Signal enhancement and background suppression using interference and entanglement

Keith Kastella, Ralph S. Conti
2011 Physical Review A. Atomic, Molecular, and Optical Physics  
In the multitarget Grover algorithm, we are given an unstructured N-element list of objects S_i containing a T-element subset tau and function f, called an oracle, such that f(S_i)=1 if S_i is in tau, otherwise f(S_i) = 0. By using quantum parallelism, an element of tau can be retrieved in O(sqrt(N/T)) steps, compared to O(N/T) for any classical algorithm. It is shown here that in combinatorial optimization problems with N=4^M, the density of states can be used in conjunction with the
more » ... t Grover algorithm to construct a sequence of oracles that structure the search so that the optimum state is obtained with certainty in O(log(N)) steps.
doi:10.1103/physreva.83.014302 fatcat:7yyoxo4ofza73fb3uazuglhcfm