%0 Journal Article %T Quantum-Classical Algorithm for an Instantaneous Spectral Analysis of Signals: A Complement to Fourier Theory %A Mario Mastriani %J Journal of Quantum Information Science %P 52-77 %@ 2162-576X %D 2018 %I Scientific Research Publishing %R 10.4236/jqis.2018.82005 %X A quantum time-dependent spectrum analysis, or simply, quantum spectral analysis (QSA) is presented in this work, and itĄ¯s based on SchrödingerĄ¯s equation. In the classical world, it is named frequency in time (FIT), which is used here as a complement of the traditional frequency-dependent spectral analysis based on Fourier theory. Besides, FIT is a metric which assesses the impact of the flanks of a signal on its frequency spectrum, not taken into account by Fourier theory and lets alone in real time. Even more, and unlike all derived tools from Fourier Theory (i.e., continuous, discrete, fast, short-time, fractional and quantum Fourier Transform, as well as, Gabor) FIT has the following advantages, among others: 1) compact %K Fourier Theory %K HeisenbergĄ¯s Uncertainty Principle %K Quantum Fourier Transform %K Quantum Information Processing %K Quantum Signal Processing %K Schrö %K dingerĄ¯s Equation %K Spectral Analysis %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=85232