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
We theoretically study the system of a superconducting transmission line resonator coupled to two interacting super- conducting flux qubits. It is shown that under certain conditions the resonator mode can be tuned to...We theoretically study the system of a superconducting transmission line resonator coupled to two interacting super- conducting flux qubits. It is shown that under certain conditions the resonator mode can be tuned to two-photon resonance between the ground state and the highest excited state while the middle excited states are far-off resonance. Furthermore, we study the steady-state properties of the flux qubits and resonator, such as the photon statistics, the spectrum and squeezing of the resonator, and demonstrate that two-photon laser can be implemented with current experimental technology.展开更多
We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and on...We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and one superconducting quantum interference device （SQUID） type charge qubit, which acts as an artificial atom. It is shown that in the dispersive regime of the eircuit-QED system, a controllable cross-Kerr interaction can be obtained by properly preparing the initial state of the qubit, and a large cross-phase shift between two microwave fields in the two TLRs can then be reached. Based on this cross-Kerr interaction, we show how to create a macroscopic entangled state between the two TLRs.展开更多
We propose a scheme to fast prepare the three-qubit W state via superadiabatic-based shortcuts in a circuit quantumelectrodynamics (circuit QED) system. We derive the effective Hamiltonian to suppress the unwanted tra...We propose a scheme to fast prepare the three-qubit W state via superadiabatic-based shortcuts in a circuit quantumelectrodynamics (circuit QED) system. We derive the effective Hamiltonian to suppress the unwanted transitions betweendifferent eigenstates by counterdiabatic driving, and obtain the W state with high-fidelity based on the superadiabaticpassage. The numerical simulation results demonstrate that the proposed scheme can accelerate the evolution, and is moreefficient than that with the adiabatic passage. In addition, the proposed scheme is robust to the decoherence caused by theresonator decay and qubit relaxation, and does not need additional parameters, which could be feasible in experiment.展开更多
We demonstrate the controllable generation of multi-photon Fock states in circuit quantum electrodynamics （circuit QED）. The external bias flux regulated by a counter can effectively adjust the bias time on each sup...We demonstrate the controllable generation of multi-photon Fock states in circuit quantum electrodynamics （circuit QED）. The external bias flux regulated by a counter can effectively adjust the bias time on each superconducting flux qubit so that each flux qubit can pass in turn through the circuit cavity and thereby avoid the effect of decoherence. We further investigate the quantum correlation dynamics of coupling superconducting qubits in a Fock state. The results reveal that the lower the photon number of the light field in the number state, the stronger the interaction between qubits is, then the more beneficial to maintaining entanglement between qubits it will be.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
We give the brief review on the related definition of the geometric phase independent of specific physical system based on the displacement opreator and the sqeezed operator, then show how the displacement operator an...We give the brief review on the related definition of the geometric phase independent of specific physical system based on the displacement opreator and the sqeezed operator, then show how the displacement operator and the squeezed operator can induce the general geometric phase. By means of the displacement operator and the squeezed operator concerning the circuit cavity mode state along a closed path in the phase space, we discuss specifically how to implement a two-qubit geometric phase gate in circuit quantum electrodynamics with both single photon interaction and two-photon interaction between the superconducting qubits and the circuit cavity modes. The experimental feasibility is discussed in detail.展开更多
We study the influence of multi-photon processes on the geometric quantum computation in the systems of superconducting qubits based on the displacement-like and the general squeezed operator methods. As an example, w...We study the influence of multi-photon processes on the geometric quantum computation in the systems of superconducting qubits based on the displacement-like and the general squeezed operator methods. As an example, we focus on the question about how to implement a two-qubit geometric phase gate using superconducting circuit quantum electrodynamics with both single- and two-photon interaction between the qubits and the cavity modes. We find that the multiphoton processes are not only controllable but also improve the gating speed. The comparison with other physical systems and experimental feasibility are discussed in detail.展开更多
Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation.To satisfy the connectivity requirements and reduce the lithographic com...Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation.To satisfy the connectivity requirements and reduce the lithographic complexity,utilizing the qubit array structure and the circuit quantum electrodynamics(cQED)architecture together is expected to be a feasible scaling scheme.A triple-quantum dot(TQD)coupled with a superconducting resonator is regarded as a basic cell to demonstrate this extension scheme.In this article,we investigate a system consisting of a silicon TQD and a high-impedance TiN coplanar waveguide(CPW)resonator.The TQD can couple to the resonator via the right double-quantum dot(RDQD),which reaches the strong coupling regime with a charge–photon coupling strength of g0/(2p)=175 MHz.Moreover,we illustrate the high tunability of the TQD through the characterization of stability diagrams,quadruple points(QPs),and the quantum cellular automata(QCA)process.Our results contribute to fostering the exploration of silicon-based qubit integration.展开更多
Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chi...Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chip is a highly desirable but challenging goal.Here we propose a hybrid architecture that utilizes a high-impedance SQUID array resonator as a quantum bus,thereby coherently coupling different solid-state qubits.We employ a resonant exchange spin qubit hosted in a triple quantum dot and a superconducting transmon qubit.Since this hybrid system is highly tunable,it can operate in a dispersive regime,where the interaction between the different qubits is mediated by virtual photons.By utilizing such interactions,entangling gate operations between different qubits can be realized in a short time of 30 ns with a fidelity of up to 96.5%under realistic parameter conditions.Further utilizing this interaction,remote entangled state between different qubits can be prepared and is robust to perturbations of various parameters.These results pave the way for exploring efficient fault-tolerant quantum computation on hybrid quantum architecture platforms.展开更多
We propose an efficient scheme to generate multiqubit Greenberger-ttorne--Zeilinger （GHZ） states by one- step quantum operation in a driven circuit quantum electrodyna.mics （QED） system. Our proposal is based on a...We propose an efficient scheme to generate multiqubit Greenberger-ttorne--Zeilinger （GHZ） states by one- step quantum operation in a driven circuit quantum electrodyna.mics （QED） system. Our proposal is based on a unitary evolution exp[-iλSx^2], with Sx being the collective spin operator in x direction and A a controllable parameter, induced by driving the resonator. The quantum operation avoids resonator-field decay and may achieve the GHZ states with ideal success probability. The feasibility with the experimentally-demonstrated circuit QED system is also discussed.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 National Fundamental Research Program of China(Grant No.2011cba00200)the National Natural Science Foundation of China(Grant No.11274295)the Doctor Foundation of Education Ministry of China(Grant No.20113402110059)
文摘We theoretically study the system of a superconducting transmission line resonator coupled to two interacting super- conducting flux qubits. It is shown that under certain conditions the resonator mode can be tuned to two-photon resonance between the ground state and the highest excited state while the middle excited states are far-off resonance. Furthermore, we study the steady-state properties of the flux qubits and resonator, such as the photon statistics, the spectrum and squeezing of the resonator, and demonstrate that two-photon laser can be implemented with current experimental technology.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10775048 and 11075050)the National Basic Research Program of China (Grant No. 2007CB925204)the Education Department of Hunan Province,China (GrantNo. 08W012)
文摘We propose a scheme to enable a controllable cross-Kerr interaction between microwave photons in a circuit quantum electrodynamics （QED） system. In this scheme we use two transmission-line resonators （TLRs） and one superconducting quantum interference device （SQUID） type charge qubit, which acts as an artificial atom. It is shown that in the dispersive regime of the eircuit-QED system, a controllable cross-Kerr interaction can be obtained by properly preparing the initial state of the qubit, and a large cross-phase shift between two microwave fields in the two TLRs can then be reached. Based on this cross-Kerr interaction, we show how to create a macroscopic entangled state between the two TLRs.
基金Project supported by the National Natural Science Foundation of China(Grant No.61871234)sponsored by NUPTSF(Grant Nos.NY218097 and NY220178)。
文摘We propose a scheme to fast prepare the three-qubit W state via superadiabatic-based shortcuts in a circuit quantumelectrodynamics (circuit QED) system. We derive the effective Hamiltonian to suppress the unwanted transitions betweendifferent eigenstates by counterdiabatic driving, and obtain the W state with high-fidelity based on the superadiabaticpassage. The numerical simulation results demonstrate that the proposed scheme can accelerate the evolution, and is moreefficient than that with the adiabatic passage. In addition, the proposed scheme is robust to the decoherence caused by theresonator decay and qubit relaxation, and does not need additional parameters, which could be feasible in experiment.
基金Project supported by the National Natural Science Foundation of China(Grant No.11264015)
文摘We demonstrate the controllable generation of multi-photon Fock states in circuit quantum electrodynamics （circuit QED）. The external bias flux regulated by a counter can effectively adjust the bias time on each superconducting flux qubit so that each flux qubit can pass in turn through the circuit cavity and thereby avoid the effect of decoherence. We further investigate the quantum correlation dynamics of coupling superconducting qubits in a Fock state. The results reveal that the lower the photon number of the light field in the number state, the stronger the interaction between qubits is, then the more beneficial to maintaining entanglement between qubits it will be.
