Browsing by Author "Cosco, Francesco"
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- Bose-Hubbard lattice as a controllable environment for open quantum systems
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-04-09) Cosco, Francesco; Borrelli, Massimo; Mendoza-Arenas, Juan José; Plastina, Francesco; Jaksch, Dieter; Maniscalco, SabrinaWe investigate the open dynamics of an atomic impurity embedded in a one-dimensional Bose-Hubbard lattice. We derive the reduced evolution equation for the impurity and show that the Bose-Hubbard lattice behaves as a tunable engineered environment allowing one to simulate both Markovian and non-Markovian dynamics in a controlled and experimentally realizable way. We demonstrate that the presence or absence of memory effects is a signature of the nature of the excitations induced by the impurity, being delocalized or localized in the two limiting cases of a superfluid and Mott insulator, respectively. Furthermore, our findings show how the excitations supported in the two phases can be characterized as information carriers. - Entanglement protection via periodic environment resetting in continuous-time quantum-dynamical processes
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-10-02) Bullock, Thomas; Cosco, Francesco; Haddara, Marwan; Raja, Sina Hamedani; Kerppo, Oskari; Leppäjärvi, Leevi; Siltanen, Olli; Talarico, N. Walter; De Pasquale, Antonella; Giovannetti, Vittorio; Maniscalco, SabrinaThe temporal evolution of entanglement between a noisy system and an ancillary system is analyzed in the context of continuous-time open quantum system dynamics. Focusing on a couple of analytically solvable models for qubit systems, we study how Markovian and non-Markovian characteristics influence the problem, discussing in particular their associated entanglement-breaking regimes. These performances are compared with those one could achieve when the environment of the system is forced to return to its input configuration via periodic instantaneous resetting procedures. - Memory effects in a quasiperiodic Fermi lattice
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-11-05) Cosco, Francesco; Maniscalco, SabrinaWe investigate a system of fermions trapped in a quasiperiodic potential from an open quantum system theory perspective, designing a protocol in which an impurity atom (a two-level system) is coupled to a trapped fermionic cloud described by the noninteracting Aubry-André model. The Fermi system is prepared in a charge-density-wave state before it starts its relaxation. In this work we focus our attention on the time evolution of the impurity in such an out-of-equilibrium environment and study whether the induced dynamics can be classified as Markovian or non-Markovian. We find how the localized phase of the Aubry-André model displays evidence of strong and stable memory effects and can be considered as a controllable and robust non-Markovian environment. - Momentum-resolved and correlation spectroscopy using quantum probes
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2017-05-19) Cosco, Francesco; Borrelli, Massimo; Plastina, Francesco; Maniscalco, SabrinaWe address some key conditions under which many-body lattice models, intended mainly as simulated condensed-matter systems, can be investigated via immersed, fully controllable quantum objects, namely quantum probes. First, we present a protocol that, for a certain class of many-body systems, allows for full momentum-resolved spectroscopy using one single probe. Furthermore, we demonstrate how one can extract the two-point correlations using two entangled probes. We apply our theoretical proposal to two well-known exactly solvable lattice models, a one-dimensional (1D) Kitaev chain and 2D superfluid Bose-Hubbard model, and show its accuracy as well as its robustness against external noise. - Nonequilibrium quantum thermodynamics in Coulomb crystals
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2017-06-20) Cosco, Francesco; Borrelli, M.; Silvi, Pietro; Maniscalco, S.; De Chiara, G.We present an in-depth study of the nonequilibrium statistics of the irreversible work produced during sudden quenches in proximity to the structural linear-zigzag transition of ion Coulomb crystals in 1+1 dimensions. By employing both an analytical approach based on a harmonic expansion and numerical simulations, we show the divergence of the average irreversible work in proximity to the transition. We show that the nonanalytic behavior of the work fluctuations can be characterized in terms of the critical exponents of the quantum Ising chain. Due to the technological advancements in trapped-ion experiments, our results can be readily verified. - Reservoir engineering using quantum optimal control for qubit reset
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-09-24) Basilewitsch, Daniel; Cosco, Francesco; Lo Gullo, Nicolino; Mottonen, Mikko; Ala-Nissila, Tapio; Koch, Christiane P.; Maniscalco, SabrinaWe determine how to optimally reset a superconducting qubit which interacts with a thermal environment in such a way that the coupling strength is tunable. Describing the system in terms of a time-local master equation with time-dependent decay rates and using quantum optimal control theory, we identify temporal shapes of tunable level splittings which maximize the efficiency of the reset protocol in terms of duration and error. Time-dependent level splittings imply a modification of the system-environment coupling, varying the decay rates as well as the Lindblad operators. Our approach thus demonstrates efficient reservoir engineering employing quantum optimal control. We find the optimized reset strategy to consist in maximizing the decay rate from one state and driving non-adiabatic population transfer into this strongly decaying state.