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

Youth Academic Annual Conference of Chinese Association of Automation (YAC)

Generation of Schrödinger cat state in circuit QED

Gang Zhang, Ping Dong, Jian Zhou

Published May 1, 2017• 1 citation
Publisher

Abstract

An attractive scheme for generation the Schrödinger cat state is proposed in the circuit QED system with suitable driving field. By tuning the external magnetic flux properly, the qubit and cavity strong coupling can be realized insensitively to the thermal state of the cavity. Discussions show that our scheme is feasible within current experimental technology.

DOI
10.1109/yac.2017.7967475

Related papers

Nonlinear coupling and squeezing in solid-state quantum circuits

Jian Zhou, Dan-Wei Zhang, Man-Lv Peng +1 more

We propose an attractive realization of nonlinear coupling of superconducting charge qubit coupled to a transmission-line resonator. Our scheme provides a new approach to produce the strong squeezing effect via a flexible design of the superconducting qubit and mature experimental setup of circuit QED. By properly tuning the external magnetic flux, considerable squeezing can be generated. Strong coupling strength, immunity to noises and suppression of spontaneous emission make our scheme more robust and may be realized with conservative experimental parameters.

Journal of Modern Optics•Nov 1, 2013•0 citations

Schrodinger Cat States in Circuit QED

S. M. Girvin

Circuit quantum electrodynamics ('circuit QED') describes the quantum mechanics and quantum field theory of superconducting electrical circuits operating in the microwave regime near absolute zero temperature. It is the analog of cavity QED in quantum optics with the role of the atoms being played by superconducting qubits. The present lecture notes focus primarily on novel quantum states that can be produced and measured using the strong coupling between an artificial atom and one or more cavities. Of particular importance are Schrodinger cat states of photons. Despite long being considered exemplars of frail quantum superpositions that quickly decohere, such states have recently been used as the basis for quantum error correction codes which have reached the long-sought goal of enhancing the lifetime of quantum information through active quantum error correction.

arXiv:1710.03179•Oct 9, 2017•2 citations

Preparation of Entanglement and Schrödinger Cat States of Superconducting Quantum Interference Devices Qubits via Coupling to a Microwave Cavity

Wen‐Xing Yang

An alternative scheme is proposed for the generation of n-qubit W states of superconducting quantum interference devices (SQUID) in cavity QED. In this scheme, Raman coupling of two lower flux states of SQUID system is achieved via a microwave pulse and the cavity mode. Conditioned on no photon leakage from the cavity, the n-qubit W state can be generated whether the effective coupling parameters of the SQUID to cavity mode and classical microwave fields are the same or different. Our strictly numerical simulations of the time evolution of the system including decay show that the success probability of our scheme is almost unity and the interaction time is on the order of 10 −9 s. The scheme can also be used to generate the Schrödinger cat states of multi-SQUID.

Communications in Theoretical Physics•Mar 1, 2008•1 citation

Measurement-induced generation of Schrödinger cat states in cavity QED

Tong Wang, Peng-Fei Wei, Hai-Jun Xing +1 more

Schrödinger cat states, representing coherent superpositions of macroscopically distinguishable states, are indispensable nonclassical resources for continuous-variable quantum information processing. Existing generation protocols typically rely on strong nonlinear interactions, complicated control techniques, or engineered dissipation, posing challenges for experimental implementation. Here, we propose a simple measurement-based protocol for generating Schrödinger cat states in a cavity-QED system by combining coherent driving, dispersive atom--cavity interactions, and atomic postselection. The atom--cavity interaction establishes coherent correlations between the atomic and photonic degrees of freedom, while the subsequent atomic postselection projects the cavity field onto a non-Gaussian superposition state with pronounced Wigner negativity. Numerical simulations based on the Lindblad master equation show that the generated Schrödinger cat states remain robust against moderate cavity dissipation. Our results demonstrate that conditional atomic measurements provide an effective and experimentally accessible approach for preparing nonclassical cavity states without relying on strong optical nonlinearities or engineered dissipation.

quant-pharXiv:2608.04578•Aug 6, 2026•0 citations

Wiring Up Quantum Systems: Circuit QED with Artificial Atoms and Microwave Photons

S. M. Girvin

A revolution is underway in the construction of ‘artificial atoms’ out of superconducting electrical circuits. ‘Circuit QED’ permits strong-coupling non-linear optics at the single-photon level and gives an architecture for novel quantum information processing. The dispersive coupling between a qubit and a microwave cavity can be orders of magnitude larger than the line widths of both qubit and cavity. This yields a new ‘quantum toolbox’ which permits arbitrary control of the entangled quantum state of the system. For example one can flip the state of the qubit conditioned on there being exactly n photons in the cavity or one can displace the cavity oscillation amplitude conditioned on the state of the qubit. Using these tools it is now possible to create large ‘Schrödinger cat’ states containing more than 100 photons. An introduction to circuit QED and a review of recent experimental results will be presented.

