Although the multi-level structure of superconducting qubits may result in calculation errors, it can be rationally used to effectively improve the speed of gate operations. Utilizing a current-biased Josephson juncti...Although the multi-level structure of superconducting qubits may result in calculation errors, it can be rationally used to effectively improve the speed of gate operations. Utilizing a current-biased Josephson junction （A-type rf-SQUID） as a tunable coupler for superconducting transmission line resonators （TLRs）, under the large detuning condition, we demonstrate the controllable generation of entangled coherent states in circuit quantum electrodynamics （circuit QED）. The coupling between the TLRs and the qubit can be effectively regulated by an external bias current or coupling capacitor. Further investigations indicate that the maximum entangled state can be obtained through measuring the excited state of the superconducting qubits. Then, the influence of the TLR [tecay on the prepared entangled states is analyzed.展开更多
We study the entanglement dynamics between two strongly-AC-driven superconducting charge qubitscoupled collectively to a zero temperature,dissipative resonator and find an unusual feather that the competing ofcreation...We study the entanglement dynamics between two strongly-AC-driven superconducting charge qubitscoupled collectively to a zero temperature,dissipative resonator and find an unusual feather that the competing ofcreation and annihilation of entanglement can lead to entanglement increasing,sudden death and revival.We alsocalculate the dependence of the death time on the initial state of the system.展开更多
Construction of optimal gate operations is significant for quantum computation.Here an efficient scheme is proposed for performing shortcut-based quantum gates on superconducting qubits in circuit quantum electrodynam...Construction of optimal gate operations is significant for quantum computation.Here an efficient scheme is proposed for performing shortcut-based quantum gates on superconducting qubits in circuit quantum electrodynamics(QED).Two four-level artificial atoms of Cooper-pair box circuits,having sufficient level anharmonicity,are placed in a common quantized field of circuit QED and are driven by individual classical microwaves.Without the effect of cross resonance,one-qubit NOT gate and phase gate in a decoupled atom can be implemented using the invariant-based shortcuts to adiabaticity.With the assistance of cavity bus,a one-step SWAP gate can be obtained within a composite qubit-photon-qubit system by inversely engineering the classical drivings.We further consider the gate realizations by adjusting the microwave fields.With the accessible decoherence rates,the shortcut-based gates have high fidelities.The present strategy could offer a promising route towards fast and robust quantum computation with superconducting circuits experimentally.展开更多
t We propose theoretical schemes to generate highly entangled cluster state with superconducting qubits in a circuit QED architecture. Charge qubits are located inside a superconducting transmission line, which serves...t We propose theoretical schemes to generate highly entangled cluster state with superconducting qubits in a circuit QED architecture. Charge qubits are located inside a superconducting transmission line, which serves as a quantum data bus. We show that large clusters state can be efficiently generated in just one step with the longrange Ising-like unitary operators. The quantum operations which are generally realized by two coupling mechanisms： either voltage coupling or current coupling, depend only on global geometric features and are insensitive not only to the thermal state of the transmission line but also to certain random operation errors. Thus high-fidelity one-way quantum computation can be achieved.展开更多
We propose a theoretical scheme for realizing the general conditional phase shift gate of charge qubits situated in a high-Q superconducting transmission line resonator. The phase shifting angle can be tuned from 0 to...We propose a theoretical scheme for realizing the general conditional phase shift gate of charge qubits situated in a high-Q superconducting transmission line resonator. The phase shifting angle can be tuned from 0 to 27r by simply adjusting the qubit-resonator detuning and the interaction time. Based on this gate proposal, we give a detailed procedure to implement the three-qubit quantum Fourier transform with circuit quantum eleetrodynamics （QED）. A careful analysis of the decoherence sources shows that the algorithm can be achieved with a high fidelity using current circuit QED techniques.展开更多
A fast scheme to generate Greenberger-Horne-Zeilinger states between different cavities in circuit QED systems is proposed.To implement this scheme,we design a feasible experimental device with three qubits and three ...A fast scheme to generate Greenberger-Horne-Zeilinger states between different cavities in circuit QED systems is proposed.To implement this scheme,we design a feasible experimental device with three qubits and three cavities.In this device,all the couplings between qubit and qubit,cavity and qubit are tunable and are independent with frequencies,and thus the shortcut to adiabaticity technique can be directly applied in our scheme.It is demonstrated that the GHZ state can be generated rapidly with high fidelity in our scheme.展开更多
