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  • Quantum Coherence as a Resource
    Publikacja
    • A. Streltsov
    • G. Adesso
    • M. B. Plenio

    - REVIEWS OF MODERN PHYSICS - Rok 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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  • Thermodynamical approach to quantifying quantum correlations
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 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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  • Direct estimation of linear and nonlinear functionals of quantum state
    Publikacja
    • A. Ekert
    • C. M. Alves
    • D. K. Oi
    • M. Horodecki
    • P. Horodecki
    • L. C. Kwek

    - PHYSICAL REVIEW LETTERS - Rok 2002

    We 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...

  • Dynamics of quantum entanglement
    Publikacja

    - PHYSICAL REVIEW A - Rok 2002

    A 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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  • Direct detection of quantum entanglement
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2002

    Basing 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.

  • General paradigm for distilling classical key from quantum states
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2009

    In 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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  • Optimization of Hydrogen - Evolving Photochemical Molecular Devices
    Publikacja
    • M. Pfeffer
    • T. Kowacs
    • M. Wachtler
    • J. Guthmuller
    • B. Dietzek
    • J. Vos
    • S. Rau

    - ANGEWANDTE CHEMIE-INTERNATIONAL EDITION - Rok 2015

    A molecular photocatalyst consisting of a RuII photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light-driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy...

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  • Generic emergence of classical features in quantum Darwinism
    Publikacja

    - Nature Communications - Rok 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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  • Quantifying Contextuality
    Publikacja
    • A. Grudka
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • R. Horodecki
    • P. Joshi
    • W. Kłobus
    • A. Wójcik

    - PHYSICAL REVIEW LETTERS - Rok 2014

    Contextuality is central to both the foundations of quantum theory and to the novel information processing tasks. Despite some recent proposals, it still faces a fundamental problem: how to quantify its presence? In this work, we provide a universal framework for quantifying contextuality. We conduct two complementary approaches: (i) the bottom-up approach, where we introduce a communication game, which grasps the phenomenon of...

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  • On thermal stability of topological qubit in Kitaev's 4D model
    Publikacja

    - OPEN SYSTEMS & INFORMATION DYNAMICS - Rok 2010

    We analyse stability of the four-dimensional Kitaev model-a candidate for scalable quantum memory - in finite temperature within the weak coupling Markovian limit. It is shown that, below a critical temperature, certain topological qubit observables X and Z possess relaxation times exponentially long in the size of the system. Their construction involves polynomial in system size algorithm which uses as an input the results of...

  • Dynamical description of quantum computing: generic nonlocality of quantumnoise
    Publikacja

    We 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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  • Structure of the Resource Theory of Quantum Coherence
    Publikacja
    • A. Streltsov
    • S. Rana
    • P. Boes
    • R. Eisert

    - PHYSICAL REVIEW LETTERS - Rok 2017

    Quantum 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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  • Towards Resource Theory of Coherence in Distributed Scenarios
    Publikacja

    - Physical Review X - Rok 2017

    The search for a simple description of fundamental physical processes is an important part of quantum theory. One example for such an abstraction can be found in the distance lab paradigm: if two separated parties are connected via a classical channel, it is notoriously difficult to characterize all possible operations these parties can perform. This class of operations is widely known as local operations and classical communication....

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  • Quantum origins of objectivity
    Publikacja

    - PHYSICAL REVIEW A - Rok 2015

    In 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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  • At the Limits of Criticality-Based Quantum Metrology: Apparent Super-Heisenberg Scaling Revisited
    Publikacja

    - Physical Review X - Rok 2018

    We address the question of whether the super-Heisenberg scaling for quantum estimation is indeed realizable. We unify the results of two approaches. In the first one, the original system is compared with its copy rotated by the parameter-dependent dynamics. If the parameter is coupled to the one-body part of the Hamiltonian, the precision of its estimation is known to scale at most as N−1 (Heisenberg scaling) in terms of the number...

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  • Objectivity in a Noisy Photonic Environment through Quantum State Information Broadcasting
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2014

    Recently, the emergence of classical objectivity as a property of a quantum state has been explicitly derived for a small object embedded in a photonic environment in terms of a spectrum broadcast form—a specific classically correlated state, redundantly encoding information about the preferred states of the object in the environment. However, the environment was in a pure state and the fundamental problem was how generic and robust...

