It’s a well-known fact that quantum calculations are difficult, but one would think that quantum computers would facilitate the process. In most cases, this is true.

Quantum bits, or qubits, use quantum phenomena, like superposition and entanglement, to process many possibilities simultaneously. This allows for exponentially faster computing for complex problems. However, Thomas Schuster, of California Institute of Technology, and his research team have given quantum computers a problem that even they can’t solve in a reasonable amount of time—recognizing phases of matter of unknown quantum states.

The team’s research can be found in a paper published on the arXiv preprint server.