Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed ...Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed in past few decades,e.g.,the high-precision quantum gate manipulating,the time-reversal harnessing,the high-fidelity state preparation and tomography,the nuclear magnetic resonance(NMR) system offers a unique platform for quantum simulation of many-body physics and high-energy physics.Here,we review the recent experimental progress and discuss the prospects for quantum simulation realized on NMR systems.展开更多
Quantum many-body systems lie at the heart of modern fundamental physics.The study of these systems has revealed a plethora of fascinating phenomena,such as quantum thermalization,many-body localization,and quantum ma...Quantum many-body systems lie at the heart of modern fundamental physics.The study of these systems has revealed a plethora of fascinating phenomena,such as quantum thermalization,many-body localization,and quantum many-body scars.This review provides a comprehensive overview of the recent advances in understanding quantum many-body scars and non-ergodic dynamics in quantum systems on superconducting-circuit platforms,ranging from theoretical mechanisms and effective models to experimental observations.展开更多
Simulating U(1) quantum gauge theories with spatial dimensions greater than one is of great physical significance. Here we propose a simple realization of U(1) gauge theory with Rydberg and Rydberg-dressed atom arrays...Simulating U(1) quantum gauge theories with spatial dimensions greater than one is of great physical significance. Here we propose a simple realization of U(1) gauge theory with Rydberg and Rydberg-dressed atom arrays. Within the experimentally accessible range, we find that the various aspects of the U(1) gauge theory can be well simulated, such as the emergence of topological sectors, incommensurability, and the Rokhsar–Kivelson point that hosts deconfined charge excitations and degenerate topological sectors. Our proposal is promising to implement experimentally and exhibits pronounced quantum dynamics.展开更多
We investigate dynamical quantum phase transitions(DQPTs)in Marko-vian open quantum systems using a variational quantum simulation(VQS)algorithm based on quantum state diffusion(QSD).This approach reformulates the Lin...We investigate dynamical quantum phase transitions(DQPTs)in Marko-vian open quantum systems using a variational quantum simulation(VQS)algorithm based on quantum state diffusion(QSD).This approach reformulates the Lindblad master equation as an ensemble of pure-state trajectories,enabling efficient simula-tion of dissipative quantum dynam-ics with effectively reduced quantum resources.Focusing on the one-di-mensional transverse-field Ising mod-el(TFIM),we simulate quench dynamics under both local and global Lindblad dissipation.The QSD-VQS algorithm accurately captures the nonanalytic cusps in the Loschmidt rate function,and reveals their modulation by dissipation strength and system size.Notably,DQPTs are gradually suppressed under strong local dissipation,while they persist under strong global dissipation due to collective environmental effects.Benchmarking against exact Lindblad solutions confirms the high accuracy and scalability of our method.展开更多
Quantum information processing based on Rydberg atoms emerged as a promising direction two decades ago.Recent experimental and theoretical progresses have shined exciting light on this avenue.In this concise review,we...Quantum information processing based on Rydberg atoms emerged as a promising direction two decades ago.Recent experimental and theoretical progresses have shined exciting light on this avenue.In this concise review,we will briefly introduce the basics of Rydberg atoms and their recent applications in associated areas of neutral atom quantum computation and simulation.We shall also include related discussions on quantum optics with Rydberg atomic ensembles,which are increasingly used to explore quantum computation and quantum simulation with photons.展开更多
Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provi...Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.展开更多
Quantum simulation,as a practical application of noisy quantum computing,has aided the study of exotic quantum matters and the implementation of algorithms that outperform classical approaches.Superconducting qubits,o...Quantum simulation,as a practical application of noisy quantum computing,has aided the study of exotic quantum matters and the implementation of algorithms that outperform classical approaches.Superconducting qubits,one of the most promising candidates for realizing universal quantum computing,possess state-of-the-art features like easy integration of qubits,long coherence time,and high-fidelity single-and two-qubit gates.These characteristics have enabled applications of digital quantum simulation in the fields of physics,chemistry,and computer science.In this review,we first present the basic concepts of superconducting qubits,quantum gates,and digital quantum simulations.We also explore recent progress in digital quantum simulations using superconducting qubits,especially in relation to quantum chemistry,quantum matters,combinatorial optimization,and quantum machine learning.Finally,we address the current challenges of digital quantum simulation with superconducting qubits,and provide a perspective on the future of the field.展开更多