We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The tw...We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The two logic states of a SPS qubit here are represented by the vacuum state and the single-photon state of a cavity,while the two logic states of a CS qubit are encoded with two coherent states of a cavity.Because of using only one superconducting qutrit as the coupler,the circuit architecture is significantly simplified.The operation time for the state transfer does not increase with the increasing of the number of qubits.When the dissipation of the system is negligible,the quantum state can be transferred in a deterministic way since no measurement is required.Furthermore,the higher-energy intermediate level of the coupler qutrit is not excited during the entire operation and thus decoherence from the qutrit is greatly suppressed.As a specific example,we numerically demonstrate that the high-fidelity transfer of a Bell state of two SPS qubits onto two CS qubits is achievable within the present-day circuit QED technology.Finally,it is worthy to note that when the dissipation is negligible,entangled states of n CS qubits can be transferred back onto n SPS qubits by performing reverse operations.This proposal is quite general and can be extended to accomplish the same task,by employing a natural or artificial atom to couple 2nmicrowave or optical cavities.展开更多
In recent years,cat-state encoding and high-dimensional entanglement have attracted much attention.However,previous works are limited to generation of entangled states of cat-state qubits(two-dimensional entanglement ...In recent years,cat-state encoding and high-dimensional entanglement have attracted much attention.However,previous works are limited to generation of entangled states of cat-state qubits(two-dimensional entanglement with cat-state encoding),while how to prepare entangled states of cat-state qutrits or qudits(high-dimensional entanglement with cat-state encoding)has not been investigated.We here propose to generate a maximally-entangled state of multiple cat-state qutrits(three-dimensional entanglement by cat-state encoding)in circuit QED.The entangled state is prepared with multiple microwave cavities coupled to a superconducting flux ququart(a four-level quantum system).This proposal operates essentially by the cavity-qutrit dispersive interaction.The circuit hardware resource is minimized because only a coupler ququart is employed.The higher intermediate level of the ququart is occupied only for a short time,thereby decoherence from this level is greatly suppressed during the state preparation.Remarkably,the state preparation time does not depend on the number of the qutrits,thus it does not increase with the number of the qutrits.As an example,our numerical simulations demonstrate that,with the present circuit QED technology,the high-fidelity preparation is feasible for a maximally-entangled state of two cat-state qutrits.Furthermore,we numerically analyze the effect of the inter-cavity crosstalk on the scalability of this proposal.This proposal is universal and can be extended to accomplish the same task with multiple microwave or optical cavities coupled to a natural or artificial four-level atom.展开更多
We suggest a scheme to probe critical phenomena at a quantum phase transition (QPT) using the quantum correlation of two photonic modes simultaneously coupled to a critical system. As an experimentally accessible phys...We suggest a scheme to probe critical phenomena at a quantum phase transition (QPT) using the quantum correlation of two photonic modes simultaneously coupled to a critical system. As an experimentally accessible physical implementation,a circuit QED system is formed by a capacitively coupled Josephson junction qubit array interacting with one superconducting transmission line resonator (TLR). It realizes an Ising chain in the transverse field (ICTF) which interacts with the two magnetic modes propagating in the TLR. We demonstrate that in the vicinity of criticality the originally independent fields tend to display photon bunching effects due to their interaction with the ICTF. Thus,the occurrence of the QPT is reflected by the quantum characteristics of the photonic fields.展开更多
Hybrid systems consisting of superconducting circuits and magnon systems are a promising platform for quantum technology.However,realizing high-fidelity magnon state preparation and manipulation remains an outstanding...Hybrid systems consisting of superconducting circuits and magnon systems are a promising platform for quantum technology.However,realizing high-fidelity magnon state preparation and manipulation remains an outstanding challenge due to the complexity of interactions and noise sources in hybrid systems.Here,we propose a coherence-preserving magnon state manipulation scheme.By engineering a superconducting-magnon coupling pulse and combining it with dynamical decoupling pulses,we design a composite pulse sequence.We demonstrate the manipulation and preparation of non-classical states of magnons with a fidelity of up to 98%under realistic conditions.These designs significantly improve the fidelity of manipulation and robustness to noise in hybrid systems compared to existing schemes.These results pave the way for practical applications of quantum magnonics platforms.展开更多
We propose schemes to realize robust quantum states transfer between distant resonators using the topological edge states of a one-dimensional circuit quantum electrodynamics(QED)lattice.Analyses show that the distrib...We propose schemes to realize robust quantum states transfer between distant resonators using the topological edge states of a one-dimensional circuit quantum electrodynamics(QED)lattice.Analyses show that the distribution of edge states can be regulated accordingly with the on-site defects added on the resonators.And we can achieve different types of quantum state transfer without adjusting the number of lattices.Numerical simulations demonstrate that the on-site defects can be used as a change-over switch for high-fidelity single-qubit and two-qubit quantum states transfer.This work provides a viable prospect for flexible quantum state transfer in solid-state topological quantum system.展开更多