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  • Low-dimensional bound entanglement with one-way distillable cryptographic key
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2008

    In this paper, we provide a class of bound entangled states that have positive distillable secure key rate. The smallest state of this kind is 4 circle times 4, which shows that peculiar security contained in bound entangled states does not need high-dimensional systems. We show that for these states a positive key rate can be obtained by one-way Devetak-Winter (DW) protocol. Subsequently, the volume of bound entangled key-distillable...

  • Quantum key distribution based on private states: Unconditional security over untrusted channels with zero quantum capacity
    Publikacja
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • D. Leung
    • J. Oppenheim

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2008

    In 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...

  • Self-healing mechanism of metallopolymers investigated by QM/MM simulations and Raman spectroscopy
    Publikacja
    • S. Kupfer
    • L. Zedler
    • J. Guthmuller
    • S. Bode
    • M. Hager
    • U. Schubert
    • J. Popp
    • S. Gräfe
    • B. Dietzek

    - PHYSICAL CHEMISTRY CHEMICAL PHYSICS - Rok 2014

    The thermally induced self-healing mechanisms in metallopolymers based on bisterpyridine complexes of iron(II) sulfate and cadmium(II) bromide, respectively, were studied by means of combined quantum mechanical/molecular mechanical (QM/MM) simulations and Raman spectroscopy. Two possible healing schemes, one based on a decomplexation of the cross-linking complexes and a second one relying on the dissociation of ionic clusters,...

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

    - PHYSICAL REVIEW A - Rok 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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  • Resonance-Raman spectro-electrochemistry of intermediates in molecular artificial photosynthesis of bimetallic complexes
    Publikacja
    • L. Zedler
    • J. Guthmuller
    • I. Rabelo
    • S. Kupfer
    • S. Krieck
    • M. Schmitt
    • J. Popp
    • S. Rau
    • B. Dietzek

    - CHEMICAL COMMUNICATIONS - Rok 2014

    The sequential order of photoinduced charge transfer processes and accompanying structure changes were analyzed by UV-vis and resonance-Raman spectroscopy of intermediates of a Ru(II) based photocatalytic hydrogen evolving system obtained by electrochemical reduction.

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  • Concurrence in arbitrary dimensions
    Publikacja

    - JOURNAL OF MODERN OPTICS - Rok 2002

    Podano definicję kwantowej zgodności dla stanów dwucząstkowych w przypadku dowolnych skończonych wymiarów przestrzeni Hilberta. Wprowadzono także bi-zgodność, której znikanie stanowi warunek konieczny i dostateczny separowalności stanów dwucząstkowych.

  • Calculation of adiabatic potentials of Li2
    Publikacja

    Informujemy o adiabatycznych krzywych energii potencjalnej cząsteczki litu. Nasze krzywe są stabelowane według odległości międzyatomowej od 3,2 a0 do 88a0. Porównujemy nasze wyniki teoretyczne z wynikami obliczonymi przez innych autorów oraz krzywymi energii potencjalnej wyprowadzonymi z eksperymentów. W naszym podejściu używamy metody konfiguracji wzajemnego oddziaływania, gdzie tylko elektrony walencyjne atomu Li są traktowane...

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  • Realistic noise-tolerant randomness amplification using finite number of devices
    Publikacja
    • F. Brandão
    • R. Ramanathan
    • A. Grudka
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • T. Szarek
    • H. Wojewódka

    - Nature Communications - Rok 2016

    Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification...

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  • Simulations of hydro-fracking in rock mass at meso-scale using fully coupled DEM/CFD approach

    The paper deals with two-dimensional (2D) numerical modelling of hydro-fracking (hydraulic fracturing) in rocks at the meso-scale. A numerical model was developed to characterize the properties of fluid-driven fractures in rocks by combining the discrete element method (DEM) with computational fluid dynamics (CFD). The mechanical behaviour of the rock matrix was simulated with DEM and the behaviour of the fracturing fluid flow...