Superconducting quantum bits （qubits） and circuits are the leading candidate for the implementation of solid-state quantum computation. They have also been widely used in a variety of studies of quantum physics, ato...Superconducting quantum bits （qubits） and circuits are the leading candidate for the implementation of solid-state quantum computation. They have also been widely used in a variety of studies of quantum physics, atomic physics, quantum optics, and quantum simulation. In this article, we will present an overview of the basic principles of the superconducting qubits, including the phase, flux, charge, and transmon （Xmon） qubits, and the progress achieved so far concerning the improvements of the device design and quantum coherence property. Experimental studies in various research fields using the superconducting qubits and circuits will be briefly reviewed.展开更多
Quantum simulation has been developed extensively over the past decades,widely applied to different models to explore dynamics in the quantum regime.Rydberg atoms have strong dipole-dipole interactions and interact wi...Quantum simulation has been developed extensively over the past decades,widely applied to different models to explore dynamics in the quantum regime.Rydberg atoms have strong dipole-dipole interactions and interact with each other over a long distance,which makes it straightforward to build many-body interacting quantum systems to simulate specific models.Additionally,neutral atoms are easily manipulated due to their weak interactions.These advantages make Rydberg many-body system an ideal platform to implement quantum simulations.This paper reviews several quantum simulations for different models based on Rydberg many-body systems,including quantum Ising models in one dimension and two dimensions mainly for quantum magnetism,XY model for excitation transport,SSH model for symmetry-protected topological phases,and critical self-organized behaviors in many-body systems.Besides,some challenges and promising directions of quantum simulations based on Rydberg many-body system are discussed in this paper.展开更多
Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of...Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of the absorp- tion and scattering on the transmittance of underwater quantum channel and the maximum secure transmission distance are studied. Considering the roughness of the sea surface, we simulate the performance bounds of CV QKD with different wind speeds using the Monte Carlo method. The results show that even if the secret key rate gradually reduces as the wind speed increases, the maximum transmission distance will not be affected obviously. Compared to the works regarding short-distance underwater optical communication, our research represents a significant step towards establishing secure communication between air platform and submarine vehicle.展开更多
In the past years, great progresses have been made on quantum computation and quantum simulation. Increasing the number of qubits in the quantum processors is expected to be one of the main motivations in the next yea...In the past years, great progresses have been made on quantum computation and quantum simulation. Increasing the number of qubits in the quantum processors is expected to be one of the main motivations in the next years, while noises in manipulation of quantum states may still be inevitable even the precision will improve. For research in this direction, it is necessary to review the available results about noisy multiqubit quantum computation and quantum simulation. The review focuses on multiqubit state generations, quantum computational advantage, and simulating physics of quantum many-body systems. Perspectives of near term noisy intermediate-quantum processors will be discussed.展开更多
Quantum computers promise to solve finite-temperature properties of quantum many-body systems,which is generally challenging for classical computers due to high computational complexities.Here,we report experimental p...Quantum computers promise to solve finite-temperature properties of quantum many-body systems,which is generally challenging for classical computers due to high computational complexities.Here,we report experimental preparations of Gibbs states and excited states of Heisenberg X X and X X Z models by using a 5-qubit programmable superconducting processor.In the experiments,we apply a hybrid quantum–classical algorithm to generate finite temperature states with classical probability models and variational quantum circuits.We reveal that the Hamiltonians can be fully diagonalized with optimized quantum circuits,which enable us to prepare excited states at arbitrary energy density.We demonstrate that the approach has a self-verifying feature and can estimate fundamental thermal observables with a small statistical error.Based on numerical results,we further show that the time complexity of our approach scales polynomially in the number of qubits,revealing its potential in solving large-scale problems.展开更多
