Entanglement of superconducting qubits via microwave fields: classical and quantum regimes

TL;DR

This paper investigates how two superconducting qubits can be entangled using microwave fields in both classical and quantum regimes, providing methods for quantum gate implementation and entanglement generation.

Contribution

It introduces analytical and numerical methods for entangling superconducting qubits via microwave fields, including effective Hamiltonians and pulse sequences for quantum gates.

Findings

Classical fields enable CNOT gate construction.

Quantum fields at low power produce multiparticle entanglement.

Maximally entangled two-qubit states can be achieved.

Abstract

We study analytically and numerically the problem of two qubits with fixed coupling irradiated with quantum or classical fields. In the classical case, we derive an effective Hamiltonian, and construct composite pulse sequences leading to a CNOT gate. In the quantum case, we show that qubit-qubit-photon multiparticle entanglement and maximally entangled two-qubit state can be obtained by driving the system at very low powers (one quanta of excitation). Our results can be applied to a variety of systems of two superconducting qubits coupled to resonators.