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Search results for: quantum temporal correlations

Search results for: quantum temporal correlations

  • Entangled Histories vs. the Two-State-Vector Formalism - Towards a Better Understanding of Quantum Temporal Correlations

    Publication

    The Two-State-Vector formalism and the Entangled Histories formalism are attempts to betterunderstand quantum correlations in time. Both formalisms share some similarities, but they are notidentical, having subtle differences in their interpretation and manipulation of quantum temporalstructures. However, the main objective of this paper is to prove that, with appropriately definedscalar products, both formalisms can be...

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  • Are quantum correlations symmetric?

    Publication

    - QUANTUM INFORMATION & COMPUTATION - Year 2010

    We provide operational definition of symmetry of entanglement: An entangled state contains symmetric entanglement if its subsystems can be exchanged (swapped) by means of local operations and classical communication. We show that in general states have asymmetric entanglement. This allows to construct nonsymmetric measure of entanglement, and a parameter that reports asymmetry of entanglement contents of quantum state. We propose...

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  • Hybrid no-signaling-quantum correlations

    Publication

    - NEW JOURNAL OF PHYSICS - Year 2022

    Fundamental 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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  • Anomalous decay of quantum correlations of quantum-dot qubits

    Publication

    - PHYSICAL REVIEW A - Year 2013

    We 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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  • Thermodynamical approach to quantifying quantum correlations

    Publication

    - PHYSICAL REVIEW LETTERS - Year 2002

    We 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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  • Bipartite correlations in quantum resonance states

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  • No-local-broadcasting theorem for multipartite quantum correlations

    Publication

    We prove that the correlations present in a multipartite quantum state have an operational quantum character even if the state is unentangled, as long as it does not simply encode a multipartite classical probability distribution. Said quantumness is revealed by the new task of local broadcasting, i.e., of locally sharing preestablished correlations, which is feasible if and only if correlations are stricly classical. Our operational...

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  • Quantum correlations in one-dimensional Wigner molecules

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  • Quantum Correlations of a Few Bosons within a Harmonic Trap

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  • The decay of quantum correlations between quantum dot spin qubits and the characteristics of its magnetic-field dependence

    Publication

    - EPL-EUROPHYS LETT - Year 2014

    We 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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  • Electronic correlations in coherent transport through a two quantum dot system

    Publication

    - PHYSICAL REVIEW B - Year 2004

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  • Distributed correlations and information flows within a hybrid multipartite quantum-classical system

    Publication

    - PHYSICAL REVIEW A - Year 2015

    Understanding the non-Markovian mechanisms underlying the revivals of quantum entanglement in the presence of classical environments is central in the theory of quantum information. Tentative interpretations have been given by either the role of the environment as a control device or the concept of hidden entanglement. We address this issue from an information-theoretic point of view. To this aim, we consider a paradigmatic tripartite...

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  • Quantum entanglement in time

    Publication

    In 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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  • No Quantum Realization of Extremal No-Signaling Boxes

    Publication

    - PHYSICAL REVIEW LETTERS - Year 2016

    The study of quantum correlations is important for fundamental reasons as well as for quantum communication and information processing tasks. On the one hand, it is of tremendous interest to derive the correlations produced by measurements on separated composite quantum systems from within the set of all correlations obeying the no-signaling principle of relativity, by means of information-theoretic principles. On the other hand,...

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  • Blurred quantum Darwinism across quantum reference frames

    Publication

    Quantum Darwinism describes objectivity of quantum systems via their correlations with their environment--information that hypothetical observers can recover by measuring the environments. However, observations are done with respect to a frame of reference. Here, we take the formalism of [Giacomini, Castro-Ruiz, & Brukner. Nat Commun 10, 494 (2019)], and consider the repercussions on objectivity when changing quantum reference...

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  • All Nonclassical Correlations Can Be Activated into Distillable Entanglement

    Publication
    • M. Piani
    • S. Gharibian
    • G. Adesso
    • J. Calsamigilia
    • P. Horodecki
    • A. Winter

    - PHYSICAL REVIEW LETTERS - Year 2011

    We devise a protocol in which general nonclassical multipartite correlations produce a physically relevant effect, leading to the creation of bipartite entanglement. In particular, we show that the relative entropy of quantumness, which measures all nonclassical correlations among subsystems of a quantum system, is equivalent to and can be operationally interpreted as the minimum distillable entanglement generated between the system...

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  • Quantum entanglement

    Publication

    - REVIEWS OF MODERN PHYSICS - Year 2009

    All 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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  • Generic emergence of classical features in quantum Darwinism

    Publication

    - Nature Communications - Year 2015

    Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics:...

