Quantum Computation is a relatively new research area, which has been in development in the past 20 years, and which makes use of the fundamentals of Computer Science and Quantum Physics. Two are the quantum phenomena in which Quantum Computation is based: superposition and interference. In this work, we will highlight the role of interference in the solution of the problem proposed by Deutsch, which consists of knowing if a given function is constant or balanced, executing the function only once. Figuratively, this is the same as knowing if a coin is honest or faked (two equal faces) looking only once. Deutsch's solution (algorithm) is frequently explained in an abstract manner and with the help of circuits. However, although efficient to express the "logics" and facilitate the development of quantum algorithms, that approach does not make it clear and easy to realize the underlying physical phenomena. In this work, we show, in a didatic way, how the Mach-Zehnder interferometer implements Deutsch's algorithm, thus highlighting the importance of interference in the realization of quantum algorithms.
Deutsch algorithm; Mach-Zehnder interferometer; quantum computation
