Quantum Simulation of Quantum Z2 Gauge Theory demonstrated in a GPU Simulator*

We outline a quantum simulation scheme of quantum Z2 gauge theory using quantum adiabatic algorithm implemented in terms of quantum circuit, and then demonstrate it in the classical simulator QuEST using a CUDA enabled GPU server. In particular, we obtained useful results in (3+1)-dimensional and (2+1)-dimensional theories. It is identified that the quantum phase transition is topological in both dimensions, and is first-order in (3+1) dimensions but second-order in (2+1) dimensions. High-performance classical simulation of quantum simulation, which may be dubbed pseudoquantum simulation, is not only a platform of developing quantum software, but also represents a new practical mode of computation.