Vibrational degrees of freedom in trapped-ion systems have recently been gaining attention as a quantum resource,beyond the role as a mediator for entangling quantum operations on internal degrees of freedom,because o...Vibrational degrees of freedom in trapped-ion systems have recently been gaining attention as a quantum resource,beyond the role as a mediator for entangling quantum operations on internal degrees of freedom,because of the large available Hilbert space.The vibrational modes can be represented as quantum harmonic oscillators and thus offer a Hilbert space with infinite dimensions.Here we review recent theoretical and experimental progress in the coherent manipulation of the vibrational modes,including bosonic encoding schemes in quantum information,reliable and efficient measurement techniques,and quantum operations that allow various quantum simulations and quantum computation algorithms.We describe experiments using the vibrational modes,including the preparation of non-classical states,molecular vibronic sampling,and applications in quantum thermodynamics.We finally discuss the potential prospects and challenges of trapped-ion vibrational-mode quantum information processing.展开更多
Different from the Hermitian case, non-Hermitian(NH) systems have novel properties and strongly relate to open and dissipative quantum systems. In this work, we investigate how to simulate τ-anti-pseudo-Hermitian sys...Different from the Hermitian case, non-Hermitian(NH) systems have novel properties and strongly relate to open and dissipative quantum systems. In this work, we investigate how to simulate τ-anti-pseudo-Hermitian systems in a Hermitian quantum device using linear combinations of unitaries and duality quantum algorithm. Specifying the τ to time-reversal(T) and parity-time-reversal(PT) operators, we construct the two NH two-level systems, design quantum circuits including three qubits, and decide the quantum gates explicitly in detail. We also calculate the success probabilities of the simulation.Experimental implementation can be expected in small quantum simulator.展开更多
This review summarizes the requirement of low temperature conditions in existing experimental approaches to quantum computation and quantum simulation.
Superconducting circuits based on Josephson junctions are regarded as one of the most promising technologies for the implementation of scalable quantum computers.This review presents the basic principles of supercondu...Superconducting circuits based on Josephson junctions are regarded as one of the most promising technologies for the implementation of scalable quantum computers.This review presents the basic principles of superconducting qubits and shows the progress of quantum computing and quantum simulation based on superconducting qubits in recent years.The experimental realization of gate operations,readout,error correction codes,as well as some quantum algorithms are summarized,followed by an introduction of quantum simulation.And then some important applications in fields including condensed matter physics,quantum annealing,and quantum chemistry are discussed.展开更多
Recently,quantum simulation of low-dimensional lattice gauge theories(LGTs)has attracted many interests,which may improve our understanding of strongly correlated quantum many-body systems.Here,we propose an implement...Recently,quantum simulation of low-dimensional lattice gauge theories(LGTs)has attracted many interests,which may improve our understanding of strongly correlated quantum many-body systems.Here,we propose an implementation to approximate Z;LGT on superconducting quantum circuits,where the effective theory is a mixture of a LGT and a gauge-broken term.By using matrix product state based methods,both the ground state properties and quench dynamics are systematically investigated.With an increase of the transverse(electric)field,the system displays a quantum phase transition from a disordered phase to a translational symmetry breaking phase.In the ordered phase,an approximate Gauss law of the Z;LGT emerges in the ground state.Moreover,to shed light on the experiments,we also study the quench dynamics,where there is a dynamical signature of the spontaneous translational symmetry breaking.The spreading of the single particle of matter degree is diffusive under the weak transverse field,while it is ballistic with small velocity for the strong field.Furthermore,due to the emergent Gauss law under the strong transverse field,the matter degree can also exhibit confinement dynamics which leads to a strong suppression of the nearest-neighbor hopping.Our results pave the way for simulating the LGT on superconducting circuits,including the quantum phase transition and quench dynamics.展开更多