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  • Flavin mononucleotide fluorescence intensity decay in concentrated aqueous solutions
    Publikacja

    - CHEMICAL PHYSICS LETTERS - Rok 2007

    Czasowo-rozdzielone widma absorpcji i fluorescencji FMN w roztworach wodnych zostały zmierzone dla szerokiego zakresu stężeń. Pokazano, że zaniki fluorescencji są silnie przyśpieszone przez obecność dimerów FMN, które stanowią niedoskonałe pułapki energii wzbudzenia. Wyniki doświadczalne porównano z rezultatami symulacji Monte-Carlo, uwzględniającej powrotny transfer energii od pułapek do donorów, stwierdzając dobrą zgodność modelu...

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  • An Assessment of RASSCF and TDDFT Energies and Gradients on an Organic Donor−Acceptor Dye Assisted by Resonance Raman Spectroscopy
    Publikacja

    - Journal of Chemical Theory and Computation - Rok 2013

    The excitation energies and gradients in the ground and the first excited state of a novel donor−(π- bridge)−acceptor 4-methoxy-1,3-thiazole-based chromophore were investigated by means of MS-RASPT2/RASSCF and TDDFT in solution. Within both methods, the excitation energies strongly depend on the employed equilibrium structures, whose differences can be rationalized in terms of bond length alternation indexes. It is shown that functionals with...

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  • A few steps more towards NPT bound entanglement
    Publikacja

    - IEEE TRANSACTIONS ON INFORMATION THEORY - Rok 2010

    In this paper, existence of bound entangled states with nonpositive partial transpose (NPT) is considered. As one knows, existence of such states would in particular imply nonadditivity of distillable entanglement. Moreover, it would rule out a simple mathematical description of the set of distillable states. The particular state, known to be 1-copy nondistillable and supposed to be bound entangled, is considered. The problem of...

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  • Photophysics of Ru(II) Dyads Derived from Pyrenyl-Substitued Imidazo[4,5-f][1,10]phenanthroline Ligands.
    Publikacja
    • C. Reichardt
    • M. Pinto
    • M. Wachtler
    • M. Stephenson
    • S. Kupfer
    • T. Sainuddin
    • J. Guthmuller
    • S. A. Mcfarland
    • B. Dietzek

    - JOURNAL OF PHYSICAL CHEMISTRY A - Rok 2015

    The photophysics of a series of Ru(II) dyads based on the 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]-phenanthroline ligand was investigated. The ability of these metal complexes to intercalate DNA and induce cell death upon photoactivation makes them attractive photosensitizers for a range of photobiological applications, including photodynamic therapy. In the present study, time-resolved transient absorption and emission spectroscopy...

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  • Comparison of simplified sum-over-state expressions to calculate resonance Raman intensities including Franck-Condon and Herzberg-Teller effects
    Publikacja

    Sum-over-state (SOS) expressions to simulate absorption spectroscopy and resonance Raman (RR) scattering including Franck-Condon (FC) and Herzberg-Teller (HT) effects are described. Starting from the general SOS method, several simplified SOS formulae are derived. In particular, within the so-called independent mode displaced harmonic oscillator model, it is shown that including the vibronic structure in the absorption and RR spectra...

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  • Correlation experiments in nonlinear quantum mechanics
    Publikacja

    - PHYSICS LETTERS A - Rok 2002

    Pokazano w jaki sposób należy obliczać wieloczasowe i wielocząstkowe funkcje korelacyjne w nieliniowej mechanice kwantowej, aby zagwarantować lokalność formalizmu.

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  • Quantum communication complexity advantage implies violation of a Bell inequality
    Publikacja

    - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA - Rok 2016

    We obtain a general connection between a quantum advantage in communication complexity and non-locality. We show that given any protocol offering a (sufficiently large) quantum advantage in communication complexity, there exists a way of obtaining measurement statistics which violate some Bell inequality. Our main tool is port-based teleportation. If the gap between quantum and classical communication complexity can grow arbitrarily...

