S. Maniscalco

University of Turku, Turku, Province of Western Finland, Finland

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Publications (103)217.89 Total impact

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    ABSTRACT: We address the dynamics of nonclassicality for a quantum system interacting with a noisy fluctuating environment described by a classical stochastic field. As a paradigmatic example, we consider a harmonic oscillator initially prepared in a maximally nonclassical state, e.g. a Fock number state or a Schroedinger cat-like state, and then coupled to either resonant or non-resonant external field. Stochastic modeling allows us to describe the decoherence dynamics without resorting to approximated quantum master equations, and to introduce non- Markovian effects in a controlled way. A detailed comparison among different nonclassicality criteria and a thorough analysis of the decoherence time reveal a rich phenomenology whose main features may be summarized as follows: i) classical memory effects increase the survival time of quantum coherence; ii) a detuning between the natural frequency of the system and the central frequency of the classical field induces revivals of quantum coherence.
    11/2014;
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    ABSTRACT: We theoretically investigate fluctuation relations in a classical incomplete measurement process where just partial information is available. The scenario we consider consists of two coupled single-electron boxes where one or both devices can undergo a non-equilibrium transformation according to a chosen protocol. The entropy production of only one of the two boxes is recorded and fluctuation relations for this quantity are put to a test, showing strong modifications whose nature depends upon the specific case study.
    10/2014;
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    B Bylicka, D Chruściński, S Maniscalco
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    ABSTRACT: Quantum technologies rely on the ability to coherently transfer information encoded in quantum states along quantum channels. Decoherence induced by the environment sets limits on the efficiency of any quantum-enhanced protocol. Generally, the longer a quantum channel is the worse its capacity is. We show that for non-Markovian quantum channels this is not always true: surprisingly the capacity of a longer channel can be greater than of a shorter one. We introduce a general theoretical framework linking non-Markovianity to the capacities of quantum channels and demonstrate how harnessing non-Markovianity may improve the efficiency of quantum information processing and communication.
    Scientific Reports 07/2014; 4:5720. · 5.08 Impact Factor
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    ABSTRACT: We extend the definition of entanglement witnesses based on structure factors to the case in which the position of the scatterers is quantized. This allows us to study entanglement detection in hybrid systems. We provide several examples that show how these extra degrees of freedom affect the detection of entanglement by directly contributing to the measurement statistics. We specialize the proposed witness operators for a chain of trapped ions. Within this framework, we show how the collective vibronic state of the chain can act as an undesired quantum environment and how ions quantum motion can affect the entanglement detection. Finally, we investigate some specific cases where the method proposed leads to detection of hybrid entanglement.
    Physical Review A 04/2014; 90(2). · 3.04 Impact Factor
  • Massimo Borrelli, Sabrina Maniscalco
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    ABSTRACT: In this paper we generalize the results reported in Phys. Rev. A 88, 010101 (2013) and investigate the flow of information induced in a Coulomb crystal in presence of thermal noise. For several temperatures we calculate the non-Markovian character of Ramsey interferometry of a single 1/2 spin with the motional degrees of freedom of the whole chain. These results give a more realistic picture of the interplay between temperature, non-Markovianity and criticality.
    International Journal of Quantum Information 04/2014; 12(02). · 0.92 Impact Factor
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    Dariusz Chruściński, Sabrina Maniscalco
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    ABSTRACT: We propose a new characterization of non-Markovian quantum evolution based on the concept of non-Markovianity degree. It provides an analog of a Schmidt number in the entanglement theory and reveals the formal analogy between quantum evolution and the entanglement theory: Markovian evolution corresponds to a separable state and the non-Markovian one is further characterized by its degree. It enables one to introduce a non-Markovianity witness-an analog of an entanglement witness, and a family of measures-an analog of Schmidt coefficients, and finally to characterize maximally non-Markovian evolution being an analog of the maximally entangled state. Our approach allows us to classify the non-Markovianity measures introduced so far in a unified rigorous mathematical framework.
    Physical Review Letters 03/2014; 112(12):120404. · 7.73 Impact Factor
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    Pinja Haikka, Sabrina Maniscalco
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    ABSTRACT: We review the most recent developments in the theory of open quantum systems focusing on situations in which the reservoir memory effects, due to long-lasting and non-negligible correlations between system and environment, play a crucial role. These systems are often referred to as non-Markovian systems. After a brief summary of different measures of non-Markovianity that have been introduced over the last few years we restrict our analysis to the investigation of information flow between system and environment. Within this framework we introduce an important application of non-Markovianity, namely its use as a quantum probe of complex quantum systems. To illustrate this point we consider quantum probes of ultracold gases, spin chains, and trapped ion crystals and show how properties of these systems can be extracted by means of non-Markovianity measures.
    Open Systems & Information Dynamics 03/2014; 21(01n02). · 0.90 Impact Factor