Counterdiabatic driving (CD) offers a fast and robust route to manipulate quantum systems, which has widespreadapplications in quantum technologies. However, for higher-dimensional complex systems, the exact CD term i...Counterdiabatic driving (CD) offers a fast and robust route to manipulate quantum systems, which has widespreadapplications in quantum technologies. However, for higher-dimensional complex systems, the exact CD term involving thespectral properties of the system is difficult to calculate and generally takes a complicated form, impeding its experimentalrealization. Recently, many approximate methods have been proposed for designing CD passages in many-body systems. Inthis topical review, we focus on the CD formalism and briefly introduce several experimental constructions and applicationsof approximate CD driving in spin-chain models with nuclear magnetic resonance (NMR) systems.展开更多
The quantum critical regime marks a zone in the phase diagram where quantum fluctuation around the critical point plays a significant role at finite temperatures.While it is of great physical interest,simulation of th...The quantum critical regime marks a zone in the phase diagram where quantum fluctuation around the critical point plays a significant role at finite temperatures.While it is of great physical interest,simulation of the quantum critical regime can be difficult on a classical computer due to its intrinsic complexity.Herein,we propose a variational approach,which minimizes the variational free energy,to simulate and locate the quantum critical regime on a quantum computer.The variational quantum algorithm adopts an ansatz by performing an unitary operator on a product of a single-qubit mixed state,in which the entropy can be analytically obtained from the initial state,and thus the free energy can be accessed conveniently.With numeral simulation,using the one-dimensional Kitaev model as a demonstration we show that the quantum critical regime can be identified by accurately evaluating the temperature crossover line.Moreover,the dependencies of both the correlation length and the phase coherence time with temperature are evaluated for the thermal states.Our work suggests a practical way as well as a first step for investigating quantum critical systems at finite temperatures on quantum devices with few qubits.展开更多
We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of ...We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of the CNFET device and an overall chaotic circuit is pointed out. To verify the effect of temperature variation on the output dynamics of the chaotic circuit, a simulation is performed by employing the CNFET compact model of Wong et al. in HSPICE with a temperature range from -100℃ to 100℃. The obtained results with time series, frequency spectra, and bifurcation diagram from the simulation demonstrate that temperature plays a significant role in the output dynamics of the CNFET-based chaotic circuit. Thus, temperature-related issues should be taken into account while designing a high-quality chaotic generator with high stability.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0308100)the National Natural Science Foundation of China(Grant Nos.12075110,11905099,11605005,11875159,and U1801661)+2 种基金Guangdong Basic and Applied Basic Research Foundation,China(Grant No.2019A1515011383)Science,Technology and Innovation Commission of Shenzhen Municipality(Grant Nos.ZDSYS20170303165926217,JCYJ20170412152620376,and JCYJ20180302174036418)Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2016ZT06D348)。
文摘Thanks to the quantum simulation,more and more problems in quantum mechanics which were previously inaccessible are now open to us.Capitalizing on the state-of-the-art techniques on quantum coherent control developed in past few decades,e.g.,the high-precision quantum gate manipulating,the time-reversal harnessing,the high-fidelity state preparation and tomography,the nuclear magnetic resonance(NMR) system offers a unique platform for quantum simulation of many-body physics and high-energy physics.Here,we review the recent experimental progress and discuss the prospects for quantum simulation realized on NMR systems.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LD25A050002)the National Natural Science Foundation of China(No.12375021)the National Key Research and Development Program of China(No.2022YFA1404203).
文摘Quantum many-body systems lie at the heart of modern fundamental physics.The study of these systems has revealed a plethora of fascinating phenomena,such as quantum thermalization,many-body localization,and quantum many-body scars.This review provides a comprehensive overview of the recent advances in understanding quantum many-body scars and non-ergodic dynamics in quantum systems on superconducting-circuit platforms,ranging from theoretical mechanisms and effective models to experimental observations.
