Two-qubit gate using conditional driving for highly detuned Kerr-nonlinear parametric oscillators

Abstract

A Kerr-nonlinear parametric oscillator (KPO) is one of the promising devices to realize qubits for universal quantum computing. The KPO can stabilize two coherent states with opposite phases, yielding a quantum superposition called a Schrödinger cat state. Universal quantum computing with KPOs requires three kinds of quantum gates: $R_z,R_x$, and $R_{zz}$ gates. We theoretically propose a two-qubit gate $R_{zz}$ for highly detuned KPOs. In the proposed scheme, we add another two-photon drive for the first KPO. This leads to the $R_{zz}$ gate based on the driving of the second KPO depending on the first-KPO state, which we call "conditional driving." First, we perform simulations using a conventional KPO Hamiltonian derived from a superconducting-circuit model under some approximations and evaluate the gate fidelity. Next, we also perform numerical simulations of the two-qubit gate using the superconducting-circuit model without the approximations. The simulation results indicate that two-qubit gates can be implemented with high fidelity ($>99.9\%$) for rotation angles required for universality.

9 pages, 7 figures

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Cited by in corpus (11)

• The squeezed Kerr oscillator: spectral kissing and phase-flip robustness
• Observation and manipulation of quantum interference in a superconducting Kerr parametric oscillator
• Two-photon driven Kerr quantum oscillator with multiple spectral degeneracies
• Entangling Schrödinger's cat states by bridging discrete- and continuous-variable encoding
• Control of the $ZZ$ coupling between Kerr-cat qubits via transmon couplers
• Genuine non-Gaussian entanglement of light and quantum coherence for an atom from noisy multiphoton spin-boson interactions
• Fast elementary gates for universal quantum computation with Kerr parametric oscillator qubits
• Unraveling the switching dynamics in a quantum double-well potential
• Residual-$ZZ$-coupling suppression and fast two-qubit gate for Kerr-cat qubits based on level-degeneracy engineering
• Quantum annealing in capacitively coupled Kerr parametric oscillators using frequency-chirped drives
• High-performance conditional-driving gate for Kerr parametric oscillator qubits