In this theoretical work,we describe a mechanism for the coupling between a plane structure consisting of four quantum dots and a resonator.We systematically study the dependence of the quadruple coupling strength and...In this theoretical work,we describe a mechanism for the coupling between a plane structure consisting of four quantum dots and a resonator.We systematically study the dependence of the quadruple coupling strength and the qubit decoherence rate and point out the optimized operating position of the hybrid system.According to the transmission given by the input-output theory,the signatures in the resonator spectrum are predicted.Furthermore,based on the parameters already achieved in previous works,we prove that the device described in this paper can achieve the strong coupling limit,i.e.,this approach can be used for system extension under the existing technical conditions.Our results show an effective and promotable approach to couple quantum dot structures in plane with the resonator and propose a meaningful extension method.展开更多
Superconducting circuit quantum electrodynamics(QED)architecture composed of superconducting qubit and resonator is a powerful platform for exploring quantum physics and quantum information processing.By employing tec...Superconducting circuit quantum electrodynamics(QED)architecture composed of superconducting qubit and resonator is a powerful platform for exploring quantum physics and quantum information processing.By employing techniques developed for superconducting quantum computing,we experimentally investigate phase-sensitive Landau-Zener-Stückelberg(LZS)interference phenomena in a circuit QED.Our experiments cover an extensive range of LZS transition parameters and demonstrate the LZS induced Rabi-like oscillation as well as phase-dependent steady-state population.展开更多
Here, we propose a simple scheme to realize a one-dimensional （1D） modulated Rice-Mele model （RMM） and investigate its topological properties with a 1D circuit quantum electrodynamics （QED） lattice. The system c...Here, we propose a simple scheme to realize a one-dimensional （1D） modulated Rice-Mele model （RMM） and investigate its topological properties with a 1D circuit quantum electrodynamics （QED） lattice. The system can be mapped into a Chern insulator model by introducing a period parameter. Interestingly and surprisingly, we found that the circuit-QED lattice system always exhibits topologically nonttrvial phases if both the nearest-neighbor hopping strength between two resonators and the qubitassisted on-site potentials are alternately changed in the direction of the lattice. The numerical results show that the topological phases can be obtained by introducing an additional modulation parameter and both the edge state and topological invariant can be unambiguously seen with the existence of decay and disorders, even with few resonators in the lattice.展开更多
We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artifi...We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.展开更多
We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum ...We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.展开更多
High-dimensional quantum systems, such as qutrits(quantum three-level systems), have multiple accessible energy levels beyond the two-level qubits. Therefore, qutrits can offer a larger state space to improve the effi...High-dimensional quantum systems, such as qutrits(quantum three-level systems), have multiple accessible energy levels beyond the two-level qubits. Therefore, qutrits can offer a larger state space to improve the efficiency of quantum computation. Here, we demonstrate a high-fidelity iSWAP-like gate operation on a frequency-tunable superconducting qutrits system. The superconducting quantum system consists of two qutrits that are coupled via a resonator with fixed qutrit-resonator coupling strengths. Through designing the frequency pulse profile and optimizing the parameter values,the gate error can be suppressed below 1.5 × 10^(-3). To bear out the feasibility of the proposal, we have conducted our study with experimentally accessible parameters. As the resonator can mediate the interaction between the irrelevant qutrits, the presented approach can also be used to couple multiple qutrits together, providing a good platform for quantum information processing.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11264015)
文摘Although the multi-level structure of superconducting qubits may result in calculation errors, it can be rationally used to effectively improve the speed of gate operations. Utilizing a current-biased Josephson junction （A-type rf-SQUID） as a tunable coupler for superconducting transmission line resonators （TLRs）, under the large detuning condition, we demonstrate the controllable generation of entangled coherent states in circuit quantum electrodynamics （circuit QED）. The coupling between the TLRs and the qubit can be effectively regulated by an external bias current or coupling capacitor. Further investigations indicate that the maximum entangled state can be obtained through measuring the excited state of the superconducting qubits. Then, the influence of the TLR [tecay on the prepared entangled states is analyzed.
