  A proof-of-concept application of a quantum algorithm to multiloop Feynman
integrals in the Loop-Tree Duality (LTD) framework is applied to a
representative four-loop topology. Bootstrapping causality in the LTD
formalism, is a suitable problem to address with quantum computers given the
straightforward possibility to encode the two on-shell states of a propagator
on the two states of a qubit. A modification of Grover's quantum search
algorithm is developed and the quantum algorithm is successfully implemented on
IBM Quantum and QUTE simulators.
