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Wyniki wyszukiwania dla: quantum information science
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Quantum entanglement
PublikacjaAll our former experience with application of quantum theory seems to say that what is predicted by quantum formalism must occur in the laboratory. But the essence of quantum formalism-entanglement, recognized by Einstein, Podolsky, Rosen, and Schrödinger-waited over 70 years to enter laboratories as a new resource as real as energy. This holistic property of compound quantum systems, which involves nonclassical correlations between...
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Long-distance quantum communication over noisy networks without long-time quantum memory
PublikacjaThe problem of sharing entanglement over large distances is crucial for implementations of quantum cryptography. A possible scheme for long-distance entanglement sharing and quantum communication exploits networks whose nodes share Einstein-Podolsky-Rosen (EPR) pairs. In Perseguers et al. [Phys. Rev. A 78, 062324 (2008)] the authors put forward an important isomorphism between storing quantum information in a dimension D and transmission...
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Postbiotics in oncology: science or science fiction?
PublikacjaThe gut microbiome has been increasingly understood to play a critical role in carcinogenesis and cancer disease progression. The most recent research advancements have shown that different tools of microbiota manipulation contribute to gut microbiome–immune–oncology axis modulation, offering exciting opportunities for targeted interventions aimed at improving the efficacy of established anti-cancer therapy. Postbiotics are a new...
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Quantum key distribution based on private states: Unconditional security over untrusted channels with zero quantum capacity
PublikacjaIn this paper, we prove unconditional security for a quantum key distribution (QKD) protocol based on distilling pbits (twisted ebits) from an arbitrary untrusted state that is claimed to contain distillable key. Our main result is that we can verify security using only public communication-via parameter estimation of the given untrusted state. The technique applies even to bound-entangled states, thus extending QKD to the regime...
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On symmetric extendibility of quantum states and its applications
PublikacjaThis dissertation is focused on analysis of the symmetric extendibility of quantum states and its applications in the quantum information theory, with special attention paid to the area of quantum entanglement distillation, quantum channels theory, quantum security, and monogamy of quantum entanglement in time. We analyze geometry of the set of symmetric extendible states, i.e. such states that possess symmetric extensions and...
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MOST Wiedzy jako narzędzie promocji potencjału naukowo-badawczego uczelni wyższej
PublikacjaRozwój Internetu wpłynął na wiele aspektów naszego życia. Pośród wielu z nich zrewolucjonizował sposób komunikacji. Pochodną tego jest zmiana sposobu przekazywania wszelkiego rodzaju wiedzy. Ogromne znaczenie mają przeszukiwane źródła wiedzy, ich jakość i dostępność. W związku z tym, w obecnych czasach, o potencjale naukowym uczelni wyższej stanowią, obok pracowników w nich zatrudnionych, przede wszystkim zgromadzone bazy wiedzy...
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Anomalous decay of quantum correlations of quantum-dot qubits
PublikacjaWe study the evolution of quantum correlations, quantified by the geometric discord, of two excitonic quantum-dot qubits under the influence of the phonon environment. We show that the decay of these correlations differs substantially from the decay of entanglement. Instead of displaying sudden-death-type behavior, the geometric discord shows a tendency to undergo transitions between different types of decay, is sensitive to nonlocal...
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Quantum metrology: Heisenberg limit with bound entanglement
PublikacjaQuantum entanglement may provide a huge boost in the precision of parameter estimation. However, quantum metrology seems to be extremely sensitive to noise in the probe state. There is an important still open question: What type of entanglement is useful as a resource in quantum metrology? Here we raise this question in relation to entanglement distillation. We provide a counterintuitive example of a family of bound entangled states...
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Monitoring of the Process of System Information Broadcasting in Time
PublikacjaOne of the problems of quantum physics is how a measurement turns quantum, noncopyable data, towards copyable classical knowledge. We use the quantum state discrimination in a central system model to show how its evolution leads to the broadcasting of the information, and how orthogonalization and decoherence factors allow us to monitor the distance of the state in question to the one perfectly broadcasting information, in any...
