0000000000460022

AUTHOR

Carlo Di Franco

showing 3 related works from this author

Competition between memory-keeping and memory-erasing decoherence channels

2014

We study the competing effects of simultaneous Markovian and non-Markovian decoherence mechanisms acting on a single spin. We show the existence of a threshold in the relative strength of such mechanisms above which the spin dynamics becomes fully Markovian, as revealed by the use of several non-Markovianity measures. We identify a measure-dependent nested structure of such thresholds, hinting at a causality relationship among the various non-Markovianity witnesses used in our analysis. Our considerations are then used to argue the unavoidably non-Markovian evolution of a single-electron quantum dot exposed to both intrinsic and Markovian technical noise, the latter of arbitrary strength. 

Quantum decoherenceNON-MARKOVIAN DYNAMICSMarkov processFOS: Physical sciencesRelative strengthSPINS01 natural sciencesNoise (electronics)Settore FIS/03 - Fisica Della Materia010305 fluids & plasmasCausality (physics)symbols.namesakeSYSTEMSQuantum mechanics0103 physical sciencesStatistical physicsQuantum information010306 general physicsSpin-½PhysicsQuantum Physics/dk/atira/pure/subjectarea/asjc/3100/3107Atomic and Molecular Physics and OpticsQuantum dotsymbolsSEMICONDUCTOR QUANTUM DOTSQuantum Physics (quant-ph)
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N-dimensional alternate coined quantum walks from a dispersion-relation perspective

2013

We propose an alternative definition of an N-dimensional coined quantum walk by generalizing a recent proposal [Di Franco et al., Phys. Rev. Lett. 106, 080502 (2011)]. This N-dimensional alternate quantum walk, AQW_N, in contrast with the standard definition of the N-dimensional quantum walk, QW_N, requires only a coin-qubit. We discuss the quantum diffusion properties of AQW_2 and AQW_3 by analyzing their dispersion relations that reveal, in particular, the existence of diabolical points. This allows us to highlight interesting similarities with other well known physical phenomena. We also demonstrate that AQW_3 generates genuine multipartite entanglement. Finally we discuss the implementa…

PhysicsQuantum PhysicsN dimensionalFOS: Physical sciencesQuantum diffusion01 natural sciencesMultipartite entanglementAtomic and Molecular Physics and OpticsÒptica quàntica010305 fluids & plasmasPerspective (geometry)Standard definitionQubitQuantum mechanicsDispersion relation0103 physical sciencesQuantum walkQuantum Physics (quant-ph)010306 general physicsPhysical Review A
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Chirality asymptotic behavior and non-Markovianity in quantum walks on a line

2014

We investigate the time evolution of the chirality reduced density matrix for a discrete-time quantum walk on a one-dimensional lattice, which is obtained by tracing out the spatial degree of freedom. We analyze the standard case, without decoherence, and the situation where decoherence appears in the form of broken links in the lattice. By examining the trace distance for possible pairs of initial states as a function of time, we conclude that the evolution of the reduced density matrix is non-Markovian, in the sense defined in [H. P. Breuer, E. M. Laine, and J. Piilo, Phys. Rev. Lett. 103, 210401 (2009)]. As the level of noise increases, the dynamics approaches a Markovian process. The hi…

PhysicsQuantum PhysicsQuantum decoherenceTime evolutionFísicaFOS: Physical sciencesMarkov processAtomic and Molecular Physics and Opticssymbols.namesakeLattice (order)Quantum mechanicsTrace distancesymbolsQuantum walkReduced density matrixQuantum Physics (quant-ph)Physical Review A
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