Simulating a Quasiparticle on a Quantum Device

Quantum simulation of many-body systems is one of the most promising applications for near-term noisy intermediate-scale quantum devices. In this work, we propose a variational approach to explore quasiparticle excitations in interacting quantum systems using quantum devices.

By exploiting translation invariance and abelian symmetries of the many-body Hamiltonian, we extend the Variational Quantum Eigensolver (VQE) to construct spatially localized quasiparticle states that encode information about the entire excited band, allowing us to achieve quantum parallelism.

We benchmark our algorithm on the transverse field Ising chain, successfully simulating both magnon quasiparticles in the paramagnetic phase and topologically non-trivial soliton quasiparticles in the ferromagnetic phase. Our VQE simulations demonstrate that these quasiparticle states constructed with VQE contain accessible information on the full band of excitations, even when the quasiparticles are highly renormalized near criticality. We also detail how to extract experimentally measurable quantities such as the band gap and quasiparticle renormalization strength from these simulations.

These results offer valuable theoretical insights for utilizing quantum simulators to access the quasiparticles of strongly interacting quantum systems, opening new avenues for investigating strongly correlated quantum systems on quantum devices.