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Quantum entanglement in time
PublikacjaIn this paper we present a concept of quantum entanglement in time in a context of entangled consistent histories. These considerations are supported by presentation of necessary tools closely related to those acting on a space of spatial multipartite quantum states. We show that in similarity to monogamy of quantum entanglement in space, quantum entanglement in time is also endowed with this property for a particular history....
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Quantum origins of objectivity
PublikacjaIn spite of all of its successes, quantum mechanics leaves us with a central problem: How does nature create a bridge from fragile quanta to the objective world of everyday experience? Here we find that a basic structure within quantum mechanics that leads to the perceived objectivity is a so-called spectrum broadcast structure. We uncover this based on minimal assumptions, without referring to any dynamical details or a concrete...
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The Ellenbogen's "Matter as Software" Concept for Quantum Computer Implementation: III. Selection of X@C60 Molecular Building Blocks (MBBs) for Tip-Based Nanofabrication (TBN) of Trapped Neutral Atom Quantum Computing Devices
PublikacjaThe selection of guest atoms X of X@C60 MBBs for TBN of trapped neutral atom quantum computing devices is reported. Assuming the all-optical quantum computing as a final target stage, the two criteria are most important: the charge q accumulated on the C60 host must be as low as possible, and the atom X must have one or more available excited states within the band falling into the low energy window of neutral C60 molecule electronic...
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Żółte barwniki organiczne w XIX-wiecznych farbach Jana Matejki - identyfikacja substancji barwiących, nośników, oraz wypełniaczy
PublikacjaNaturalne barwniki organiczne można znaleźć w wielu obiektach dziedzictwa kulturowego. Identyfikacja substancji barwiących obecnych w farbach historycznych dostarcza istotnych informacji dla wielu specjalistów zaangażowanych w naukę o sztuce. Identyfikacja składu farb pozwala na zastosowanie odpowiednich procedur dotyczących renowacji i konserwacji historycznych dzieł sztuki. Informacje te pozwalają na ich renowację zgodnie z decyzjami...
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Generic appearance of objective results in quantum measurements
PublikacjaMeasurement is of central interest in quantum mechanics as it provides the link between the quantum world and the world of everyday experience. One of the features of everyday experience is its robust, objective character, contrasting the delicate nature of quantum systems. Here we analyze in a completely model-independent way the celebrated von Neumann measurement process, using recent techniques of information flow, studied in...
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Information content of systems as a physical principle
PublikacjaTo explain the conceptual gap between classical and quantum and other, hypothetical descriptions of the world, several principles have been proposed. So far, all these principles have not explicitly included the uncertainty relation. Here we introduce an information content principle ( ICP ) which represents a constrained uncertainty principle. The principle, by taking into account the encoding and decoding properties of a single physical...
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Evaluation of ChatGPT Applicability to Learning Quantum Physics
PublikacjaChatGPT is an application that uses a large language model. Its purpose is to generate answers to various questions as well as provide information, help solve problems and participate in conversations on a wide range of topics. This application is also widely used by students for the purposes of learning or cheating (e.g., writing essays or programming codes). Therefore, in this contribution, we evaluate the ability of ChatGPT...
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Information transfer during the universal gravitational decoherence
PublikacjaRecently Pikovski et al. (Nat Phys 11:668, 2015) have proposed in an intriguing universal decoherence mechanism, suggesting that gravitation may play a conceptually important role in the quantum-to-classical transition, albeit vanishingly small in everyday situations. Here we analyze information transfer induced by this mechanism. We show that generically on short time-scales, gravitational decoherence leads to a redundant information...
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Hybrid no-signaling-quantum correlations
PublikacjaFundamental investigations in non-locality have shown that while the no-signaling principle alone is not sufficient to single out the set of quantum non-local correlations, local quantum mechanics and no-signaling together exactly reproduce the set of quantum correlations in the two-party Bell scenario. Here, we introduce and study an intermediate hybrid no-signaling quantum set of non-local correlations that we term HNSQ in the...
