Approximate Quantum Fourier Transform and Decoherence
  We discuss the advantages of using the approximate quantum Fourier transform (AQFT) in algorithms which involve periodicity estimations. We analyse quantum networks performing AQFT in the presence of decoherence and show that extensive approximations can be made before the accuracy of AQFT (as compared with regular quantum Fourier transform) is compromised. We show that for some computations an approximation may imply a better performance. 
Adriano Barenco (1), Artur Ekert (1), Kalle-Antti Suominen (2) and   P\"aivi T\"orm\"a (3) ((1) Clarendon Laboratory, Depart...