基金supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1404204 and 2022YFA1403700)the National Natural Science Foundation of China (Grant Nos. 12274086, 11534001 and 11925402)+5 种基金funding from the National Science Foundation of China (Grant Nos. 12274046, 11874094, 12147102, and 12347101)Chongqing Natural Science Foundation (Grant No. CSTB2022NSCQ-JQX0018)the Fundamental Research Funds for the Central Universities (Grant No. 2021CDJZYJH-003)Xiaomi Foundation/Xiaomi Young Talents Programthe supports of the start-up funding of Westlake Universitysupport from the Natural Sciences and Engineering Research Council of Canada (NSERC) through Discovery Grants。
文摘Simulating U(1) quantum gauge theories with spatial dimensions greater than one is of great physical significance. Here we propose a simple realization of U(1) gauge theory with Rydberg and Rydberg-dressed atom arrays. Within the experimentally accessible range, we find that the various aspects of the U(1) gauge theory can be well simulated, such as the emergence of topological sectors, incommensurability, and the Rokhsar–Kivelson point that hosts deconfined charge excitations and degenerate topological sectors. Our proposal is promising to implement experimentally and exhibits pronounced quantum dynamics.
基金supported by the National Natural Science Foundation of China(Nos.22273122,T2350009)the Guangdong Provincial Natural Science Foundation(No.2024A1515011504)computational resources and services provided by the national supercomputer center in Guangzhou.
文摘We investigate dynamical quantum phase transitions(DQPTs)in Marko-vian open quantum systems using a variational quantum simulation(VQS)algorithm based on quantum state diffusion(QSD).This approach reformulates the Lindblad master equation as an ensemble of pure-state trajectories,enabling efficient simula-tion of dissipative quantum dynam-ics with effectively reduced quantum resources.Focusing on the one-di-mensional transverse-field Ising mod-el(TFIM),we simulate quench dynamics under both local and global Lindblad dissipation.The QSD-VQS algorithm accurately captures the nonanalytic cusps in the Loschmidt rate function,and reveals their modulation by dissipation strength and system size.Notably,DQPTs are gradually suppressed under strong local dissipation,while they persist under strong global dissipation due to collective environmental effects.Benchmarking against exact Lindblad solutions confirms the high accuracy and scalability of our method.
基金Project supported by the National Key R&D Program of China(Grant Nos.2018YFA0306504 and 2018YFA0306503)the Key-Area Research and Development Program of Guang Dong Province,China(Grant No.2019B030330001)+1 种基金the National Natural Science Foundation of China(Grant Nos.91636213,11654001,91736311,91836302,and U1930201)support from Beijing Academy of Quantum Information Sciences(BAQIS)Research Program(Grant No.Y18G24)。
文摘Quantum information processing based on Rydberg atoms emerged as a promising direction two decades ago.Recent experimental and theoretical progresses have shined exciting light on this avenue.In this concise review,we will briefly introduce the basics of Rydberg atoms and their recent applications in associated areas of neutral atom quantum computation and simulation.We shall also include related discussions on quantum optics with Rydberg atomic ensembles,which are increasingly used to explore quantum computation and quantum simulation with photons.
基金Project supported by the Key-Area Research and Development Program of Guang Dong Province,China(Grant No.2019B030330001)Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)+2 种基金the National Natural Science Foundation of China(Grant Nos.12074180,12005065,12022512,and 12035007)the Key Project of Science and Technology of Guangzhou(Grant Nos.201804020055 and 2019050001)the National Key Research and Development Program of China(Grant No.2016YFA0301800)。
文摘Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.
基金supported by the National Natural Science Foundation of China(No.12304559)the Zhejiang Provincial Natural Science Foundation of China(No.LDQ23A040001).