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    ABSTRACT: In this paper we present a detailed critical study of several recently proposed non-Markovianity measures. We analyse their properties for single qubit and two-qubit systems in both pure-dephasing and dissipative scenarios. More specifically we investigate and compare their computability, their physical meaning, their Markovian to non-Markovian crossover, and their additivity properties with respect to the number of qubits. The bottom-up approach that we pursue is aimed at identifying similarities and differences in the behavior of non-Markovianity indicators in several paradigmatic open system models. This in turn allows us to infer the leading traits of the variegated phenomenon known as non-Markovian dynamics and, possibly, to grasp its physical essence.
    02/2014;
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    ABSTRACT: We study the interplay between coherence trapping, information back-flow and the form of the reservoir spectral density for dephasing qubits. We show that stationary coherence is maximized when the qubit undergoes non-Markovian dynamics, and we elucidate the different roles played by the low and high frequency parts of the environmental spectrum. We show that the low frequencies fully determine the presence or absence of information back-flow while the high frequencies dictate the maximal amount of coherence trapping.
    11/2013; 89(2).
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    ABSTRACT: In this article, we discuss the development and evaluation of a game designed to harness non-expert human intuition for scientific research in the field of Quantum Physics (Quantum Information). Since many physics problems are represented and analysed in a geometric space, we hypothesized that human predispositions such as geo-spatial intuition could be considered as a means to reduce the search space in some optimisation problems in quantum information which are currently solved through brute force approaches. We developed a 3D digital game in order to investigate players’ ability to solve a known and quantifiable current research problem in quantum physics. In this article, we describe our motivations for conducting this work, the game design and its implementation, our experimental design and an analysis of the results obtained via player evaluation. Initial results are promising, indicating that players can indeed find known solutions to the example problem.
    Serious Games Development and Applications: 4th International Conference, SGDA 2013, Trondheim, Norway; 09/2013
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    C. Benedetti, M. G. A. Paris, S. Maniscalco
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    ABSTRACT: We address the non-Markovian character of noisy maps describing the interaction of a qubit with a random classical field. In particular, we evaluate trace- and capacity-based non-Markovianity measures for two relevant classes of environments showing non-Gaussian fluctuations, described respectively by random telegraph noise (RTN) and colored noise with spectra of the the form 1/f^\alpha. We analyze the dynamics of both the trace distance and the quantum or entanglement assisted capacity, and show that the behaviour of non-Markovianity based on both measures is qualitatively similar. Our results show that environments with a spectrum that contains a relevant low-frequency contribution are generally non-Markovian. We also find that non-Markovianity of colored environments decreases when the number of fluctuators realizing the envinroment increases. Finally, we discuss how reliable transmission of information through a quantum channel subjected to random classical noise may be achieved by tailoring the channel length and properly engineering the structured environments.
    09/2013; 89(1).
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    ABSTRACT: We study the entanglement of two impurity qubits immersed in a Bose-Einstein condensate (BEC) reservoir. This open quantum system is particularly interesting because the reservoir and system parameters are easily controllable and the reduced dynamics is highly non-Markovian. We show how the model allows for interpolation between a common dephasing scenario and an independent dephasing scenario by simply modifying the wavelength of the superlattice superposed to the BEC, and how this influences the dynamical properties of the impurities. We demonstrate the existence of very rich entanglement dynamics correspondent to different values of reservoir parameters, including phenomena such as entanglement trapping, entanglement sudden death, revivals of entanglement, and BEC-mediated entanglement generation. In the spirit of reservoir engineering, we present the optimal BEC parameters for entanglement generation and trapping, showing the key role of the ultracold gas interactions.
    EPL (Europhysics Letters) 04/2013; 101:60005. · 2.26 Impact Factor
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    ABSTRACT: We investigate the back-flow of information in a system with a second-order structural phase transition, namely a quasi one-dimensional Coulomb crystal. Using standard Ramsey interferometry which couples a target ion (the system) to the rest of the chain (a phononic environment), we study the non-Markovian character of the resulting open system dynamics. We study two different time-scales and show that the back-flow of information pinpoints both the phase transition and different dynamical features of the chain as it approaches criticality. We also establish an exact link between the back-flow of information and the Ramsey fringe visibility.
    Physical Review A 02/2013; 88(1). · 3.04 Impact Factor
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    ABSTRACT: We study non-Markovianity as backflow of information in two-qubit systems. We consider a setting where, by changing the distance between the qubits, one can interpolate between independent reservoir and common reservoir scenarios. We demonstrate that non-Markovianity can be induced by the common reservoir and single out the physical origin of this phenomenon. We show that two-qubit non-Markovianity coincides with instances of non-divisibility of the corresponding dynamical map, and we discuss the pair of states maximizing information flowback. We also discuss the issue of additivity for the measure we use and in doing so, give an indication of its usefulness as a resource for multipartite quantum systems.
    Physical Review A 02/2013; 87(5). · 3.04 Impact Factor
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    Bogna Bylicka, Dariusz Chruściński, Sabrina Maniscalco
