW-XH-2016-4the Beijing Natural Science Foundation under Grant No 4162060
文摘We report on the design and fabrication of λ-7.2μm distributed feedback quantum cascade lasers lot very high temperature cw operation and low electrical power consumption. The cw operation is reported above 90℃. For a 2-mm-long and 10-μm-wide laser coated with high-reflectivity on the rear facet, more than 170mW of output power is obtained at 20℃ with a threshold power consumption of 2.4 W, corresponding to 30mW with a threshold power consumption of 3.9 W at 90℃. Robust single-mode emission with a side-mode suppression ratio above 25 dB is continuously tunable by the heat sink temperature or injection current.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174098 and 11574107the SelfDetermined Research Funds of Central China Normal University under Grant No CCNU15A02034
文摘We report an external cavity quantum cascade laser （EC-QCL） operating near 6.9μm using the Littman Metcalf configuration. The EC-QCL works in a pulsed mode and can be tuned continuously from 1340 to 1640cm^-1 by only tilting the tuning mirror. The fine tuning ability of the EC-QCL is demonstrated by measuring the absorption spectrum of water in the ambient air with a lock-in amplifier.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11074088)
文摘We present two protocols for the controlled remote implementation of quantum operations between three-party high-dimensional systems. Firstly, the controlled teleportation of an arbitrary unitary operation by bidirectional quantum state teleportaion （BQST） with high-dimensional systems is considered. Then, instead of using the BQST method, a protocol for controlled remote implementation of partially unknown operations belonging to some restricted sets in high-dimensional systems is proposed. It is shown that, in these protocols, if and only if the controller would like to help the sender with the remote operations, the controlled remote implementation of quantum operations for high-dimensional systems can be completed.
文摘A new dynamic model identification method is developed for continuous-time series analysis and forward prediction applications. The quantum of data is defined over moving time intervals in sliding window coordinates for compressing the size of stored data while retaining the resolution of information. Quantum vectors are introduced as the basis of a linear space for defining a Dynamic Quantum Operator (DQO) model of the system defined by its data stream. The transport of the quantum of compressed data is modeled between the time interval bins during the movement of the sliding time window. The DQO model is identified from the samples of the real-time flow of data over the sliding time window. A least-square-fit identification method is used for evaluating the parameters of the quantum operator model, utilizing the repeated use of the sampled data through a number of time steps. The method is tested to analyze, and forward-predict air temperature variations accessed from weather data as well as methane concentration variations obtained from measurements of an operating mine. The results show efficient forward prediction capabilities, surpassing those using neural networks and other methods for the same task.
基金Supported by the Natural Science Foundation of Shandong Province under Grant No. ZR2009AM019
文摘We make comments on the conclusions of the paper:'Compare Quantum Operation Sensitivity for DifferentDistance Measures' [Commun.Theor.Phys.53 (2010)635],and give a physical example to describe the non-equivalenceof the fidelity and the trace distance.We prove that the fidelity is not more sensitive to a quantum operation than thetrace distance.
基金supported by the National Fundamental Research Program of China under Grant No.2001CB309310partially by National Natural Science Foundation of China under Grant No.60573008
文摘By constructing the recovery operations of the protocol of remote implementation of partially unknownquantum operation of two qubits[An-Min Wang:Phys.Rev.A 74(2006)032317]with two-qubit Cnot gate and singlequbit logic gates,we present a scheme to implement it in cavity QED.Long-lived Rydberg atoms are used as qubits,and the interaction between the atoms and the field of cavity is a nonresonant one.Finally,we analyze the experimentalfeasibility of this scheme.
基金Supported by National Natural Science Foundation of China under Grant No. 10901103the New Teacher Foundation of Ministry of Education of China under Grant No. 20070248087Supported by a Grant of Science and Technology Commission of Shanghai Municipality (STCSM No. 09XD1402500)
文摘In this paper, we compare the quantum operation sensitivity for different distance measures. We find that, among all usual distance measures, Bures fidelity is more sensitive to quantum operation than others. This may explain in some sense why fidelity is so useful in quantum information theory.