文摘Quantum simulation,as a practical application of noisy quantum computing,has aided the study of exotic quantum matters and the implementation of algorithms that outperform classical approaches.Superconducting qubits,one of the most promising candidates for realizing universal quantum computing,possess state-of-the-art features like easy integration of qubits,long coherence time,and high-fidelity single-and two-qubit gates.These characteristics have enabled applications of digital quantum simulation in the fields of physics,chemistry,and computer science.In this review,we first present the basic concepts of superconducting qubits,quantum gates,and digital quantum simulations.We also explore recent progress in digital quantum simulations using superconducting qubits,especially in relation to quantum chemistry,quantum matters,combinatorial optimization,and quantum machine learning.Finally,we address the current challenges of digital quantum simulation with superconducting qubits,and provide a perspective on the future of the field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91321208 and 11674380)the National Key Basic Research Program of the Ministry of Science and Technology of China(Grant Nos.2014CB921202,2015CB921104,and 2016YFA0300601)
文摘Superconducting quantum bits （qubits） and circuits are the leading candidate for the implementation of solid-state quantum computation. They have also been widely used in a variety of studies of quantum physics, atomic physics, quantum optics, and quantum simulation. In this article, we will present an overview of the basic principles of the superconducting qubits, including the phase, flux, charge, and transmon （Xmon） qubits, and the progress achieved so far concerning the improvements of the device design and quantum coherence property. Experimental studies in various research fields using the superconducting qubits and circuits will be briefly reviewed.
文摘Quantum simulation has been developed extensively over the past decades,widely applied to different models to explore dynamics in the quantum regime.Rydberg atoms have strong dipole-dipole interactions and interact with each other over a long distance,which makes it straightforward to build many-body interacting quantum systems to simulate specific models.Additionally,neutral atoms are easily manipulated due to their weak interactions.These advantages make Rydberg many-body system an ideal platform to implement quantum simulations.This paper reviews several quantum simulations for different models based on Rydberg many-body systems,including quantum Ising models in one dimension and two dimensions mainly for quantum magnetism,XY model for excitation transport,SSH model for symmetry-protected topological phases,and critical self-organized behaviors in many-body systems.Besides,some challenges and promising directions of quantum simulations based on Rydberg many-body system are discussed in this paper.
基金Supported by the National Natural Science Foundation of China under Grant No 61572529
文摘Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of the absorp- tion and scattering on the transmittance of underwater quantum channel and the maximum secure transmission distance are studied. Considering the roughness of the sea surface, we simulate the performance bounds of CV QKD with different wind speeds using the Monte Carlo method. The results show that even if the secret key rate gradually reduces as the wind speed increases, the maximum transmission distance will not be affected obviously. Compared to the works regarding short-distance underwater optical communication, our research represents a significant step towards establishing secure communication between air platform and submarine vehicle.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 11934018, T2121001, 11904393, and 92065114)the CAS Strategic Priority Research Program (Grant No. XDB28000000)+1 种基金Beijing Natural Science Foundation (Grant No. Z200009)Scientific Instrument Developing Project of Chinese Academy of Sciences (Grant No. YJKYYQ20200041)。
文摘In the past years, great progresses have been made on quantum computation and quantum simulation. Increasing the number of qubits in the quantum processors is expected to be one of the main motivations in the next years, while noises in manipulation of quantum states may still be inevitable even the precision will improve. For research in this direction, it is necessary to review the available results about noisy multiqubit quantum computation and quantum simulation. The review focuses on multiqubit state generations, quantum computational advantage, and simulating physics of quantum many-body systems. Perspectives of near term noisy intermediate-quantum processors will be discussed.