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Special Issue: Recent Advances in Corrosion Science
PublikacjaThe dynamic development of the global industry and growing demand for new material technologies generates constantly increasing problems regarding premature material degradation and the requirement to determine corrosion mechanisms and to develop new protection/evaluation approaches. This Special Issue, “Recent Advances in Corrosion Science”, brings together fourteen articles and one review, providing a snapshot of the recent activity...
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Relating Information Culture to Information Policies and Management Strategies
PublikacjaBusiness and information managers have struggled to meet several challenges in aligning information strategies and business cultures. The consequences of a misalignment or misfit of strategy and culture are well known in business literature, and better guidance on how to better align strategy and culture is needed. This means expanding the puzzle to align business and information cultures, align business and information strategies,...
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The symmetric extendibility of quantum states
PublikacjaStudies on the symmetric extendibility of quantum states have become particularly important in the context of the analysis of one-way quantum measures of entanglement, and the distillability and security of quantum protocols. In this paper we analyze composite systems containing a symmetric extendible part, with particular attention devoted to the one-way security of such systems. Further, we introduce a new one-way entanglement...
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Karolina Lademann mgr
OsobyCurriculum vitae
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Dynamical description of quantum computing: generic nonlocality of quantumnoise
PublikacjaWe develop a dynamical non-Markovian description of quantum computing in the weak-coupling limit, in the lowest-order approximation. We show that the long-range memory of the quantum reservoir (such as the 1/t4 one exhibited by electromagnetic vacuum) produces a strong interrelation between the structure of noise and the quantum algorithm, implying nonlocal attacks of noise. This shows that the implicit assumption of quantum error...
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Direct detection of quantum entanglement
PublikacjaBasing on positive maps separability criterion we propose the experimentally viable, direct detection of quantum entanglement. It is efficient and does not require any a priori knowledge about the state. For two qubits it provides a sharp (i.e., “if and only if”) separability test and estimation of amount of entanglement. We view this method as a new form of quantum computation, namely, as a decision problem with quantum data structure.
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Quantum privacy witness
PublikacjaWhile it is usually known that the mean value of a single observable is enough to detect entanglement or its distillability, the counterpart of such an approach in the case of quantum privacy has been missing. Here we develop the concept of a privacy witness, i.e., a single observable that may detect the presence of the secure key even in the case of bound entanglement. Then we develop the notion of secret-key estimation based...
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Dynamical objectivity in quantum Brownian motion
PublikacjaClassical objectivity as a property of quantum states —a view proposed to explain the observer-independent character of our world from quantum theory, is an important step in bridging the quantum-classical gap. It was recently derived in terms of spectrum broadcast structures for small objects embedded in noisy photon-like environments. However, two fundamental problems have arisen: a description of objective motion and applicability...
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Structure of the Resource Theory of Quantum Coherence
PublikacjaQuantum coherence is an essential feature of quantum mechanics which is responsible for the departure between the classical and quantum world. The recently established resource theory of quantum coherence studies possible quantum technological applications of quantum coherence, and limitations that arise if one is lacking the ability to establish superpositions. An important open problem in this context is a simple characterization...
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Analytical studies of spectrum broadcast structures in quantum Brownian motion
PublikacjaSpectrum broadcast structures are a new and fresh concept in the quantum-to-classical transition, introduced recently in the context of decoherence and the appearance of objective features in quantum mechanics. These are specific quantum state structures, responsible for the objectivization of the decohered state of a system. Recently, they have been demonstrated by means of the well-known quantum Brownian motion model of the recoilless...
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Adaption of Open Science Paradigm at Gdańsk University of Technology
PublikacjaThe paper describes the basic principles standing behind Open Access and will try to dispel the doubts behind them. Further the solution adapted by the Gdańsk University of Technology is presented. Later on the systems that the University uses and means of their integration into a complex Open Science platform are described. Finally the procedures needed to publish a document in the repository alongside the University's policy...