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  • Long-Distance FRET Analysis: A Monte Carlo Simulation Study
    Publikacja

    - JOURNAL OF PHYSICAL CHEMISTRY B - Rok 2011

    Zaproponowano nową metodę na rozszerzenie zakresu stosowalności rezonansowego transferu energii (FRET) przetestowaną przy pomocy metody Monte Carlo. Otrzymane rezultaty dowodzą, że wydajność procesu FRET może być znacząco zwiększona w porównaniu z wydajnością pojedynczego akceptora, gdy dla ustalonej od donora umieścimy układ blisko siebie położonych akceptorów na makromolekule. Z drugiej strony metoda ta umożliwia zwiększenie...

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  • Concentration-Dependent Fluorescence Properties of Rhodamine 6G in Titanium Dioxide and Silicon Dioxide Nanolayers
    Publikacja

    - Journal of Physical Chemistry C - Rok 2012

    Wytworzono cienkie warstwy zawierające rodaminę 6G w dwutlenku tytanu (R6G/TiO2) i w dwutlenku krzemu (R6G/SiO2) stosując metodę zol-żel. Badane były dwa rodzaje matryc, w których domieszkowano barwnik rodamina 6G (R6G) o różnych koncentracjach. Został stwierdzony istotny wpływ koncentracji barwnika na widma absorpcji i emisji oraz na czasowo rozdzielone widma fluorescencji. W szczególności stwierdzono znacznie mniejszą zdolność...

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  • Objectivity in the non-Markovian spin-boson model
    Publikacja

    - PHYSICAL REVIEW A - Rok 2017

    Objectivity constitutes one of the main features of the macroscopic classical world. An important aspect of the quantum-to-classical transition issue is to explain how such a property arises from the microscopic quantum theory. Recently, within the framework of open quantum systems, there has been proposed such a mechanism in terms of the so-called spectrum broadcast structures. These are multipartite quantum states of the system...

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  • Roadmap on dynamics of molecules and clusters in the gas phase
    Publikacja
    • H. Zettergren
    • A. Domaracka
    • T. Schlathölter
    • P. Bolognesi
    • S. Díaz-Tendero
    • M. Łabuda
    • S. Tosic
    • S. Maclot
    • P. Johnsson
    • A. Steber... i 34 innych

    - EUROPEAN PHYSICAL JOURNAL D - Rok 2021

    This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty orders of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity...

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  • Quantum metrology: Heisenberg limit with bound entanglement
    Publikacja

    - PHYSICAL REVIEW A - Rok 2015

    Quantum 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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  • Necessary and Sufficient Condition for State-Independent Contextual Measurement Scenarios
    Publikacja

    - PHYSICAL REVIEW LETTERS - Rok 2014

    The problem of identifying measurement scenarios capable of revealing state-independent contextuality in a given Hilbert space dimension is considered. We begin by showing that for any given dimension d and any measurement scenario consisting of projective measurements, (i) the measure of contextuality of a quantum state is entirely determined by its spectrum, so that pure and maximally mixed states represent the two extremes...

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  • Influence of Protonation State on the Excited State Dynamics of a Photobiologically Active Ru(II) Dyad
    Publikacja
    • C. Reichardt
    • T. Sainuddin
    • M. WäCHTLER
    • S. Monro
    • S. Kupfer
    • J. Guthmuller
    • S. Gräfe
    • S. A. Mcfarland
    • B. Dietzek

    - JOURNAL OF PHYSICAL CHEMISTRY A - Rok 2016

    The influence of ligand protonation on the photophysics of a ruthenium (Ru) dyad bearing the 2-(1-pyrenyl)-1H-imidazo[4,5-f][1,10]-phenanthroline (ippy) ligand was investigated by time-resolved transient absorption spectroscopy. It was found that changes in the protonation state of the imidazole group led to changes in the electronic configuration of the lowest lying excited state. Formation of the fully deprotonated imidazole...

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  • A Novel Ru(II) Polypyridine Black Dye Investigated by Resonance Raman Spectroscopy and TDDFT Calculations
    Publikacja
    • J. Guthmuller
    • S. Kupfer
    • M. Wachtler
    • J. Popp
    • B. Dietzek
    • L. Gonzalez

    - Journal of Physical Chemistry C - Rok 2012

    The optical properties of a new(bipyridine)2Ru(4H-imidazole) complex presenting a remarkablebroad absorption in the visible range are investigated. Thestrong overlap of the absorption with the solar radiationspectrum renders the studied complex promising as a blackabsorber and hence as a starting structure for applications inthe field of dye-sensitized solar cells. The correlations betweenstructural and electronic features for...

