Towards Quantum Simulation of Bound States Scattering

The last years have seen a rapid development of applications of quantum computationto quantum field theory. The first quantum algorithms for simulation of scattering havebeen proposed in the context of scalar and fermionic theories, requiring thousands oflogical qubits.

These algorithms are not suitable to simulate scattering of incomingbound states, as the initial state preparation relies typically on adiabaticallytransforming wavepackets of the free theory into wavepackets of the interactingtheory.In this talk, I will present a strategy to excite wavepackets of the interactingtheory directly from the vacuum of the interacting theory, allowing for preparation ofstates of composite particles that can be taken as initial states of a scatteringsimulation.

This is the first step towards digital quantum simulation of scattering ofbound states. The approach is based on the Haag-Ruelle scattering theory, whichprovides a way to construct creation and annihilation operators of a quantum fieldtheory in a full, nonperturbative framework. To show that the idea works for quantumcomputation, I will describe a quantum algorithm implementing the approach.