Quantum simulation of real-time Yukawa dynamics with qubits and qumodes

Abstract

Real-time quantum simulation of field theories offers access to scattering and decay dynamics, circumventing the limitations of Euclidean lattice methods. However, representing bosonic fields on qubits requires a finite-dimensional approximation and can entail costly multi-qubit operations. Hybrid qubit-qumode architectures avoid this by encoding bosonic fields directly in oscillators. We formulate scattering in the (1+1)-dimensional Yukawa theory for such a device, with staggered fermions on qubits and the scalar on qumodes. Trapped ions are a natural candidate, with the fermions on the internal states of the ions and the scalar on their collective motion, so that the Yukawa coupling becomes a native spin-dependent displacement. Emulating the device with tensor networks, we study the decay of a single scalar particle and fermion-antifermion scattering around the resonance region, using observables that can be measured on the device natively. We compare the results with those obtained using lattice perturbation theory. The emulation is able to resolve corrections beyond the Dyson summation of the one-loop self-energy.