基金Project supported by the State Key Development Program for Basic Research of China(Grant No.2017YFA0304300)the National Natural Science Foundation of China(Grant Nos.11934018,11747601,and 11975294)+4 种基金Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)Scientific Instrument Developing Project of Chinese Academy of Sciences(Grant No.YJKYYQ20200041)Beijing Natural Science Foundation(Grant No.Z200009)the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2020B0303030001)Chinese Academy of Sciences(Grant No.QYZDB-SSW-SYS032)。
文摘Quantum computers promise to solve finite-temperature properties of quantum many-body systems,which is generally challenging for classical computers due to high computational complexities.Here,we report experimental preparations of Gibbs states and excited states of Heisenberg X X and X X Z models by using a 5-qubit programmable superconducting processor.In the experiments,we apply a hybrid quantum–classical algorithm to generate finite temperature states with classical probability models and variational quantum circuits.We reveal that the Hamiltonians can be fully diagonalized with optimized quantum circuits,which enable us to prepare excited states at arbitrary energy density.We demonstrate that the approach has a self-verifying feature and can estimate fundamental thermal observables with a small statistical error.Based on numerical results,we further show that the time complexity of our approach scales polynomially in the number of qubits,revealing its potential in solving large-scale problems.
文摘Vibrational degrees of freedom in trapped-ion systems have recently been gaining attention as a quantum resource,beyond the role as a mediator for entangling quantum operations on internal degrees of freedom,because of the large available Hilbert space.The vibrational modes can be represented as quantum harmonic oscillators and thus offer a Hilbert space with infinite dimensions.Here we review recent theoretical and experimental progress in the coherent manipulation of the vibrational modes,including bosonic encoding schemes in quantum information,reliable and efficient measurement techniques,and quantum operations that allow various quantum simulations and quantum computation algorithms.We describe experiments using the vibrational modes,including the preparation of non-classical states,molecular vibronic sampling,and applications in quantum thermodynamics.We finally discuss the potential prospects and challenges of trapped-ion vibrational-mode quantum information processing.
基金funded by the National Natural Science Foundation of China (Grant No. 12175002)Beijing Natural Science Foundation (Grant No. 1222020)NCUT Talents Project and Special Fund。
文摘Different from the Hermitian case, non-Hermitian(NH) systems have novel properties and strongly relate to open and dissipative quantum systems. In this work, we investigate how to simulate τ-anti-pseudo-Hermitian systems in a Hermitian quantum device using linear combinations of unitaries and duality quantum algorithm. Specifying the τ to time-reversal(T) and parity-time-reversal(PT) operators, we construct the two NH two-level systems, design quantum circuits including three qubits, and decide the quantum gates explicitly in detail. We also calculate the success probabilities of the simulation.Experimental implementation can be expected in small quantum simulator.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0303301)the National Natural Science Foundation of China(Grant Nos.11674009 and 11921005)+1 种基金the Beijing Natural Science Foundation,China(Grant No.JQ18002)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)。
文摘This review summarizes the requirement of low temperature conditions in existing experimental approaches to quantum computation and quantum simulation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11653001,11653004,and 60836001).
文摘Superconducting circuits based on Josephson junctions are regarded as one of the most promising technologies for the implementation of scalable quantum computers.This review presents the basic principles of superconducting qubits and shows the progress of quantum computing and quantum simulation based on superconducting qubits in recent years.The experimental realization of gate operations,readout,error correction codes,as well as some quantum algorithms are summarized,followed by an introduction of quantum simulation.And then some important applications in fields including condensed matter physics,quantum annealing,and quantum chemistry are discussed.
