Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Chinese Physics Letters

Manipulating Quantum State in Superconducting Dressed-State Systems

Feng‐Yang Zhang, Pei Pei, Chong Li, He‐Shan Song

Published Dec 1, 2011• 3 citations
Publisher

Abstract

We construct a novel Λ-type system via the dressed states formed by the coupling between a superconducting qubit and a transmission line resonator (TLR). Compared with the conventional three-level structure, our model averts the decay of excited states. We choose the two lowest energy dressed states as the logical states. The single qubit quantum gate can be realized by the adiabatic passage and three-step operation method, respectively. Based on realistic parameters, the feasibility of the adiabatic passage method is discussed. Also, we calculate the fidelity (0.9996) of realizing the single qubit gate with the three-step operation method.

DOI
10.1088/0256-307x/28/12/120304

Related papers

Quantum phase gate on a single superconducting Λ-type three-level and two superconducting resonators

Liu Chao, Wu Yun-Wen

Quantum phase gate is a necessary quantum component for quantum coding and quantum computing. Compared with the traditional gate circuit, quantum phase gate has the characteristics of unitarity and reversibility. Therefore, we construct a model of mutual coupling between a single Λ -type three-level atom and two superconducting resonators, which is connected by a capacitor. By separately controlling the disconnection time and connection time of the two superconducting resonators in the model as well as by controlling the magnetic flux of the superconducting quantum interference device (SQUID) to make a certain transition energy level of the Λ -type three-level atom equal the relevant resonance energy level, the interaction between the two levels can be achieved and the system can be manipulated. Afterwards, we propose four control schemes for implementing the controlled-Z gate through a three-step operation, and two operation schemes for implementing swap gate through a four-step operation. At the same time, the numerical simulations of fidelity are implemented for the first operation scheme for controlling the Z-gate. The results of fidelity discussion show that the fidelity of this scheme is 96.67% through the running time of 20.83 ns, thus it proves that this scheme is theoretically feasible. The increase in the three attenuation parameters, i.e., attenuation rate, relaxation rate, and phase shift ratio, will reduce the fidelity of the system, while the increase in coupling strength will cut down the time of system operation, thus reducing the influence of attenuation parameters and improving the system fidelity.In this paper we present a quantum phase gate scheme in which two superconducting resonators and a Λ -type three-level atom are coupled with two capacitors. Since the experimental setup is simplified, it is important to reduce the coherence between devices. In addition, the solution has no restriction on the strength of the classic pulse principally, through which the system operates faster and the fidelity of the phase gate is improved effectively.

Acta Physica Sinica•Jan 1, 2018•1 citation

REALIZATION OF FAST QUANTUM INFORMATION TRANSFER AND ENTANGLEMENT WITH SUPERCONDUCTING FLUX QUBITS COUPLED TO A RESONATOR

Yawei Wang, Shaoyan Gao, Aiping Fang +2 more

We propose a scheme of realization of fast quantum information transfer and two-qubit entangled state with two different superconducting flux qubits coupled to a single-mode resonator. In this approach, the two lowest levels of each Λ-type flux qubit serve as the logical states and a higher-energy intermediate level is used as the gate manipulation. This proposal does not require equal device parameters for the two flux qubits that is extremely difficult to achieve experimentally. In addition, neither a second-order detuning nor auxiliary qubits are required in this scheme. Moreover, there is no need to change the Rabi frequencies to satisfy the adiabatic passage. Therefore, the operation time can be shortened to 20–30 ns, which is faster by one order of magnitude compared to the schemes employing the second-order detuning technique.