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Supported by the National Science Foundation of China under Grant Nos. 11074070, 10774042, and 10774163the Nature Science Foundation of Hunan Province under Grant No. 09JJ3121+1 种基金the Key Project of Science and Technology of Hunan Province under Grant Nos. 2010FJ2005 and 2008FJ4217the NKBRSFC under Grant No. 2010CB922904
文摘We give the brief review on the related definition of the geometric phase independent of specific physical system based on the displacement opreator and the sqeezed operator, then show how the displacement operator and the squeezed operator can induce the general geometric phase. By means of the displacement operator and the squeezed operator concerning the circuit cavity mode state along a closed path in the phase space, we discuss specifically how to implement a two-qubit geometric phase gate in circuit quantum electrodynamics with both single photon interaction and two-photon interaction between the superconducting qubits and the circuit cavity modes. The experimental feasibility is discussed in detail.
基金Supported by the National Science Foundation of China under Grant Nos.11074070,10774042,and 10774163the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institute of Hunan Province+1 种基金the Key Project of Science and Technology of Hunan Province under Grant No.2010FJ2005the NKBRSFC under Grant No.2010CB922904
文摘We study the influence of multi-photon processes on the geometric quantum computation in the systems of superconducting qubits based on the displacement-like and the general squeezed operator methods. As an example, we focus on the question about how to implement a two-qubit geometric phase gate using superconducting circuit quantum electrodynamics with both single- and two-photon interaction between the qubits and the cavity modes. We find that the multiphoton processes are not only controllable but also improve the gating speed. The comparison with other physical systems and experimental feasibility are discussed in detail.
基金the National Natural Science Foun-dation of China(Grant Nos.92265113,12074368,12304560,and 12034018)China Postdoctoral Science Foundation(Grant Nos.BX20220281 and 2023M733408).
文摘Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation.To satisfy the connectivity requirements and reduce the lithographic complexity,utilizing the qubit array structure and the circuit quantum electrodynamics(cQED)architecture together is expected to be a feasible scaling scheme.A triple-quantum dot(TQD)coupled with a superconducting resonator is regarded as a basic cell to demonstrate this extension scheme.In this article,we investigate a system consisting of a silicon TQD and a high-impedance TiN coplanar waveguide(CPW)resonator.The TQD can couple to the resonator via the right double-quantum dot(RDQD),which reaches the strong coupling regime with a charge–photon coupling strength of g0/(2p)=175 MHz.Moreover,we illustrate the high tunability of the TQD through the characterization of stability diagrams,quadruple points(QPs),and the quantum cellular automata(QCA)process.Our results contribute to fostering the exploration of silicon-based qubit integration.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974336 and 12304401)the National Key R&D Program of China(Grant No.2017YFA0304100)+1 种基金the Key Project of Natural Science Research in Universities of Anhui Province(Grant No.KJ2021A1107)the Scientific Research Foundation of Suzhou University(Grant Nos.2020BS006 and 2021XJPT18).
文摘Spin qubits and superconducting qubits are promising candidates for realizing solid-state quantum information processors.Designing a hybrid architecture that combines the advantages of different qubits on the same chip is a highly desirable but challenging goal.Here we propose a hybrid architecture that utilizes a high-impedance SQUID array resonator as a quantum bus,thereby coherently coupling different solid-state qubits.We employ a resonant exchange spin qubit hosted in a triple quantum dot and a superconducting transmon qubit.Since this hybrid system is highly tunable,it can operate in a dispersive regime,where the interaction between the different qubits is mediated by virtual photons.By utilizing such interactions,entangling gate operations between different qubits can be realized in a short time of 30 ns with a fidelity of up to 96.5%under realistic parameter conditions.Further utilizing this interaction,remote entangled state between different qubits can be prepared and is robust to perturbations of various parameters.These results pave the way for exploring efficient fault-tolerant quantum computation on hybrid quantum architecture platforms.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10874142 and 90921010
文摘We propose an efficient scheme to generate multiqubit Greenberger-ttorne--Zeilinger （GHZ） states by one- step quantum operation in a driven circuit quantum electrodyna.mics （QED） system. Our proposal is based on a unitary evolution exp[-iλSx^2], with Sx being the collective spin operator in x direction and A a controllable parameter, induced by driving the resonator. The quantum operation avoids resonator-field decay and may achieve the GHZ states with ideal success probability. The feasibility with the experimentally-demonstrated circuit QED system is also discussed.
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.
