Sabrina Maniscalco

University of Turku, Turku, Varsinais-Suomi, Finland

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Publications (117)233.48 Total impact

  • Carole Addis · Göktuğ Karpat · Sabrina Maniscalco
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    ABSTRACT: Dynamical decoupling protocols are one of the most used tools for efficient quantum error corrections and for reservoir engineering. In this paper we study the effect of dynamical decoupling pulses on the preservation of both quantum and classical correlations, and their influence on the intriguing phenomenon of time-invariant discord. We study two qubits experiencing local dephasing with an Ohmic class spectrum and subject to dynamical decoupling protocols. We investigate the connection between the dynamics of both classical and quantum correlations and the behaviour of information flow between system and environment. Finally, we establish a set of necessary conditions for which time-invariant discord can be created using dynamically decoupling techniques.
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    ABSTRACT: The non-classical nature of quantum states, often illustrated using entanglement measures or quantum discord, constitutes a resource for quantum information protocols. However, the non-classicality of a quantum system cannot be encapsulated as a property of the state alone, as the set of available measurements used to extract information on the system is typically restricted. In this work we study how the non-classicality of quantum measurements, quantified via their incompatibility, is influenced by quantum noise and, further, how a non-Markovian environment may help us in maintaining the measurement resources.
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    ABSTRACT: Many quantum information tasks rely on entanglement, which is used as a resource, for example, to enable efficient and secure communication. Typically, noise, accompanied by loss of entanglement, reduces the efficiency of quantum protocols. We demonstrate experimentally a superdense coding scheme with noise, where the decrease of entanglement in Alice's encoding state does not reduce the efficiency of the information transmission. Having almost fully dephased classical two-photon polarization state at the time of encoding, we reach values of mutual information close to 1.52 (1.89) with 3-state (4-state) encoding. This high efficiency relies both on non-Markovian features, that Bob exploits just before his Bell-state measurement, and on very high visibility (99.6$\%$) of the Hong-Ou-Mandel interference within the experimental set-up. Our proof-of-principle results pave the way for exploiting non-Markovianity to improve the efficiency and security of quantum information processing tasks.
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    ABSTRACT: We establish a connection between non-Markovian memory effects and thermodynamical quantities such as work. We show how memory effects can be interpreted as revivals of work that can be extracted from a quantum system. We prove that non-Markovianity may allow an increase in the extractable work even when the entropy of the system is increasing. Our results have important implications both in quantum thermodynamics and in quantum information theory. In the former context they pave the way to the understanding of concepts like work in a non-Markovian open system scenario. In the latter context they lead to interesting consequences for quantum state merging protocols in presence of noise.
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    Göktuğ Karpat · Jyrki Piilo · Sabrina Maniscalco
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    ABSTRACT: One of the defining traits of quantum mechanics is the uncertainty principle which was originally expressed in terms of the standard deviation of two observables. Alternatively, it can be formulated using entropic measures, and can also be generalized by including a memory particle that is entangled with the particle to be measured. Here we consider a realistic scenario where the memory particle is an open system interacting with an external environment. Through the relation of conditional entropy to mutual information, we provide a link between memory effects and the rate of change of conditional entropy controlling the lower bound of the entropic uncertainty relation. Our treatment reveals that the memory effects stemming from the non-Markovian nature of quantum dynamical maps directly control the lower bound of the entropic uncertainty relation in a general way, independently of the specific type of interaction between the memory particle and its environment.
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    ABSTRACT: We consider structured environments modeled by bosonic quantum networks and investigate the control and probing of their spectral density. We demonstrate how to engineer a desired spectral density by changing the network structure. We show that the spectral density can be very accurately detected via a locally immersed probe system for virtually any network configuration. We illustrate our findings presenting examples of spectral densities for networks of genuine complexity.