International Journal of Quantum Information•Jun 1, 2013•1 citation

Quantum manipulation of low-frequency fluctuators by superconducting resonator

Lin Tian, Kurt A. Jacobs

Two-level system fluctuators in superconducting devices have demonstrated coherent coupling with superconducting qubits. Here, we show that universal quantum logic gates can be realized in these two-level systems solely by tuning a superconducting resonator in which they are imbedded. Because of the large energy separation between the fluctuators, conventional gate schemes in the cavity QED approach that are widely used for solid-state qubits cannot be directly applied to the fluctuators. We study a scheme to perform the gate operations by exploiting the controllability of the superconducting resonator with realistic parameters. Numerical simulation that takes into account the decay of the resonator mode shows that the quantum logic gates can be realized with high fidelity at moderate resonator decay rate. The quantum logic gates can also be realized between fluctuators inside different Josephson junctions that are connected by a superconducting loop. Our scheme can be applied to explore the coupling between two-level system fluctuators and superconducting resonators as well as the coherent properties of the fluctuators.

arXiv:0903.0193•Physical Review B•Apr 1, 2009•8 citations

A proposal for implementing ann-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity QED

Chui‐Ping Yang

We present a method for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity quantum electrodynamics. The two logical states of a qubit are represented by the two lowest levels of each system while a higher energy level is used for the gate implementation. The method operates essentially by preparing a W state conditioned on the states of the control qubits, creating a single photon in the cavity mode, and then performing an arbitrary rotation on the states of the target qubit with the assistance of the cavity photon. It is interesting to note that the basic operational steps for implementing the proposed gate do not increase with the number of qubits n, and the gate operation time decreases as the number of qubits increases. This proposal is quite general, and can be applied to various types of superconducting devices in a cavity or coupled to a resonator.

arXiv:1105.1496•Journal of Physics Condensed Matter•May 19, 2011•4 citations

Dressed-state realization of the transition from electromagnetically induced transparency to Autler-Townes splitting in superconducting circuits

Hai‐Chao Li, Guo-Qin Ge, Haiyang Zhang

We investigate electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) in a driven three-level superconducting artificial system which is a dressed-state system resulting from the coupling of a superconducting charge qubit (an artificial atom) and a transmission line resonator. In the frame of the dressed-state approach and steady-state approximation, we study the linear absorption of the dressed artificial system to a weak probe signal in depth. In light of the spectrum-decomposition method and some other restrictions, we obtain the explicit conditions for the dressed-state realization of EIT and ATS and present a corresponding "phase diagram". In contrast to usual bare systems, these conditions given in the dressed system have an extra dependency on the qubit-resonator parameters. And by varying the qubit's Josephson coupling energy we demonstrate a transition from EIT to ATS.

Optics Express•Apr 9, 2015•14 citations

Quantum logical gates with four-level superconducting quantum interference devices coupled to a superconducting resonator

Xiao-Ling He, Chui‐Ping Yang, Li Sheng +2 more

We propose a way for realizing a two-qubit controlled phase gate with superconducting quantum interference devices (SQUIDs) coupled to a superconducting resonator. In this proposal, the two lowest levels of each SQUID serve as the logical states and two intermediate levels of each SQUID are used for the gate realization. We show that neither adjustment of SQUID level spacings during the gate operation nor uniformity in SQUID parameters is required by this proposal. In addition, this proposal does not require the adiabatic passage or a second-order detuning and thus the gate is much faster.

