Cut Noise.
Work Quantum.

Analogy

To build a photonic quantum computer, you need all your photons to be perfectly identical 'twins.' Previous methods for checking this were like comparing every possible pair of twins in a crowd, which becomes impossible as the crowd grows. This new method uses a 'Quantum Fourier Transform' interferometer as a filter; if the photons are identical, they follow strict rules that prevent them from appearing at certain exits. By checking those 'suppressed' exits, we can verify the quality of the photons much faster than ever before.