基金Supported by Hunan Provincial Natural Science Foundation of China under Grant No. 10J J6010the Key Project Foundation and the Youngth Foundation of Education Commission of Hunan Province of China under Grant Nos. 10A095, 09B079the Youth Foundation from Huaihua University of China under Grant No. HHUQ2009-09
文摘We study the entanglement dynamics between two strongly-AC-driven superconducting charge qubitscoupled collectively to a zero temperature,dissipative resonator and find an unusual feather that the competing ofcreation and annihilation of entanglement can lead to entanglement increasing,sudden death and revival.We alsocalculate the dependence of the death time on the initial state of the system.
基金Project supported by the Natural Science Foundation of Henan Province,China (Grant No. 212300410388)the “316” Project Plan of Xuchang University
文摘Construction of optimal gate operations is significant for quantum computation.Here an efficient scheme is proposed for performing shortcut-based quantum gates on superconducting qubits in circuit quantum electrodynamics(QED).Two four-level artificial atoms of Cooper-pair box circuits,having sufficient level anharmonicity,are placed in a common quantized field of circuit QED and are driven by individual classical microwaves.Without the effect of cross resonance,one-qubit NOT gate and phase gate in a decoupled atom can be implemented using the invariant-based shortcuts to adiabaticity.With the assistance of cavity bus,a one-step SWAP gate can be obtained within a composite qubit-photon-qubit system by inversely engineering the classical drivings.We further consider the gate realizations by adjusting the microwave fields.With the accessible decoherence rates,the shortcut-based gates have high fidelities.The present strategy could offer a promising route towards fast and robust quantum computation with superconducting circuits experimentally.
文摘t We propose theoretical schemes to generate highly entangled cluster state with superconducting qubits in a circuit QED architecture. Charge qubits are located inside a superconducting transmission line, which serves as a quantum data bus. We show that large clusters state can be efficiently generated in just one step with the longrange Ising-like unitary operators. The quantum operations which are generally realized by two coupling mechanisms： either voltage coupling or current coupling, depend only on global geometric features and are insensitive not only to the thermal state of the transmission line but also to certain random operation errors. Thus high-fidelity one-way quantum computation can be achieved.
基金Supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China under Grant No. 200524the Program for New Century Excellent Talents of China under Grant No. 06-0920
文摘We propose a theoretical scheme for realizing the general conditional phase shift gate of charge qubits situated in a high-Q superconducting transmission line resonator. The phase shifting angle can be tuned from 0 to 27r by simply adjusting the qubit-resonator detuning and the interaction time. Based on this gate proposal, we give a detailed procedure to implement the three-qubit quantum Fourier transform with circuit quantum eleetrodynamics （QED）. A careful analysis of the decoherence sources shows that the algorithm can be achieved with a high fidelity using current circuit QED techniques.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant Nos.11974290 and 11875327the Natural Science Foundation of Guangdong Province under Grant No.2016A030313313+1 种基金the Fundamental Research Funds for the Central Universitiesthe Sun Yat-Sen University Science Foundation.
文摘A fast scheme to generate Greenberger-Horne-Zeilinger states between different cavities in circuit QED systems is proposed.To implement this scheme,we design a feasible experimental device with three qubits and three cavities.In this device,all the couplings between qubit and qubit,cavity and qubit are tunable and are independent with frequencies,and thus the shortcut to adiabaticity technique can be directly applied in our scheme.It is demonstrated that the GHZ state can be generated rapidly with high fidelity in our scheme.
基金This work was partly supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.11074062,11374083,and 11774076)the Key-Area Research and Development Program of GuangDong province(Grant No.2018B030326001)the NKRDP of China(Grant No.2016YFA0301802).
文摘We present a way to transfer maximally-or partially-entangled states of n single-photon-state(SPS)qubits onto ncoherent-state(CS)qubits,by employing 2nmicrowave cavities coupled to a superconducting flux qutrit.The two logic states of a SPS qubit here are represented by the vacuum state and the single-photon state of a cavity,while the two logic states of a CS qubit are encoded with two coherent states of a cavity.Because of using only one superconducting qutrit as the coupler,the circuit architecture is significantly simplified.The operation time for the state transfer does not increase with the increasing of the number of qubits.When the dissipation of the system is negligible,the quantum state can be transferred in a deterministic way since no measurement is required.Furthermore,the higher-energy intermediate level of the coupler qutrit is not excited during the entire operation and thus decoherence from the qutrit is greatly suppressed.As a specific example,we numerically demonstrate that the high-fidelity transfer of a Bell state of two SPS qubits onto two CS qubits is achievable within the present-day circuit QED technology.Finally,it is worthy to note that when the dissipation is negligible,entangled states of n CS qubits can be transferred back onto n SPS qubits by performing reverse operations.This proposal is quite general and can be extended to accomplish the same task,by employing a natural or artificial atom to couple 2nmicrowave or optical cavities.