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  • Experimental certification of more than one bit of quantum randomness in the two inputs and two outputs scenario

    Publication

    - NEW JOURNAL OF PHYSICS - Year 2023

    One of the striking properties of quantum mechanics is the occurrence of the Bell-type non-locality. They are a fundamental feature of the theory that allows two parties that share an entangled quantum system to observe correlations stronger than possible in classical physics. In addition to their theoretical significance, non-local correlations have practical applications, such as device-independent randomness generation, providing...

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  • On symmetric extendibility of quantum states and its applications

    Publication

    - Year 2017

    This 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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  • Quantum-correlation breaking channels, broadcasting scenarios, and finite Markov chains

    Publication

    - PHYSICAL REVIEW A - Year 2012

    One of the classical results concerning quantum channels is the characterization of entanglementbreakingchannels [M. Horodecki et al., Rev. Math. Phys 15, 629 (2003)]. We address the questionwhether there exists a similar characterization on the level of quantum correlations which may gobeyond entanglement. The answer is fully affirmative in the case of breaking quantum correlationsdown to the, so called, QC (Quantum-Classical)...

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  • Local hidden–variable models for entangled quantum states

    Publication

    While entanglement and violation of Bell inequalities were initially thought to be equivalent quantum phenomena, we now have different examples of entangled states whose correlations can be described by local hidden-variable models and, therefore, do not violate any of the Bell inequalities. We provide an up-to-date overview of the existing literature regarding local hidden-variable models for entangled quantum states, in both...

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  • Quantum Steering Inequality with Tolerance for Measurement-Setting Errors: Experimentally Feasible Signature of Unbounded Violation

    Publication

    - PHYSICAL REVIEW LETTERS - Year 2017

    uantum steering is a relatively simple test for proving that the values of quantum-mechanical measurement outcomes come into being only in the act of measurement. By exploiting quantum correlations, Alice can influence — steer — Bob ’ s physical system in a way that is impossible in classical mechanics, as shown by the violation of steering inequalities. Demonstrating this and similar quantum effects for systems of increasing size,...

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  • Conjectured strong complementary-correlations tradeoff

    Publication
    • A. Grudka
    • M. Horodecki
    • P. Horodecki
    • R. Horodecki
    • W. Kłobus
    • Ł. Pankowski

    - PHYSICAL REVIEW A - Year 2013

    We conjecture uncertainty relations that restrict correlations between the results of measurements performed by two separate parties on a shared quantum state. The first uncertainty relation bounds the sum of two mutual informations when one party measures a single observable and the other party measures one of two observables. The uncertainty relation does not follow from the Maassen-Uffink uncertainty relation and is much stronger...

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  • Bound on Bell inequalities by fraction of determinism and reverse triangle inequality

    Publication
    • P. Joshi
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • R. Horodecki
    • B. Li
    • S. Szarek
    • T. Szarek

    - PHYSICAL REVIEW A - Year 2015

    It is an established fact that entanglement is a resource. Sharing an entangled state leads to nonlocal correlations and to violations of Bell inequalities. Such nonlocal correlations illustrate the advantage of quantum resources over classical resources. In this paper, we quantitatively study Bell inequalities with 2 × n inputs. As found in Gisin et al. [Int. J. Quantum. Inform. 05, 525 (2007)], quantum mechanical correlations...

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  • Characterizing the Performance of <span class="sc">xor</span> Games and the Shannon Capacity of Graphs

    Publication

    - PHYSICAL REVIEW LETTERS - Year 2014

    In this Letter we give a set of necessary and sufficient conditions such that quantum players of a two-party xor game cannot perform any better than classical players. With any such game, we associate a graph and examine its zero-error communication capacity. This allows us to specify a broad new class of graphs for which the Shannon capacity can be calculated. The conditions also enable the parametrization of new families of games...

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  • Elemental and tight monogamy relations in nonsignaling theories

    Publication

    - PHYSICAL REVIEW A - Year 2014

    Physical principles constrain the way nonlocal correlations can be distributed among distant parties. These constraints are usually expressed by monogamy relations that bound the amount of Bell inequality violation observed among a set of parties by the violation observed by a different set of parties. We prove here that much stronger monogamy relations are possible for nonsignaling correlations by showing how nonlocal correlations...

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  • Arithmetic Loophole in Bell's Theorem: Overlooked Threat to Entangled-State Quantum Cryptography

    Publication

    Bell’s theorem is supposed to exclude all local hidden-variable models of quantum correlations. However,an explicit counterexample shows that a new class of local realistic models, based on generalized arith-metic and calculus, can exactly reconstruct rotationally symmetric quantum probabilities typical oftwo-electron singlet states. Observable probabilities are consistent with the usual arithmetic employedby macroscopic observers...

