Showing papers by "Alejandro Romanelli published in 2007"
TL;DR: In this article, the authors studied the quantum walk subjected to measurements with a Levy waiting-time distribution and found that the system has a sub-ballistic behavior instead of a diffusive one.
Abstract: We study the quantum walk subjected to measurements with a Levy waiting-time distribution. We find that the system has a sub-ballistic behavior instead of a diffusive one. We obtain an analytical expression for the exponent of the power law of the variance as a function of the characteristic parameter of the Levy distribution.
20 citations
TL;DR: It is found that both quantum walk and the quantum kicked rotor in resonance subjected to noise with a Lévy waiting time distribution have a sub-ballistic wave function spreading as shown by a power-law tail of the standard deviation.
Abstract: We investigate the quantum walk and the quantum kicked rotor in resonance subjected to noise with a Levy waiting time distribution. We find that both systems have a sub-ballistic wave function spreading as shown by a power-law tail of the standard deviation.
18 citations
TL;DR: In this article, the authors studied the resonances of the quantum kicked rotor subjected to an excitation that follows an aperiodic Fibonacci prescription, and they showed that the secondary resonances show a sub-ballistic behavior like the quantum walk with the same a periodic prescription for the coin.
7 citations
TL;DR: In this paper, the players perform measurements on a quantum system associated to a continuous time search algorithm and the measurements collapse the wave function into one of the two possible states, and the selection of a particular strategy is determined by the moments when the players measure.
Abstract: We build new quantum games, similar to the spin flip game, where as a novelty the players perform measurements on a quantum system associated to a continuous time search algorithm. The measurements collapse the wave function into one of the two possible states. These games are characterized by a continuous space of strategies and the selection of a particular strategy is determined by the moments when the players measure.
5 citations
TL;DR: In this paper, the authors analyze the responses of a quantum search algorithm to an external monochromatic field and to the decoherences introduced through measurement processes, and show that the effect of repeated measurements can be treated analytically and does not lead to drastic changes in the efficiency of the search algorithm.
Abstract: We analyze the responses of a quantum search algorithm to an external monochromatic field and to the decoherences introduced through measurement processes. The external field in general affects the functioning of the search algorithm. However, depending on the values of the field parameters, there are zones where the algorithm continues to work with good efficiency. The effect of repeated measurements can be treated analytically and, in general, does not lead to drastic changes in the efficiency of the search algorithm.
3 citations
TL;DR: This work uses the wave equation to obtain a classical analogue of the quantum search algorithm and verifies that the essence of search algorithms resides in the establishment of resonances between the initial and the searched states.
Abstract: In this work we use the wave equation to obtain a classical analogue of the quantum search algorithm and we verify that the essence of search algorithms resides in the establishment of resonances between the initial and the searched states. In particular we show that, within a set of N vibration modes, it is possible to excite the searched mode in a number of steps proportional to N .
1 citations