文摘In recent years,cat-state encoding and high-dimensional entanglement have attracted much attention.However,previous works are limited to generation of entangled states of cat-state qubits(two-dimensional entanglement with cat-state encoding),while how to prepare entangled states of cat-state qutrits or qudits(high-dimensional entanglement with cat-state encoding)has not been investigated.We here propose to generate a maximally-entangled state of multiple cat-state qutrits(three-dimensional entanglement by cat-state encoding)in circuit QED.The entangled state is prepared with multiple microwave cavities coupled to a superconducting flux ququart(a four-level quantum system).This proposal operates essentially by the cavity-qutrit dispersive interaction.The circuit hardware resource is minimized because only a coupler ququart is employed.The higher intermediate level of the ququart is occupied only for a short time,thereby decoherence from this level is greatly suppressed during the state preparation.Remarkably,the state preparation time does not depend on the number of the qutrits,thus it does not increase with the number of the qutrits.As an example,our numerical simulations demonstrate that,with the present circuit QED technology,the high-fidelity preparation is feasible for a maximally-entangled state of two cat-state qutrits.Furthermore,we numerically analyze the effect of the inter-cavity crosstalk on the scalability of this proposal.This proposal is universal and can be extended to accomplish the same task with multiple microwave or optical cavities coupled to a natural or artificial four-level atom.
基金Supported by the National Basic Research Program of China (Grant No. 2006CB921106)the National Natural Science Foundation of China (Grant No. 10874098)the ECIST-FET Project EuroSQUIP, the Swiss SNF, and the NCCR Nanoscience
文摘We suggest a scheme to probe critical phenomena at a quantum phase transition (QPT) using the quantum correlation of two photonic modes simultaneously coupled to a critical system. As an experimentally accessible physical implementation,a circuit QED system is formed by a capacitively coupled Josephson junction qubit array interacting with one superconducting transmission line resonator (TLR). It realizes an Ising chain in the transverse field (ICTF) which interacts with the two magnetic modes propagating in the TLR. We demonstrate that in the vicinity of criticality the originally independent fields tend to display photon bunching effects due to their interaction with the ICTF. Thus,the occurrence of the QPT is reflected by the quantum characteristics of the photonic fields.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12304401 and 11974336)the National Key Research and Development Program of China(Grant No.2017YFA0304100)。
文摘Hybrid systems consisting of superconducting circuits and magnon systems are a promising platform for quantum technology.However,realizing high-fidelity magnon state preparation and manipulation remains an outstanding challenge due to the complexity of interactions and noise sources in hybrid systems.Here,we propose a coherence-preserving magnon state manipulation scheme.By engineering a superconducting-magnon coupling pulse and combining it with dynamical decoupling pulses,we design a composite pulse sequence.We demonstrate the manipulation and preparation of non-classical states of magnons with a fidelity of up to 98%under realistic conditions.These designs significantly improve the fidelity of manipulation and robustness to noise in hybrid systems compared to existing schemes.These results pave the way for practical applications of quantum magnonics platforms.
基金supported by the National Natural Science Foundation of China(Grant Nos.61801280,61805134,and 61822114)the Applied Fundamental Research Projects of Shanxi Province,China(Grant No.201801D221015)Science and Technology Innovation Project of Shanxi Normal University(Grant No.2020XSY032)。
文摘We propose schemes to realize robust quantum states transfer between distant resonators using the topological edge states of a one-dimensional circuit quantum electrodynamics(QED)lattice.Analyses show that the distribution of edge states can be regulated accordingly with the on-site defects added on the resonators.And we can achieve different types of quantum state transfer without adjusting the number of lattices.Numerical simulations demonstrate that the on-site defects can be used as a change-over switch for high-fidelity single-qubit and two-qubit quantum states transfer.This work provides a viable prospect for flexible quantum state transfer in solid-state topological quantum system.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92265113,12074368,and 12034018).
