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

Bulletin of the American Physical Society

Manipulating Kerr effects in a superconducting cavity via a superconducting qubit

Victor V. Albert, Gerhard Kirchmair, Brian Vlastakis, Zaki Leghtas, Mazyar Mirrahimi, S. M. Girvin, Robert J. Schoelkopf, Liang Jiang

Published Mar 21, 2013• 0 citations
OpenAlex

Related papers

Coupling two superconducting qubits via a cavity

Johannes Majer, S. M. Girvin, Robert J. Schoelkopf

Bulletin of the American Physical Society•Mar 6, 2007•0 citations

Designing Kerr interactions using multiple superconducting qubit types in a single circuit

Matthew Elliott, Jaewoo Joo, Eran Ginossar

The engineering of Kerr interactions is of great interest for processing quantum information in multipartite quantum systems and for investigating many-body physics in a complex cavity-qubit network. We study how coupling multiple different types of superconducting qubits to the same cavity modes can be used to modify the self- and cross-Kerr effects acting on the cavities and demonstrate that this type of architecture could be of significant benefit for quantum technologies. Using both analytical perturbation theory results and numerical simulations, we first show that coupling two superconducting qubits with opposite anharmonicities to a single cavity enables the effective self-Kerr interaction to be diminished, while retaining the number splitting effect that enables control and measurement of the cavity field. We demonstrate that this reduction of the self-Kerr effect can maintain the fidelity of coherent states and generalised Schrödinger cat states for much longer than typical coherence times in realistic devices. Next, we find that the cross-Kerr interaction between two cavities can be modified by coupling them both to the same pair of qubit devices. When one of the qubits is tunable in frequency, the strength of entangling interactions between the cavities can be varied on demand, forming the basis for logic operations on the two modes. Finally, we discuss the feasibility of producing an array of cavities and qubits where intermediary and on-site qubits can tune the strength of self- and cross-Kerr interactions across the whole system. This architecture could provide a way to engineer interesting many-body Hamiltonians and be a useful platform for quantum simulation in circuit quantum electrodynamics.

arXiv:1709.04026•New Journal of Physics•Oct 10, 2017•18 citations

Fluxonium as a Control Qubit for Bosonic Quantum Information

Ke Nie, J. Nofear Bradford, Supriya Mandal +3 more

Bosonic codes in superconducting resonators are a hardware-efficient avenue for quantum error correction and benefit from the inherent bias toward relaxation errors provided by long-lived cavities compared to typical superconducting qubits. The required coupling to an ancillary control qubit, however, can negate these benefits by inducing highly detrimental effects such as excess decoherence and undesired nonlinearities. This is exemplified by the typically employed transmon qubit that imposes limits on cavity operations due to its finite lifetime as well as the inevitably induced self-Kerr nonlinearity. An important question is thus whether a cavity-qubit coupling can be realized that offers readout and control capabilities without spoiling the cavity. Here, motivated by its long lifetime and design flexibility of its Hamiltonian, we experimentally investigate the fluxonium as a control qubit for superconducting cavities. We couple a fluxonium qubit to a superconducting resonator in the strong-dispersive regime and use it to measure the coherence and flux-tunable inherited nonlinearities of the resonator. We then demonstrate quantum control of the oscillator by preparing and characterizing resonator Fock states and their superpositions, with fidelities limited by resonator decay in our planar prototype device. Finally, we show that the fluxonium can realize cavity-couplings that eliminate undesirable cavity nonlinearities and reach regimes of suppressed self-Kerr that are inaccessible to transmon-based devices. Our results thus demonstrate the potential of the fluxonium as a high-performance bosonic control qubit for superconducting cavities that can outperform existing transmon-based architectures.

arXiv:2505.23641•PRX Quantum•Feb 17, 2026•2 citations

Superconducting Qubits in Quantum Electronics

Shreya, Bhawna, Sukhvir Singh +1 more

Springer eBooks•Jan 1, 2026•1 citation

Single Photon Kerr Effect in Circuit QED

Gerhard Kirchmair

The recent development of a 3D architecture for superconducting circuits has dramatically increased the coherence time of qubits and cavities. This allows us to reach the single-photon Kerr regime in circuit QED, where the interaction strength between individual photons in a waveguide cavity exceeds the loss rate. Here, using a two-cavity/single-qubit system, we engineer an artificial Kerr medium that enters this regime and allows the observation of new quantum effects. We realize a Gedankenexperiment [1] proposed by Yurke and Stoler, in which the collapse and revival of a coherent state can be observed. During this evolution non-classical superpositions of coherent states, i.e. multi-component Schrodinger cat states, are formed. We visualize this evolution by measuring the Husimi Q-function and confirm the non-classical properties of these transient states by Wigner tomography.

