Classical analog of quantum search
Lov K. Grover, Anirvan M. Sengupta · Physical Review A · 2002
Quantum search is a quantum-mechanical technique for searching N possibilities in only $\sqrt{N}$ steps. A similar algorithm applies in a purely classical setting when there are N oscillators, one of which is of a different resonant frequency. We could identify which one this is by measuring the oscillation frequency of each oscillator, a procedure that would take about N cycles. We show, how by coupling the oscillators together in a very simple way, it is possible to identify the different one in only $\sqrt{N}$ cycles. In case there are multiple oscillators of a different frequency, we can estimate the number of these in a time which is the square root of that required by the sampling method. The analog also leads to some energy routing algorithms for mechanical systems.