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    ABSTRACT: Quantum technologies rely on the ability to coherently manipulate, process and transfer information, encoded in quantum states, along quantum channels. Decoherence induced by the environment introduces errors, thus setting limits on the efficiency of any quantum-enhanced protocol or device. A fundamental bound on the ability of a noisy quantum channel to transmit quantum (classical) information is given by its quantum (classical) capacity. Generally, the longer is a quantum channel the more are the introduced errors, and hence the worse is its capacity. In this Letter we show that for non-Markovian quantum channels this is not always true: surprisingly the capacity of a longer channel can be greater than the one of a shorter channel. We introduce a general theoretical framework linking non-Markovianity to the capacities of quantum channels, and demonstrate in full generality how harnessing non-Markovianity may improve the efficiency of quantum information processing and communication.
    01/2013;
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    Pinja Haikka, Suzanne McEndoo, Sabrina Maniscalco
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    ABSTRACT: We present a detailed investigation of the dynamics of two physically different qubit models, dephasing under the effect of an ultracold atomic gas in a Bose-Einstein condensed (BEC) state. We study the robustness of each qubit probe against environmental noise; even though the two models appear very similar at a first glance, we demonstrate that they decohere in a strikingly different way. This result holds significance for studies of reservoir engineering as well as for using the qubits as quantum probes of the ultracold gas. For each model we study whether and when, upon suitable manipulation of the BEC, the dynamics of the qubit can be described by a (non-)Markovian process and consider the the effect of thermal fluctuations on the qubit dynamics. Finally, we provide an intuitive explanation for the phenomena we observe in terms of the spectral density function of the environment.
    Physical Review A 01/2013; 87(1). · 3.04 Impact Factor
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    ABSTRACT: Knowledge of the dynamical behavior of correlations with no classical counterpart, like entanglement, nonlocal correlations and quantum discord, in open quantum systems is of primary interest because of the possibility to exploit these correlations for quantum information tasks. Here we review some of the most recent results on the dynamics of correlations in bipartite systems embedded in non-Markovian environments that, with their memory effects, influence in a relevant way the system dynamics and appear to be more fundamental than the Markovian ones for practical purposes. Firstly, we review the phenomenon of entanglement revivals in a two-qubit system for both independent environments and a common environment. We then consider the dynamics of quan-tum discord in non-Markovian dephasing channel and briefly discuss the occurrence of revivals of quantum correlations in classical environments.
    International Journal of Modern Physics B 01/2013; 27:1245053. · 0.46 Impact Factor
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    ABSTRACT: We address the dynamics of quantum correlations in continuous variable open systems and analyze the evolution of bipartite Gaussian states in independent noisy channels. In particular, upon introducing the notion of dynamical path through a suitable parametrization for symmetric states, we focus attention on phenomena that are common to Markovian and non-Markovian Gaussian maps under the assumptions of weak coupling and secular approximation. We found that the dynamical paths in the parameter space are universal, that is they do depend only on the initial state and on the effective temperature of the environment, with non Markovianity that manifests itself in the velocity of running over a given path. This phenomenon allows one to map non-Markovian processes onto Markovian ones and it may reduce the number of parameters needed to study a dynamical process, e.g. it may be exploited to build constants of motions valid for both Markovian and non-Markovian maps. Universality is also observed in the value of Gaussian discord at the separability threshold, which itself is a function of the sole initial conditions in the limit of high temperature. We also prove the existence of excluded regions in the parameter space, i.e. of sets of states which cannot be linked by any Gaussian dynamical map.
    Physical Review A 11/2012; · 3.04 Impact Factor
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    ABSTRACT: Simulation methods based on stochastic realizations of state vector evolutions are commonly used tools to solve open quantum system dynamics, both in the Markovian and non-Markovian regimes. Here, we address the question of the waiting time distribution (WTD) of quantum jumps for non-Markovian systems. We generalize Markovian quantum trajectory methods in the sense of deriving an exact analytical WTD for non-Markovian quantum dynamics and show explicitly how to construct this distribution for certain commonly used quantum optical systems.
    Physical Review A 07/2012; 86(2). · 3.04 Impact Factor
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    ABSTRACT: We study a single two-level atom interacting with a reservoir of modes defined by a reservoir structure function with a frequency gap. Using the pseudomodes technique, we derive the main features of a trapping state formed in the weak coupling regime. Utilizing different entanglement measures we show that strong correlations and entanglement between the atom and the modes are in existence when this state is formed. Furthermore, an unexpected feature for the reservoir is revealed. In the long time limit and for weak coupling the reservoir spectrum is not constant in time.
    Physical Review A 07/2012; 86(1). · 3.04 Impact Factor

Publication Stats

1k Citations
217.89 Total Impact Points

Institutions

  • 2006–2014
    • University of Turku
      • • Department of Physics and Astronomy
      • • Department of Physiatrics
      Turku, Province of Western Finland, Finland
  • 2010–2013
    • Heriot-Watt University
      • School of Engineering and Physical Sciences
      Edinburgh, Scotland, United Kingdom
  • 2012
    • Università della Calabria
      • Department of Physics
      Rende, Calabria, Italy
  • 2000–2008
    • Università degli studi di Palermo
      • Dipartimento di Fisica e Chimica
      Palermo, Sicily, Italy
  • 2004
    • University of KwaZulu-Natal
      • Department of Physics
      Port Natal, KwaZulu-Natal, South Africa