Bulletin of the American Physical Society•Mar 6, 2014•0 citations

Proposal for a cavity based superconducting qubit

Andrei Vrajitoarea, Jens Koch, Andrew Houck

Bulletin of the American Physical Society•Mar 16, 2016•0 citations
The engineering of Kerr interactions is of great interest for processing quantum information in multipartite quantum systems and for investigating many-body physics in a complex cavity-qubit network. We study how coupling multiple different types of superconducting qubits to the same cavity modes can be used to modify the self- and cross-Kerr effects acting on the cavities and demonstrate that this type of architecture could be of significant benefit for quantum technologies. Using both analytical perturbation theory results and numerical simulations, we first show that coupling two superconducting qubits with opposite anharmonicities to a single cavity enables the effective self-Kerr interaction to be diminished, while retaining the number splitting effect that enables control and measurement of the cavity field. We demonstrate that this reduction of the self-Kerr effect can maintain the fidelity of coherent states and generalised Schrödinger cat states for much longer than typical coherence times in realistic devices. Next, we find that the cross-Kerr interaction between two cavities can be modified by coupling them both to the same pair of qubit devices. When one of the qubits is tunable in frequency, the strength of entangling interactions between the cavities can be varied on demand, forming the basis for logic operations on the two modes. Finally, we discuss the feasibility of producing an array of cavities and qubits where intermediary and on-site qubits can tune the strength of self- and cross-Kerr interactions across the whole system. This architecture could provide a way to engineer interesting many-body Hamiltonians and be a useful platform for quantum simulation in circuit quantum electrodynamics.
Bosonic codes in superconducting resonators are a hardware-efficient avenue for quantum error correction and benefit from the inherent bias toward relaxation errors provided by long-lived cavities compared to typical superconducting qubits. The required coupling to an ancillary control qubit, however, can negate these benefits by inducing highly detrimental effects such as excess decoherence and undesired nonlinearities. This is exemplified by the typically employed transmon qubit that imposes limits on cavity operations due to its finite lifetime as well as the inevitably induced self-Kerr nonlinearity. An important question is thus whether a cavity-qubit coupling can be realized that offers readout and control capabilities without spoiling the cavity. Here, motivated by its long lifetime and design flexibility of its Hamiltonian, we experimentally investigate the fluxonium as a control qubit for superconducting cavities. We couple a fluxonium qubit to a superconducting resonator in the strong-dispersive regime and use it to measure the coherence and flux-tunable inherited nonlinearities of the resonator. We then demonstrate quantum control of the oscillator by preparing and characterizing resonator Fock states and their superpositions, with fidelities limited by resonator decay in our planar prototype device. Finally, we show that the fluxonium can realize cavity-couplings that eliminate undesirable cavity nonlinearities and reach regimes of suppressed self-Kerr that are inaccessible to transmon-based devices. Our results thus demonstrate the potential of the fluxonium as a high-performance bosonic control qubit for superconducting cavities that can outperform existing transmon-based architectures.
The recent development of a 3D architecture for superconducting circuits has dramatically increased the coherence time of qubits and cavities. This allows us to reach the single-photon Kerr regime in circuit QED, where the interaction strength between individual photons in a waveguide cavity exceeds the loss rate. Here, using a two-cavity/single-qubit system, we engineer an artificial Kerr medium that enters this regime and allows the observation of new quantum effects. We realize a Gedankenexperiment [1] proposed by Yurke and Stoler, in which the collapse and revival of a coherent state can be observed. During this evolution non-classical superpositions of coherent states, i.e. multi-component Schrodinger cat states, are formed. We visualize this evolution by measuring the Husimi Q-function and confirm the non-classical properties of these transient states by Wigner tomography.