文摘In this theoretical work,we describe a mechanism for the coupling between a plane structure consisting of four quantum dots and a resonator.We systematically study the dependence of the quadruple coupling strength and the qubit decoherence rate and point out the optimized operating position of the hybrid system.According to the transmission given by the input-output theory,the signatures in the resonator spectrum are predicted.Furthermore,based on the parameters already achieved in previous works,we prove that the device described in this paper can achieve the strong coupling limit,i.e.,this approach can be used for system extension under the existing technical conditions.Our results show an effective and promotable approach to couple quantum dot structures in plane with the resonator and propose a meaningful extension method.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2018B030326001)the National Natural Science Foundation of China(Grant Nos.U1801661,11874065,and Youth Project No.11904158)+2 种基金the Guangdong Provincial Key Laboratory(Grant No.2019B121203002)the Natural Science Foundation of Hunan Province,China(Grant No.2018JJ1031)the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant Nos.JCYJ20170412152620376 and YTDPT20181011104202253)。
文摘Superconducting circuit quantum electrodynamics(QED)architecture composed of superconducting qubit and resonator is a powerful platform for exploring quantum physics and quantum information processing.By employing techniques developed for superconducting quantum computing,we experimentally investigate phase-sensitive Landau-Zener-Stückelberg(LZS)interference phenomena in a circuit QED.Our experiments cover an extensive range of LZS transition parameters and demonstrate the LZS induced Rabi-like oscillation as well as phase-dependent steady-state population.
基金supported by the National Natural Science Foundation of China(Grant Nos.11465020,11264042,61465013,and 11564041)the Project of Jilin Science and Technology Development for Leading Talent of Science and Technology Innovation in Middle and Young and Team Project(Grant No.20160519022JH)
文摘Here, we propose a simple scheme to realize a one-dimensional （1D） modulated Rice-Mele model （RMM） and investigate its topological properties with a 1D circuit quantum electrodynamics （QED） lattice. The system can be mapped into a Chern insulator model by introducing a period parameter. Interestingly and surprisingly, we found that the circuit-QED lattice system always exhibits topologically nonttrvial phases if both the nearest-neighbor hopping strength between two resonators and the qubitassisted on-site potentials are alternately changed in the direction of the lattice. The numerical results show that the topological phases can be obtained by introducing an additional modulation parameter and both the edge state and topological invariant can be unambiguously seen with the existence of decay and disorders, even with few resonators in the lattice.
基金Project supported by the Science Funds from the Ministry of Science and Technology of China(Grant Nos.2014CB921401,2017YFA0304300,2014CB921202,and 2016YFA0300601)the National Natural Science Foundation of China(Grant No.11674376)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB07010300)
文摘We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.
基金Project supported by the National Natural Science Foundation of China(Grant No.12174300)the Natural Science Foundation of Hubei Province of China(Grant No.2020CFB748)+2 种基金the Natural Science Foundation of Shandong Province of China(Grant Nos.ZR2021MA042 and ZR2021MA078)the Program for Science and Technology Innovation Team in Colleges of Hubei Province of China(Grant No.T2021012)the Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(Grant Nos.BK202113,BK201906,and BK202008)。
文摘We propose an efficient method for the generation of perfect W states on three microwave superconducting resonators,of which the two nearest neighbors are coupled by a symmetric direct current superconducting quantum interference device(dc-SQUID).With suitable external magnetic fluxes applied to the dc-SQUID symmetry loops,on-chip tunable interactions between neighboring resonators can be realized,and different perfect W states can be deterministically created on-demand in one step.Numerical simulations show that high-fidelity target states can be generated and our scheme is robust against imperfect parameter tuning and environment-induced decoherence.The present work may have potential applications for implementing quantum computation and quantum information processing based on microwave photons.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12105146 and 12175104)supported by the National Natural Science Foundation of China (Grant No. 61871234)sponsored by NUPTSF (Grant No. NY220178)。
文摘High-dimensional quantum systems, such as qutrits(quantum three-level systems), have multiple accessible energy levels beyond the two-level qubits. Therefore, qutrits can offer a larger state space to improve the efficiency of quantum computation. Here, we demonstrate a high-fidelity iSWAP-like gate operation on a frequency-tunable superconducting qutrits system. The superconducting quantum system consists of two qutrits that are coupled via a resonator with fixed qutrit-resonator coupling strengths. Through designing the frequency pulse profile and optimizing the parameter values,the gate error can be suppressed below 1.5 × 10^(-3). To bear out the feasibility of the proposal, we have conducted our study with experimentally accessible parameters. As the resonator can mediate the interaction between the irrelevant qutrits, the presented approach can also be used to couple multiple qutrits together, providing a good platform for quantum information processing.
