Fast Simulation of Bosonic Qubits via Gaussian Functions in Phase Space

Bosonic qubits are a promising route to building fault-tolerant quantum computers on variety of physical platforms. Studying the performance bosonic under realistic gates and measurements is challenging with existing analytical numerical tools. We present novel formalism for simulating classes states that can be represented as linear combinations Gaussian functions in phase space. This allows us analyze simulate wide class non-Gaussian states, transformations measurements. demonstrate how useful -- Gottesman-Kitaev-Preskill (GKP), cat, Fock simulated using this formalism, opening door investigating behaviour channels measurements, such those achieved via gate teleportation, important threshold photon-number detection. Our enables these situations levels accuracy not feasible methods. Finally, we use method informed by our circuits critical study computing but beyond reach techniques. Specifically, examine finite-energy GKP transform qubit gates; interface CV cluster state; non-Clifford T teleportation magic states. implement simulation part open-source Strawberry Fields Python library.