The largest full quantum computer simulation done so far is 45-qubits which was performed on the Cori supercomputer [0][1]. The main limitation in these kinds

The largest full quantum computer simulation done so far is 45-qubits which was performed on the Cori supercomputer [0][1]. The main limitation in these kinds of exact simulations is memory, and so simulating 50-qubits would require about a 1000x the memory of Cori, which is infeasible. There are some other methods of approximate simulation, but that gives the cut off for full, exact simulation of a quantum computer. [0] https://www.nersc.gov/news-publications/nersc-news/science-news/2017-2/record-breaking-45-qubit-quantum-computing-simulation-run-at-nersc/ https://www.nersc.gov/news-publications/nersc-news/science-n... [1] https://arxiv.org/abs/1704.01127 https://arxiv.org/abs/1704.01127