Quantum emulation of the transient dynamics in the multistate Landau-Zener model

TL;DR

This paper demonstrates quantum simulation of the multistate Landau-Zener model using superconducting circuits, exploring how initial states and coupling strength influence transient dynamics, with implications for complex quantum system emulation.

Contribution

It presents an experimental emulation of the multistate Landau-Zener model with superconducting circuits, including tunable qubit-resonator interactions and diverse initial states, advancing quantum simulation capabilities.

Findings

Transient dynamics depend on initial photon number.

Higher effective coupling leads to quasi-adiabatic transitions.

Coherent oscillations are suppressed at strong coupling.

Abstract

Quantum simulation is one of the most promising near term applications of quantum computing. Especially, systems with a large Hilbert space are hard to solve for classical computers and thus ideal targets for a simulation with quantum hardware. In this work, we study experimentally the transient dynamics in the multistate Landau-Zener model as a function of the Landau-Zener velocity. The underlying Hamiltonian is emulated by superconducting quantum circuit, where a tunable transmon qubit is coupled to a bosonic mode ensemble comprising four lumped element microwave resonators. We investigate the model for different initial states: Due to our circuit design, we are not limited to merely exciting the qubit, but can also pump the harmonic modes via a dedicated drive line. Here, the nature of the transient dynamics depends on the average photon number in the excited resonator. The greater effective coupling strength between qubit and higher Fock states results in a quasi-adiabatic transition, where coherent quantum oscillations are suppressed without the introduction of additional loss channels. Our experiments pave the way for more complex simulations with qubits coupled to an engineered bosonic mode spectrum.