  Quantum computational devices, currently under development, have the
potential to accelerate data analysis techniques beyond the ability of any
classical algorithm. We propose the application of a quantum algorithm for the
detection of unknown signals in noisy data. We apply Grover's algorithm to
matched-filtering, a signal processing technique that compares data to a number
of candidate signal templates. In comparison to the classical method, this
provides a speed-up proportional to the square-root of the number of templates,
which would make possible otherwise intractable searches. We demonstrate both a
proof-of-principle quantum circuit implementation, and a simulation of the
algorithm's application to the detection of the first gravitational wave signal
GW150914. We discuss the time complexity and space requirements of our
algorithm as well as its implications for the currently computationally-limited
searches for continuous gravitational waves.