The Rochester Conferences on Coherence and Quantum Optics and the Quantum Information and Measurement meeting•Jan 1, 2013•0 citations

Schrödinger cat states in circuit QED

S. M. Girvin

Circuit quantum electrodynamics (‘circuit QED’) describes the quantum mechanics and quantum optics of superconducting electrical circuits operating in the microwave regime near absolute zero temperature. It is the analog of cavity QED in quantum optics with the role of the atoms being played by superconducting qubits. The present lecture notes present a brief overview of circuit QED and then focus on some of the novel quantum states that can be produced and measured (via photon number parity and the Wigner function) using the strong coupling between an artificial atom and one or more cavities. Of particular importance are Schrödinger cat states of photons. Despite long being considered exemplars of frail quantum superpositions that quickly decohere, such states have recently been used as the basis for quantum error correction codes which have reached the long-sought goal of enhancing the lifetime of quantum information through active quantum error correction.

Oxford University Press eBooks•May 16, 2019•2 citations
An attractive scheme for generation the Schrödinger cat state is proposed in the circuit QED system with suitable driving field. By tuning the external magnetic flux properly, the qubit and cavity strong coupling can be realized insensitively to the thermal state of the cavity. Discussions show that our scheme is feasible within current experimental technology.
We propose an attractive realization of nonlinear coupling of superconducting charge qubit coupled to a transmission-line resonator. Our scheme provides a new approach to produce the strong squeezing effect via a flexible design of the superconducting qubit and mature experimental setup of circuit QED. By properly tuning the external magnetic flux, considerable squeezing can be generated. Strong coupling strength, immunity to noises and suppression of spontaneous emission make our scheme more robust and may be realized with conservative experimental parameters.
Circuit quantum electrodynamics ('circuit QED') describes the quantum mechanics and quantum field theory of superconducting electrical circuits operating in the microwave regime near absolute zero temperature. It is the analog of cavity QED in quantum optics with the role of the atoms being played by superconducting qubits. The present lecture notes focus primarily on novel quantum states that can be produced and measured using the strong coupling between an artificial atom and one or more cavities. Of particular importance are Schrodinger cat states of photons. Despite long being considered exemplars of frail quantum superpositions that quickly decohere, such states have recently been used as the basis for quantum error correction codes which have reached the long-sought goal of enhancing the lifetime of quantum information through active quantum error correction.
An alternative scheme is proposed for the generation of n-qubit W states of superconducting quantum interference devices (SQUID) in cavity QED. In this scheme, Raman coupling of two lower flux states of SQUID system is achieved via a microwave pulse and the cavity mode. Conditioned on no photon leakage from the cavity, the n-qubit W state can be generated whether the effective coupling parameters of the SQUID to cavity mode and classical microwave fields are the same or different. Our strictly numerical simulations of the time evolution of the system including decay show that the success probability of our scheme is almost unity and the interaction time is on the order of 10 −9 s. The scheme can also be used to generate the Schrödinger cat states of multi-SQUID.
Schrödinger cat states, representing coherent superpositions of macroscopically distinguishable states, are indispensable nonclassical resources for continuous-variable quantum information processing. Existing generation protocols typically rely on strong nonlinear interactions, complicated control techniques, or engineered dissipation, posing challenges for experimental implementation. Here, we propose a simple measurement-based protocol for generating Schrödinger cat states in a cavity-QED system by combining coherent driving, dispersive atom--cavity interactions, and atomic postselection. The atom--cavity interaction establishes coherent correlations between the atomic and photonic degrees of freedom, while the subsequent atomic postselection projects the cavity field onto a non-Gaussian superposition state with pronounced Wigner negativity. Numerical simulations based on the Lindblad master equation show that the generated Schrödinger cat states remain robust against moderate cavity dissipation. Our results demonstrate that conditional atomic measurements provide an effective and experimentally accessible approach for preparing nonclassical cavity states without relying on strong optical nonlinearities or engineered dissipation.
A revolution is underway in the construction of ‘artificial atoms’ out of superconducting electrical circuits. ‘Circuit QED’ permits strong-coupling non-linear optics at the single-photon level and gives an architecture for novel quantum information processing. The dispersive coupling between a qubit and a microwave cavity can be orders of magnitude larger than the line widths of both qubit and cavity. This yields a new ‘quantum toolbox’ which permits arbitrary control of the entangled quantum state of the system. For example one can flip the state of the qubit conditioned on there being exactly n photons in the cavity or one can displace the cavity oscillation amplitude conditioned on the state of the qubit. Using these tools it is now possible to create large ‘Schrödinger cat’ states containing more than 100 photons. An introduction to circuit QED and a review of recent experimental results will be presented.
Circuit quantum electrodynamics (‘circuit QED’) describes the quantum mechanics and quantum optics of superconducting electrical circuits operating in the microwave regime near absolute zero temperature. It is the analog of cavity QED in quantum optics with the role of the atoms being played by superconducting qubits. The present lecture notes present a brief overview of circuit QED and then focus on some of the novel quantum states that can be produced and measured (via photon number parity and the Wigner function) using the strong coupling between an artificial atom and one or more cavities. Of particular importance are Schrödinger cat states of photons. Despite long being considered exemplars of frail quantum superpositions that quickly decohere, such states have recently been used as the basis for quantum error correction codes which have reached the long-sought goal of enhancing the lifetime of quantum information through active quantum error correction.