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System information propagation for composite structures
PublikacjaWe study in details decoherence process of a spin register, coupled to a spin environment. We use recently developed methods of information transfer study in open quantum systems to analyze information flow between the register and its environment. We show that there are regimes when not only the register decoheres effectively to a classical bit string, but this bit string is redundantly encoded in the environment, making it available...
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The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence
PublikacjaWe address the question of the role of quantum correlations beyond entanglement in the context of quantum magnetometry. We study the evolution of the rescaled variant of the geometric quantum discord of two electron-spin qubits interacting with an environment of nuclear spins via the hyperfine interaction. We have found that quantum correlations display a strong magnetic-field sensitivity which can be utilized for decoherence-driven...
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Nonadditivity of quantum and classical capacities for entanglement breaking multiple-access channels and the butterfly network
PublikacjaWe analyze quantum network primitives which are entanglement breaking. We show superadditivity of quantum and classical capacity regions for quantum multiple-access channels and the quantum butterfly network. Since the effects are especially visible at high noise they suggest that quantum information effects may be particularly helpful in the case of the networks with occasional high noise rates. The present effects provide a qualitative...
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Approach to security assessment of critical infrastructures' information systems
PublikacjaThis study presents an approach to the security assessment of the information systems of critical infrastructures. The approach is based on the faithful reconstruction of the evaluated information system in a computer security laboratory followed by simulations of possible threats against the system. The evidence collected during the experiments, stored and organised using a proprietary system InSAW, may later be used for the creation...
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Decoherence-free communication over multiaccess quantum channels
PublikacjaIn this paper we consider decoherence-free communication over multiple access and k-user quantum channels. First, we concentrate on a hermitian unitary noise model U for a two-access bi-unitary channel and show that in this case a decoherence-free code exists if the space of Schmidt matrices of an eigensubspace of U exhibits certain properties of decomposability. Then, we show that our technique is also applicable for generic random unitary...
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Directed percolation effects emerging from superadditivity of quantum networks
PublikacjaEntanglement-induced nonadditivity of classical communication capacity in networks consisting of quantum channels is considered. Communication lattices consisting of butterfly-type entanglement-breaking channels augmented, with some probability, by identity channels are analyzed. The capacity superadditivity in the network is manifested in directed correlated bond percolation which we consider in two flavors: simply directed and...
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Dynamics of quantum entanglement
PublikacjaA model of discrete dynamics of entanglement of a bipartite quantum state is considered. It involves a global unitary dynamics of the system and periodic actions of local bistochastic or decaying channel. For initially pure states the decay of entanglement is accompanied by an increase of von Neumann entropy of the system. We observe and discuss revivals of entanglement due to unitary interaction of subsystems. For some mixed states...
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The Ellenbogen's "Matter as Software" Concept for Quantum Computer Implementation: II Bonding Between the C60 and X@C60 Molecules as Available Molecular Building Blocks (MBBs) for Tip-Based Nanofabrication (TBN) of Quantum Computing Devices
PublikacjaThe binding energy, BE of the X@C60-X@C60 homodimer and the X@C60-Y@C60 heterodimer resulting from the bond formation between the occupied X@C60 MBB and the C60 molecule was studied by means of semiempirical PM7 calculations, where X and Y denote atoms from H to Bi, excluding Tc and lanthanides. All possible combinations of N = 68 guest atoms were considered, which resulted in K = 2346 of different calculated dimers of (X@C60-Y@C60)...
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A simple test for quantum channel capacity
PublikacjaBased on state and channel isomorphism we point out that semidefiniteprogramming can be used as a quick test for nonzero one-way quantum channelcapacity. This can be achieved by searching for symmetric extensions of statesisomorphic to a given quantum channel. With this method we provide examplesof quantum channels that can lead to high entanglement transmission but stillhave zero one-way capacity, in particular, regions of symmetric...