  • On structural physical approximations and entanglement breaking maps
    Publikacja

    - JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL - Rok 2011

    Very recently, a conjecture saying that the so-called structural physical approximations (SPAs) to optimal positive maps (optimal entanglement witnesses) give entanglement breaking (EB) maps (separable states) has been posed (Korbicz et al 2008 Phys. Rev. A 78 062105). The main purpose of this contribution is to explore this subject. First, we extend the set of entanglement witnesses supporting the conjecture. Then, we ask whether...

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

    - PHYSICAL REVIEW LETTERS - Rok 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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  • Waves Along Fractal Coastlines: From Fractal Arithmetic to Wave Equations
    Publikacja

    Beginning with addition and multiplication intrinsic to a Koch-type curve, we formulate and solve wave equation describing wave propagation along a fractal coastline. As opposed to examples known from the literature, we do not replace the fractal by the continuum in which it is embedded. This seems to be the first example of a truly intrinsic description of wave propagation along a fractal curve. The theory is relativistically...

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  • Quantum-state transfer in spin chains via isolated resonance of terminal spins
    Publikacja

    - PHYSICAL REVIEW A - Rok 2014

    We 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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  • Synthesis and characterization of ruthenium and rhenium dyes with phosphonate anchoring groups
    Publikacja

    - DALTON TRANSACTIONS - Rok 2016

    Re(L1)–Re(L3), a series of rhenium(I) tricarbonyl chloride complexes with bpy-R2 derivatives L1–L3 (bpy = 2,2′-bipyridine, R represents the substitution at the 4- and 4′-positions), and their corresponding trishomoleptic Ru(L1)3–Ru(L3)3 as well as heteroleptic ruthenium(II) complexes Ru(tbbpy)2(L1) and Ru(tbbpy)2(L2) have been synthesized and characterized. Their applicability as immobilizable metal–organic chromophores in solar...

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  • Randomness Amplification under Minimal Fundamental Assumptions on the Devices
    Publikacja
    • R. Ramanathan
    • F. Brandão
    • K. Horodecki
    • M. Horodecki
    • P. Horodecki
    • H. Wojewódka

    - PHYSICAL REVIEW LETTERS - Rok 2016

    Recently, the physically realistic protocol amplifying the randomness of Santha-Vazirani sources producing cryptographically secure random bits was proposed; however, for reasons of practical relevance, the crucial question remained open regarding whether this can be accomplished under the minimal conditions necessary for the task. Namely, is it possible to achieve randomness amplification using only two no-signaling components...

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  • Positron scattering on molecular hydrogen: Analysis of experimental and theoretical uncertainties
    Publikacja

    - PHYSICAL REVIEW A - Rok 2015

    Experiments performed in recent years on positron scattering from molecular hydrogen indicated a rise of the total cross section in the limit of zero energy, but essentially disagree on the amplitude of this rise. Mitroy and collaborators [J.-Y. Zhang et al., Phys. Rev. Lett. 103, 223202 (2009)] predicted a scattering length somewhat different from values deduced experimentally. Using a Markov chain Monte Carlo modified effective...

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  • Monitoring of the Process of System Information Broadcasting in Time

    One 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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  • Method for universal detection of two-photon polarization entanglement
    Publikacja
    • K. Bartkiewicz
    • P. Horodecki
    • K. Lemr
    • A. Miranowicz
    • K. Życzkowski

    - PHYSICAL REVIEW A - Rok 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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  • Theoretical Assessment of Excited State Gradients and Resonance Raman Intensities for the Azobenzene Molecule

    The ground state geometries and vibrational frequencies as well as the excitation energies and excited state gradients of the S 1(nπ*) and S 2(ππ * ) states of trans - and cis -azobenzene are investigated by several DFT methods, namely B3LYP, PBE, M06-2X, CAM-B3LYP, and ω B97X. Excited state properties and in particular gradients are also assessed using the wave function based methods EOM-CCSD and RASPT2/RASSCF. Comparison with...

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