Speaker

Professor Joonsuk Huh, Yonsei University

Title

"Bosonic Boosts: Dual-Rail Encoding and Nonlinear Vibronic Simulation on Oscillator–Qubit Platforms"

Abstract

Oscillator–qubit hybrid architectures naturally provide bosonic modes that can enlarge quantum registers or reproduce many-body dynamics. I will discuss two recent approaches that utilize this flexibility practically. First [1], I will describe a scheme that treats the vibrational modes of trapped ions not as mere quantum buses but as computational resources in their own right. By encoding a dual-rail qubit in two phonon modes that share a single excitation, we realize universal gate operations—state preparation, measurement, and both single- and two-qubit gates—using only standard trapped-ion controls. Because every ion supplies two readily addressable vibrational modes, the architecture scales naturally and preserves all-to-all connectivity. Second [2], I will present a simulation of nonadiabatic molecular processes beyond linear vibronic models. Taking the uracil cation as an example, nonlinear chemical potentials and multiple electronic levels are embedded in an oscillator-qubit framework. Oscillator–qubit hybrid quantum signal processing provides the nonlinear bosonic phase gates necessary to construct the anharmonic Hamiltonian. Together, the results suggest that modest enhancements to current hardware can expand the scope of near-term quantum experiments.
[1] Kang et al., Doubling Qubits in a Trapped-Ion System via Vibrational Dual-Rail Encoding, arXiv:2505.12937
[2] Hong et al., Oscillator-qubit quantum signal processing for multilevel nonlinear vibronic models: a case study of uracil cation, in preparation