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General paradigm for distilling classical key from quantum states
PublikacjaIn this paper, we develop a formalism for distilling aclassical key from a quantum state in a systematic way, expandingon our previous work on a secure key from bound entanglement(Horodecki et al., 2005). More detailed proofs, discussion, andexamples are provided of the main results. Namely, we demonstratethat all quantum cryptographic protocols can be recast in away which looks like entanglement theory, with the only changebeing...
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Multi-criterion decision making in distributed systems by quantum evolutionary algorithms
PublikacjaDecision making by the AQMEA (Adaptive Quantum-based Multi-criterion Evolutionary Algorithm) has been considered for distributed computer systems. AQMEA has been extended by a chromosome representation with the registry of the smallest units of quantum information. Evolutionary computing with Q-bit chromosomes has been proofed to characterize by the enhanced population diversity than other representations, since individuals represent...
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Quantum-state transfer in spin chains via isolated resonance of terminal spins
PublikacjaWe propose a quantum-state transfer protocol in a spin chain that requires only the control of the spins at the ends of the quantum wire. The protocol is to a large extent insensitive to inhomogeneity caused by local magnetic fields and perturbation of exchange couplings. Moreover, apart from the free evolution regime, it allows one to induce an adiabatic spin transfer, which provides the possibility of performing the transfer...
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Introduction to quantum mechanics
Kursy Online -
Advanced Modeling of Management Processes in Information Technology
PublikacjaThis book deals with the issues of modeling management processes of information technology and IT projects while its core is the model of information technology management and its component models (contextual, local) describing initial processing and the maturity capsule as well as a decision-making system represented by a multi-level sequential model of IT technology selection, which acquires a fuzzy rule-based implementation...
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Quantum mechanical which-way experiment with an internal degree of freedom
PublikacjaFor a particle travelling through an interferometer, the trade-off between the available which-way information and the interference visibility provides a lucid manifestation of the quantum mechanical wave-particle duality. Here we analyse this relation for a particle possessing an internal degree of freedom such as spin. We quantify the trade-off with a general inequality that paints an unexpectedly intricate picture of wave-particle...
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Distributed representation of information on cyclic events
PublikacjaA representation of information on cyclic events has been proposed which is advantageous for computing environments where a distributed set of Receivers reacts to cyclic events generated by distributed sources. In such scenario no immanent central information repository exist on event timing or volume. Receivers are able to learn the event cycles without communicating with each other, merely on the basis of the fact that an event...
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Direct estimation of linear and nonlinear functionals of quantum state
PublikacjaWe present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of...
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Thermodynamical approach to quantifying quantum correlations
PublikacjaWe consider the amount of work which can be extracted from a heat bath using a bipartite state ρ shared by two parties. In general it is less then the amount of work extractable when one party is in possession of the entire state. We derive bounds for this “work deficit” and calculate it explicitly for a number of different cases. In particuar, for pure states the work deficit is exactly equal to the distillable entanglement of...
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Social responsibility of universities - the example of AGH University of Science and Technology
PublikacjaThe key question here is how to achieve a symbiotic relationship between the university and its environment. The evolution of the Polish higher education system since 1990 shows how the mutual relations between the university and its surroundings may change over time. The conclusions published in the OECD report on higher education are juxtaposed with the description of the status quo of the Polish universities and compared with...
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The photocurrent quantum efficiency dependence on the applied voltage in organic solar cells
PublikacjaWe demonstrate that our recently reported model (Szmytkowski 2007 J. Phys. D: Appl. Phys. 40 3352) of the photocurrent quantum efficiency in organic semiconductors explains the external quantum efficiency dependence on the electric field in organic solar cells. This effect can be explained by taking into account that the photogeneration of charge carriers occurs via the electron-hole pair dissociation and the space charge effects...
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Quantum structure in competing lizard communities
PublikacjaAlmost two decades of research on applications of the mathematical formalism of quantum theory as a modeling tool in domains different from the micro-world has given rise to many successful applications in situations related to human behavior and thought, more specifically in cognitive processes of decision-making and the ways concepts are combined into sentences. In this article, we extend this approach to animal behavior, showing...