基金supported by China Postdoctoral Science Foundation(Grant No.2020T130643)the Fundamental Research Funds for the Central Universities,and the National Natural Science Foundation of China(Grant No.12047554)+5 种基金support from the National Key Research and Development Program of China(Grant No.2016YFA0300502)the Research Grants Council of Hong Kong SAR China(Grant No.17303019)support from the National Key R&D Program of China(Grant Nos.2016YFA0302104 and 2016YFA0300600)the National Natural Science Foundation of China(Grant Nos.11774406 and 11934018)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)Beijing Academy of Quantum Information Science(Grant No.Y18G07)。
文摘Recently,quantum simulation of low-dimensional lattice gauge theories(LGTs)has attracted many interests,which may improve our understanding of strongly correlated quantum many-body systems.Here,we propose an implementation to approximate Z;LGT on superconducting quantum circuits,where the effective theory is a mixture of a LGT and a gauge-broken term.By using matrix product state based methods,both the ground state properties and quench dynamics are systematically investigated.With an increase of the transverse(electric)field,the system displays a quantum phase transition from a disordered phase to a translational symmetry breaking phase.In the ordered phase,an approximate Gauss law of the Z;LGT emerges in the ground state.Moreover,to shed light on the experiments,we also study the quench dynamics,where there is a dynamical signature of the spontaneous translational symmetry breaking.The spreading of the single particle of matter degree is diffusive under the weak transverse field,while it is ballistic with small velocity for the strong field.Furthermore,due to the emergent Gauss law under the strong transverse field,the matter degree can also exhibit confinement dynamics which leads to a strong suppression of the nearest-neighbor hopping.Our results pave the way for simulating the LGT on superconducting circuits,including the quantum phase transition and quench dynamics.
基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0303205)the National Natural Science Foundation of China(Grant Nos.12104282 and 12305014)+1 种基金the Initiative in Quantum Information Technologies of Anhui Province(Grant No.AHY050000)the Fundamental Research Funds for the Central Universities(Grant Nos.JZ2024HGTB0253 and JZ2023HGTA0172).
文摘Counterdiabatic driving (CD) offers a fast and robust route to manipulate quantum systems, which has widespreadapplications in quantum technologies. However, for higher-dimensional complex systems, the exact CD term involving thespectral properties of the system is difficult to calculate and generally takes a complicated form, impeding its experimentalrealization. Recently, many approximate methods have been proposed for designing CD passages in many-body systems. Inthis topical review, we focus on the CD formalism and briefly introduce several experimental constructions and applicationsof approximate CD driving in spin-chain models with nuclear magnetic resonance (NMR) systems.
基金supported by the National Natural Science Foundation of China(Grant No.12005065)the Guangdong Basic and Applied Basic Research Fund(Grant No.2021A1515010317)。
文摘The quantum critical regime marks a zone in the phase diagram where quantum fluctuation around the critical point plays a significant role at finite temperatures.While it is of great physical interest,simulation of the quantum critical regime can be difficult on a classical computer due to its intrinsic complexity.Herein,we propose a variational approach,which minimizes the variational free energy,to simulate and locate the quantum critical regime on a quantum computer.The variational quantum algorithm adopts an ansatz by performing an unitary operator on a product of a single-qubit mixed state,in which the entropy can be analytically obtained from the initial state,and thus the free energy can be accessed conveniently.With numeral simulation,using the one-dimensional Kitaev model as a demonstration we show that the quantum critical regime can be identified by accurately evaluating the temperature crossover line.Moreover,the dependencies of both the correlation length and the phase coherence time with temperature are evaluated for the thermal states.Our work suggests a practical way as well as a first step for investigating quantum critical systems at finite temperatures on quantum devices with few qubits.
基金Supported by the Basic Science Research Program through the National Research Foundation of Korea Funded by the Ministry of Education,Science and Technology under Grant No 2012-0002777
文摘We evaluate the impact of temperature on the output behavior of a carbon nanotube field effect transistor （CNFET） based chaotic generator. The sources cause the variations in both current-voltage characteristics of the CNFET device and an overall chaotic circuit is pointed out. To verify the effect of temperature variation on the output dynamics of the chaotic circuit, a simulation is performed by employing the CNFET compact model of Wong et al. in HSPICE with a temperature range from -100℃ to 100℃. The obtained results with time series, frequency spectra, and bifurcation diagram from the simulation demonstrate that temperature plays a significant role in the output dynamics of the CNFET-based chaotic circuit. Thus, temperature-related issues should be taken into account while designing a high-quality chaotic generator with high stability.