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  • Progress towards a unified approach to entanglement distribution

    Publication

    - PHYSICAL REVIEW A - Year 2015

    Entanglement distribution is key to the success of secure communication schemes based on quantum mechanics, and there is a strong need for an ultimate architecture able to overcome the limitations of recent proposals such as those based on entanglement percolation or quantum repeaters. In this work we provide a broad theoretical background for the development of such technologies. In particular, we investigate the question of whether...

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  • Method for universal detection of two-photon polarization entanglement

    Publication
    • K. Bartkiewicz
    • P. Horodecki
    • K. Lemr
    • A. Miranowicz
    • K. Życzkowski

    - PHYSICAL REVIEW A - Year 2015

    Detecting and quantifying quantum entanglement of a given unknown state poses problems that are fundamentally important for quantum information processing. Surprisingly, no direct (i.e., without quantum tomography) universal experimental implementation of a necessary and sufficient test of entanglement has been designed even for a general two-qubit state. Here we propose an experimental method for detecting a collective universal...

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  • Entangled rendezvous: a possible application of Bell non-locality for mobile agents on networks

    Publication

    Rendezvous is an old problem of assuring that two or more parties, initially separated, not knowing the position of each other, and not allowed to communicate, are striving to meet without pre-agreement on the meeting point. This problem has been extensively studied in classical computer science and has vivid importance to modern and future applications. Quantum non-locality, like Bell inequality violation, has shown that in many...

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  • Analytical progress on symmetric geometric discord: Measurement-based upper bounds

    Publication

    - PHYSICAL REVIEW A - Year 2012

    Quantum correlations may be measured by means of the distance of the state to the subclass ofstates having well defined classical properties. In particular, a geometric measure of asymmetricdiscord [Daki´c et al., Phys. Rev. Lett. 105, 190502 (2010)] was recently defined as the Hilbert-Schmidt distance of a given two-qubit state to the closest classical-quantum (CQ) correlated state.We analyze a geometric measure of symmetric...

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  • Information content of systems as a physical principle

    Publication

    - PHYSICAL REVIEW A - Year 2017

    To 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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  • Trade-offs in multiparty Bell-inequality violations in qubit networks

    Publication

    - PHYSICAL REVIEW A - Year 2018

    Two overlapping bipartite binary input Bell inequalities cannot be simultaneously violated as this would contradict the usual no-signalling principle. This property is known as monogamy of Bell inequality violations and generally Bell monogamy relations refer to trade-offs between simultaneous violations of multiple inequalities. It turns out that multipartite Bell inequalities admit weaker forms of monogamies that allow for violations...

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  • Amplifying the Randomness of Weak Sources Correlated With Devices

    Publication

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Year 2017

    The problem of device-independent randomness amplification against no-signaling adversaries has so far been studied under the assumption that the weak source of randomness is uncorrelated with the (quantum) devices used in the amplification procedure. In this paper, we relax this assumption, and reconsider the original protocol of Colbeck and Renner using a Santha-Vazirani (SV) source. To do so, we introduce an SV-like condition...

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  • Continuum orbitals in low energy scattering of electrons from Ar, Kr, Xe, Rn and Og atoms

    Open Research Data

    The dataset includes relativistic continuum electron wave functions (continuum orbitals, continuum spinors) for elastic scattering of electrons from Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn) and Oganesson (Og) atoms, calculated using the Multiconfiguration Dirac-Hartree-Fock method (MCDHF), at very low electron energies (0.0001 - 0.001 eV). Only...

  • Chemical Pressure Tuning Magnetism from Pyrochlore to Triangular Lattices

    Publication
    • R. S. Dissanayaka Mudiyanselage
    • T. Klimczuk
    • D. Ni
    • R. J. Cava
    • W. Xie

    - INORGANIC CHEMISTRY - Year 2022

    Geometrically frustrated lattices combined with magnetism usually host quantum fluctuations that suppress magnetic orders and generate highly entangled ground states. Three-dimensionally (3D) frustrated magnets generally exist in the diamond and pyrochlore lattices, while two-dimensionally (2D) frustrated geometries contain Kagomé, triangular, and honeycomb lattices. In this work, we reported using chemical pressure to tune the magnetism...

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  • Postulates for measures of genuine multipartite correlations

    Publication

    - PHYSICAL REVIEW A - Year 2011

    A lot of research has been done on multipartite correlations. However, it seems strange thatthere is no denition of so called genuine multipartite correlations. In this paper we propose threereasonable postulates which each measure or indicator of genuine multipartite correlations (or gen-uine multipartite entanglement) should satisfy. We also introduce degree of correlations which givespartial characterization of multipartite...

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  • Broadcast copies reveal the quantumness of correlations

    Publication

    - PHYSICAL REVIEW A - Year 2009

    We study the quantumness of bipartite correlations by proposing a quantity that combines a measure of total correlations-mutual information-with the notion of broadcast copies-i.e., generally nonfactorized copies-of bipartite states. By analyzing how our quantity increases with the number of broadcast copies, we are able to classify classical, separable, and entangled states. This motivates the definition of the broadcast regularization...

