QTensor: Parallel Quantum Circuit Simulator

We present a parallel quantum circuit simulator* designed to run on large supercomputers with the eventual goal to run at scale on exa-scale supercomputers Aurora and Frontier. The simulator is based on the tensor network representation of quantum circuits. We proposed a novel parallelization strategy that is based on the splitting of the partially contracted tensor expression. The resulting slices of the tensor expression had significantly smaller memory footprints which allowed us to contract partial tensor networks on individual MPI ranks. We will discuss the performance considerations of working with tensor networks at scale and demonstrate the efficiency of QAOA simulation in a hybrid GPU-CPU environment using both Xeon Phi and Nvidia GPUs, on circuits with over a large number of qubits.

*QTensor code is publicity available at https://github.com/danlkv/QTensor