Observing pure effects of counter-rotating terms without ultrastrong coupling: A single photon can simultaneously excite two qubits

Abstract

The coherent process that a single photon simultaneously excites two qubits has recently been theoretically predicted by [https://link.aps.org/doi/10.1103/PhysRevLett.117.043601 {Phys. Rev. Lett. 117, 043601 (2016)}]. We propose a different approach to observe a similar dynamical process based on a superconducting quantum circuit, where two coupled flux qubits longitudinally interact with the same resonator. We show that this simultaneous excitation of two qubits (assuming that the sum of their transition frequencies is close to the cavity frequency) is related to the counter-rotating terms in the dipole-dipole coupling between two qubits, and the standard rotating-wave approximation is not valid here. By numerically simulating the adiabatic Landau-Zener transition and Rabi-oscillation effects, we clearly verify that the energy of a single photon can excite two qubits via higher-order transitions induced by the longitudinal couplings and the counter-rotating terms. Compared with previous studies, the coherent dynamics in our system only involves one intermediate state and, thus, exhibits a much faster rate. We also find transition paths which can interfere. Finally, by discussing how to control the two longitudinal-coupling strengths, we find a method to observe both constructive and destructive interference phenomena in our system.

11 pages, 6 figures

References in corpus (17)

• Beyond the Jaynes-Cummings model: circuit QED in the ultrastrong coupling regime
• Microwave photonics with superconducting quantum circuits
• Superconducting Circuits and Quantum Information
• Observation of the Bloch-Siegert Shift in a Qubit-Oscillator System in the Ultrastrong Coupling Regime
• Deep Strong Coupling Regime of the Jaynes-Cummings model
• Generalized rotating-wave approximation for arbitrarily large coupling
• Spectroscopy on two coupled flux qubits
• Low-Disorder Microwave Cavity Lattices for Quantum Simulation with Photons
• Tuning the Gap of a Superconducting Flux Qubit
• Strong Coupling of a Quantum Oscillator to a Flux Qubit at its Symmetry Point
• Nonclassical Radiation from Thermal Cavities in the Ultrastrong Coupling Regime
• Using Superconducting Qubit Circuits to Engineer Exotic Lattice Systems
• Four-qubit device with mixed couplings
• Fate of photon blockade in the deep strong coupling regime
• Multi-output microwave single-photon source using superconducting circuits with longitudinal and transverse couplings
• Spectroscopy of three strongly coupled flux qubits
• Simultaneously exciting two atoms with photon-mediated Raman interaction

Cited by in corpus (12)

• Nonadiabatic Landau-Zener-Stückelberg-Majorana transitions, dynamics, and interference
• Quantum amplification and simulation of strong and ultrastrong coupling of light and matter
• Fast binomial-code holonomic quantum computation with ultrastrong light-matter coupling
• Simulating Anisotropic quantum Rabi model via frequency modulation
• Enhanced-Fidelity Ultrafast Geometric Quantum Computation Using Strong Classical Drives
• Coherent Resonant Coupling between Atoms and a Mechanical Oscillator Mediated by Cavity-Vacuum Fluctuations
• Multi-qubit Quantum Rabi Model and Multi-partite Entangled States in a Circuit QED System
• Vibration-Assisted Multi-Photon Resonance and Multi-Ion Excitation
• Current biased gradiometric flux qubit in a circuit-QED architecture
• Nonequilibrium thermal transport and photon squeezing in a quadratic qubit-resonator system
• On-chip Frequency divider in superconducting quantum circuit
• Two-Polariton Blockade via Ultrastrong Light-Matter Coupling