Quantum Logic Dequantization: Information Loss

An attempt to ascertain reasons of the quantum logic efficiency was made. To do this, we reduce the complete set of elementary quantum logic operations to the classical one via taking the semi-classical limit (dequantization). We estimate the amount of information loss for any element of the set and obtain general expression for the loss estimation of any quantum algorithm under dequantization. We demonstrate the technique on quantum discrete fast Fourier transform and Grover search algorithms.