arXiv:1002.1342•Physical Review A•Aug 4, 2010•14 citations
We construct a novel Λ-type system via the dressed states formed by the coupling between a superconducting qubit and a transmission line resonator (TLR). Compared with the conventional three-level structure, our model averts the decay of excited states. We choose the two lowest energy dressed states as the logical states. The single qubit quantum gate can be realized by the adiabatic passage and three-step operation method, respectively. Based on realistic parameters, the feasibility of the adiabatic passage method is discussed. Also, we calculate the fidelity (0.9996) of realizing the single qubit gate with the three-step operation method.
Quantum phase gate is a necessary quantum component for quantum coding and quantum computing. Compared with the traditional gate circuit, quantum phase gate has the characteristics of unitarity and reversibility. Therefore, we construct a model of mutual coupling between a single Λ -type three-level atom and two superconducting resonators, which is connected by a capacitor. By separately controlling the disconnection time and connection time of the two superconducting resonators in the model as well as by controlling the magnetic flux of the superconducting quantum interference device (SQUID) to make a certain transition energy level of the Λ -type three-level atom equal the relevant resonance energy level, the interaction between the two levels can be achieved and the system can be manipulated. Afterwards, we propose four control schemes for implementing the controlled-Z gate through a three-step operation, and two operation schemes for implementing swap gate through a four-step operation. At the same time, the numerical simulations of fidelity are implemented for the first operation scheme for controlling the Z-gate. The results of fidelity discussion show that the fidelity of this scheme is 96.67% through the running time of 20.83 ns, thus it proves that this scheme is theoretically feasible. The increase in the three attenuation parameters, i.e., attenuation rate, relaxation rate, and phase shift ratio, will reduce the fidelity of the system, while the increase in coupling strength will cut down the time of system operation, thus reducing the influence of attenuation parameters and improving the system fidelity.In this paper we present a quantum phase gate scheme in which two superconducting resonators and a Λ -type three-level atom are coupled with two capacitors. Since the experimental setup is simplified, it is important to reduce the coherence between devices. In addition, the solution has no restriction on the strength of the classic pulse principally, through which the system operates faster and the fidelity of the phase gate is improved effectively.
We propose a scheme of realization of fast quantum information transfer and two-qubit entangled state with two different superconducting flux qubits coupled to a single-mode resonator. In this approach, the two lowest levels of each Λ-type flux qubit serve as the logical states and a higher-energy intermediate level is used as the gate manipulation. This proposal does not require equal device parameters for the two flux qubits that is extremely difficult to achieve experimentally. In addition, neither a second-order detuning nor auxiliary qubits are required in this scheme. Moreover, there is no need to change the Rabi frequencies to satisfy the adiabatic passage. Therefore, the operation time can be shortened to 20–30 ns, which is faster by one order of magnitude compared to the schemes employing the second-order detuning technique.
Two-level system fluctuators in superconducting devices have demonstrated coherent coupling with superconducting qubits. Here, we show that universal quantum logic gates can be realized in these two-level systems solely by tuning a superconducting resonator in which they are imbedded. Because of the large energy separation between the fluctuators, conventional gate schemes in the cavity QED approach that are widely used for solid-state qubits cannot be directly applied to the fluctuators. We study a scheme to perform the gate operations by exploiting the controllability of the superconducting resonator with realistic parameters. Numerical simulation that takes into account the decay of the resonator mode shows that the quantum logic gates can be realized with high fidelity at moderate resonator decay rate. The quantum logic gates can also be realized between fluctuators inside different Josephson junctions that are connected by a superconducting loop. Our scheme can be applied to explore the coupling between two-level system fluctuators and superconducting resonators as well as the coherent properties of the fluctuators.
We present a method for implementing an n-qubit controlled-rotation gate with three-level superconducting qubit systems in cavity quantum electrodynamics. The two logical states of a qubit are represented by the two lowest levels of each system while a higher energy level is used for the gate implementation. The method operates essentially by preparing a W state conditioned on the states of the control qubits, creating a single photon in the cavity mode, and then performing an arbitrary rotation on the states of the target qubit with the assistance of the cavity photon. It is interesting to note that the basic operational steps for implementing the proposed gate do not increase with the number of qubits n, and the gate operation time decreases as the number of qubits increases. This proposal is quite general, and can be applied to various types of superconducting devices in a cavity or coupled to a resonator.
We investigate electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) in a driven three-level superconducting artificial system which is a dressed-state system resulting from the coupling of a superconducting charge qubit (an artificial atom) and a transmission line resonator. In the frame of the dressed-state approach and steady-state approximation, we study the linear absorption of the dressed artificial system to a weak probe signal in depth. In light of the spectrum-decomposition method and some other restrictions, we obtain the explicit conditions for the dressed-state realization of EIT and ATS and present a corresponding "phase diagram". In contrast to usual bare systems, these conditions given in the dressed system have an extra dependency on the qubit-resonator parameters. And by varying the qubit's Josephson coupling energy we demonstrate a transition from EIT to ATS.
We propose a way for realizing a two-qubit controlled phase gate with superconducting quantum interference devices (SQUIDs) coupled to a superconducting resonator. In this proposal, the two lowest levels of each SQUID serve as the logical states and two intermediate levels of each SQUID are used for the gate realization. We show that neither adjustment of SQUID level spacings during the gate operation nor uniformity in SQUID parameters is required by this proposal. In addition, this proposal does not require the adiabatic passage or a second-order detuning and thus the gate is much faster.