基金Supported by the President Foundation of Chinese Academy of Science and Specialized Research Fund for the Doctorial Progress of Higher Education under Grant No.20070358009
文摘For classical transformation （q1,q2） → （Aq1 ＋ Bq2, Cq1 ＋ Dq2）, where AD - CB ≠ 1, we find its quantum mechanical image by using LDU decomposition of the matrix （A B C D ）. The explicit operators L, D, and U axe derived and their physical meaning is revealed, this also provides a new way for disentangling some exponential operators.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB339803 and 2013CB632801the National Natural Science Foundation of China under Grant No 61376051
文摘A high-power and high-effciency GaAs/A1GaAs-based terahertz （THz） quantum cascade laser structure emitting at 3.3 THz is presented. The structure is based on a hybrid bound-to-continuum transition and resonant-phonon extraction active region combined with a semi-insulating surface-plasmon waveguide. By optimizing material structure and device processing, the peak optical output power of 758mW with a threshold current density of 120 A/cm2 and a wall-plug effciency of 0.92% at 10K and 404mW at 77K are obtained in pulsed operation. The maximum operating temperature is as high as llS K. In the cw mode, a record optical output power of 160roW with a threshold current density of 178A/cm2 and a wall-plug efficiency of 1.32% is achieved at 1OK.
基金supported by the National Natural Science Foundation of China(Grant Nos.62172341,12071132)the Natural Science Foundation of Henan Province of China(Grant No.242300420276)the Joint Fund of Henan Province Science and Technology R&D Program(Grant No.225200810032)。
文摘Our concern is to investigate controlled remote implementation of partially unknown operations with multiple layers.We first propose a scheme to realize the remote implementation of singlequbit operations belonging to the restricted sets.Then,the proposed scheme is extended to the case of single-qudit operations.As long as the controller and the higher-layer senders consent,the receiver can restore the desired state remotely operated by the sender.It is worth mentioning that the recovery operation is deduced by general formulas which clearly reveal the relationship with the measurement outcomes.For the sake of clarity,two specific examples with two levels are given respectively.In addition,we discuss the influence of amplitude-damping noise and utilize weak measurement and measurement reversal to effectively resist noise.
基金supported by the National Key Research and Development Program of China(no.2023YFA1407200)the National Natural Science Foundation of China(12122407,12192252,and 12204304)the China Postdoctoral Science Foundation(2023M742292,GZC20231614).
文摘Quantum walks with one-dimensional translational symmetry are important for quantum algorithms,where the speed-up of the diffusion speed can be reached if long-range couplings are added.Our work studies a scheme of a ring under the strong resonant modulation that can support a discrete-time quantum walk including coherent multiple long-range translations in a natural way along the synthetic frequency dimension.These multiple translation paths are added in a coherent way,which makes the walker evolve under the topological band.Therein,not only the fast diffusion speed is expected,but more importantly,we find that single quantum gate operations can be performed in the quasi-momentum space.In particular,we show the arbitrary single-qubit state preparation and an example of CNOT two-qubit gate with only one time step,dramatically increasing quantum algorithms.Our study uses the modulated ring to provide fast quantum gate operations based on coherent multiple path quantum walk,which may provide unique designs for efficient quantum operations on photonic chips.
基金supported by the National Natural Science Foundation of China(Grant Nos.12561084 and 12161056)the Natural Science Foundation of Jiangxi Province(Grant No.20232ACB211003)。
文摘Complex numbers are theoretically proved and experimentally confirmed as necessary in quantum mechanics and quantum information,and a resource theory of imaginarity of quantum states has been established.In this work,we establish a framework to quantify the imaginarity of quantum operations from the perspective of the ability to create or detect imaginarity,following the idea by Theurer et al.(Phys.Rev.Lett.122,190405(2019))used in coherence theory.We introduce two types of imaginarity measures of quantum operations based on the norm and the weight,investigate their properties and relations,derive the analytical formulas of the measure under the trace norm for qubit unitary operations,and present some applications in the tasks of channel discrimination and the entanglement-assisted exclusion.The results provide new insights into the imaginarity of operations and deepen our understanding of dynamical imaginarity.
文摘The entanglement, one of the central mysteries of the quantum mechanics, plays a significant role in a variety of applications of the quantum information theory. A natural question in theoretical and experimental importance is whether it is possible to detect a universal entanglement without full diagnostics. The diagnostics relies on a set of quantum trajectories and their records from measurements. This model reflects the probability that each of the measurements may be damaged from interference and decoherence, and may also be associated with recording of continuous signals for an end-time period. The goal is then to retrieve the quantum state such as it had been in the beginning of this measurement process. The proposed solution relies on explicit expression of the probability function through effective matrices contained in the quantum approximation and solutions of ad-joint quantum filters. In this article, we prove а no-go theorem, which outlines this possibility for non-adaptive schemes, which use only single-copy measurements. We also examine in detail а previously conducted experiment, for which it is claimed that detects the entanglement of two-qubit states through adaptive single-copy measurements without full diagnostics. With the conduct of the experiment and the analysis of the data, we demonstrate that the information collected is really sufficient to reconstruct the state. These results reveal a fundamental limit of the single-copy measurements upon the entanglement detection, and provide a common framework for learning the detection of other interesting properties of the quantum states, such as the positivity of partial transposition and the k-symmetric-extendibility.