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    ABSTRACT: We investigate the relationship between non-Markovianity and the effectiveness of a dynamical decoupling protocol for qubits undergoing pure dephasing. We consider an exact model in which dephasing arises due to a bosonic environment with a spectral density of the Ohmic class. This is parametrised by an Ohmicity parameter by changing which we can model both Markovian and non-Markovian environments. Interestingly, we find that engineering a non-Markovian environment is detrimental to the efficiency of the dynamical decoupling scheme, leading to a worse coherence preservation. We show that each dynamical decoupling pulse reverses the flow of quantum information and, on this basis, we investigate the connection between dynamical decoupling efficiency and the reservoir spectral density. Finally, in the spirit of reservoir engineering, we investigate the optimum system-reservoir parameters for achieving maximum stationary coherences.
  • Jacopo Trapani · Matteo Bina · Sabrina Maniscalco · Matteo G. A. Paris
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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 Schr\"odinger-cat-like state, and then coupled to either a resonant or a nonresonant 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 and (ii) a detuning between the natural frequency of the system and the central frequency of the classical field induces revivals of quantum coherence.
    Physical Review A 02/2015; 91(2). DOI:10.1103/PhysRevA.91.022113 · 2.99 Impact Factor
  • Massimo Borrelli · Jonne V Koski · Sabrina Maniscalco · Jukka P Pekola
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    ABSTRACT: We theoretically investigate fluctuation relations in a classical incomplete measurement process where only partial information is available. The scenario we consider consists of two coupled single-electron boxes where one or both devices can undergo a nonequilibrium 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.
    Physical Review E 01/2015; 91(1-1):012145. DOI:10.1103/PhysRevE.91.012145 · 2.33 Impact Factor
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    F. Galve · R. Zambrini · S. Maniscalco
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    ABSTRACT: In this Letter we investigate Quantum Darwinism and the emergence of a classical world from the quantum one in connection with the spectral properties of the environment. We use a microscopic model of quantum environment in which, by changing a simple system parameter, we can modify the information back flow from environment into the system, and therefore its non-Markovian character. We show that the presence of memory effects hinders the emergence of classical objective reality. We conjecture that this phenomenon is connected to the absence of a measurement-scheme interpretation for quantum trajectories in the non-Markovian regime.
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    Jacopo Trapani · Matteo Bina · Sabrina Maniscalco · Matteo G. A. Paris
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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.
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    Massimo Borrelli · Jonne V. Koski · Sabrina Maniscalco · Jukka P. Pekola
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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.
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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. DOI:10.1038/srep05720 · 5.58 Impact Factor
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    Massimo Borrelli · Matteo Rossi · Chiara Macchiavello · Sabrina Maniscalco
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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). DOI:10.1103/PhysRevA.90.020301 · 2.99 Impact Factor
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    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). DOI:10.1142/S0219749914610061 · 0.99 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. DOI:10.1103/PhysRevLett.112.120404 · 7.51 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). DOI:10.1142/S1230161214400058 · 0.81 Impact Factor
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    Carole Addis · Bogna Bylicka · Dariusz Chruściński · Sabrina Maniscalco
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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.
    Physical Review A 02/2014; 90(5). DOI:10.1103/PhysRevA.90.052103 · 2.99 Impact Factor
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    Carole Addis · Gregoire Brebner · Pinja Haikka · Sabrina Maniscalco
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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.
    Physical Review A 11/2013; 89(2). DOI:10.1103/PhysRevA.89.024101 · 2.99 Impact Factor
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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

Publication Stats

2k Citations
233.48 Total Impact Points

Institutions

  • 2006–2015
    • University of Turku
      • • Department of Physics and Astronomy
      • • Department of Physiatrics
      Turku, Varsinais-Suomi, Finland
  • 2010–2014
    • Heriot-Watt University
      • • School of Engineering and Physical Sciences
      • • Department of Physics
      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
  • 2004–2005
    • University of KwaZulu-Natal
      • Department of Physics
      Durban, KwaZulu-Natal, South Africa