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  • Zero-knowledge convincing protocol on quantum bit is impossible

    Publication

    - Quantum Journal - Year 2017

    It is one of fundamental features of quantum formalism that o n one hand it provides a new infor- mation processing resources and on the other hand puts funda mental constraints on the processing of quantum information implying “no-go” theorems for cloni ng [1–3], bit commitment [4, 5] and deleting [6] in quantum theory. Here we ask about possibilit y of “zero knowledge” scenario which, for its simplicity, can be considered as...

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  • Materials science. Quantum particle approach. 2022.

    e-Learning Courses
    • M. Bobrowski

    quantum methods for materials and molecular modeling.

  • Material Science Quantum Particle Approach 2021

    e-Learning Courses
    • M. Bobrowski

    quantum methods for materials and molecular modeling.

  • Materials science. Quantum particle approach. 2023.

    e-Learning Courses
    • M. Bobrowski

    Quantum ideas applied for particle systems and for chemical reactions.

  • Endoscopic Video Classification with the Consideration of Temporal Patterns

    The article describes a novel approach to automatic recognition and classification of diseases in endoscopic videos. Current directions of research in this field are discussed. Most presented methods focus on processing single frames and do not take into consideration the temporal relationship between continuous classifications. Existing approaches that consider the temporal structure of an incoming frame sequence are focused on...

  • Quantum randomness protected against detection loophole attacks

    Publication
    • P. A. Mironowicz
    • G. Cañas
    • J. Cariñe
    • E. S. Gómez
    • J. F. Barra
    • A. Cabello
    • G. B. Xavier
    • G. Lima
    • M. Pawłowski

    - Quantum Information Processing - Year 2021

    Device and semi-device-independent private quantum randomness generators are crucial for applications requiring private randomness. However, they are vulnerable to detection inefficiency attacks and this limits severely their usage for practical purposes. Here, we present a method for protecting semi-device-independent private quantum randomness generators in prepare-and-measure scenarios against detection inefficiency attacks....

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  • Introduction to quantum mechanics 2022/2023

    e-Learning Courses
    • S. Winczewski

    Introduction to quantum mechanics, kierunek: Nanotechnologia, specjalność: Nanostructures and computer simulations in material science, II stopień, semestr 1

  • Quantum Coherence as a Resource

    Publication
    • A. Streltsov
    • G. Adesso
    • M. B. Plenio

    - REVIEWS OF MODERN PHYSICS - Year 2017

    The coherent superposition of states, in combination with the quantization of observables, represents one of the most fundamental features that mark the departure of quantum mechanics from the classical realm. Quantum coherence in many-body systems embodies the essence of entanglement and is an essential ingredient for a plethora of physical phenomena in quantum optics, quantum information, solid state physics, and nanoscale thermodynamics....

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  • Human memory enhancement through electrical stimulation in the temporal cortex

    Publication
    • M. T. Kucewicz
    • B. M. Berry
    • L. R. Miller
    • F. Khadjevand
    • Y. Ezzyat
    • J. M. Stein
    • V. Kremen
    • B. H. Brinkmann
    • P. Wanda
    • M. R. Sperling... and 10 others

    - Brain: A Journal of Neurology - Year 2018

    Direct electrical stimulation of the human brain can elicit sensory and motor perceptions as well as recall of memories. Stimulating higher order association areas of the lateral temporal cortex in particular was reported to activate visual and auditory memory representations of past experiences (Penfield and Perot, 1963). We hypothesized that this effect could be used to modulate memory processing. Recent attempts at memory enhancement...

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  • Purely quantum superadditivity of classical capacities of quantum multiple access channels

    Publication

    We are studying classical capacities of quantum memoryless multiaccess channels in geometric terms and we are revealing a break of additivity of the Holevo-like capacity. This effect is a purely quantum mechanical one, since, as we point out, the capacity regions of all classical memoryless multiaccess channels are additive. It is the first such effect revealed in the field of classical information transmission via quantum channels.

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  • The Ellenbogen's “Matter as Software” Concept for Quantum Computer Implementation. C60 and X@C60 Molecules as Available Molecular Building Blocks (MBBs) for Tip-Based Nanofabrication (TBN) of Quantum Computing Devices

    Publication

    - Quantum Matter - Year 2015

    The TBN bottom-up strategy of building quantum devices from C60 and X@C60 MBBs is proposed as an extension of the Ellenbogen's “Matter as Software” idea to quantum information processing. The capped SW or DW CNT STM tip is considered as device for manipulating C60 and X@C60 molecules. In this article, the possibility of using easily available on the market C60 Fullerene and endohedral X@C60 molecules together with commercial CNT...

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