Search
Filters
total: 591
Search results for: QUANTUM
-
Measuring quantum entanglement without prior state reconstruction.
PublicationWykazano, że w przypadku dwóch kubitów splątanie formowania może być mierzone bez rekonstrukcji stanu kwantowego.
-
Quantum aspects of semantic analysis and symbolic artificial intelligence.
PublicationNowoczesne podejścia do analizy semantycznej, jeśli przeformułować je w język przestrzeni Hilberta, ujawniają formalne struktury znane z mechaniki kwantowej. Podobna sytuacja występuje w rozproszonych reprezentacjach struktur poznawczych rozwijanych na użytek sieci neuronowych. W pracy przyglądamy się różnicom i podobieństwom owych teorii do kwantowej teorii informacji.
-
Lasing modes of infinite periodic chain of quantum wires
Publication -
Quantum Entanglement of Two Harmonically Trapped Dipolar Particles
Publication -
A model of a tunable quantum dot in a semiconducting carbon nanotube
Publication -
Quantum chemical modeling of electrochromism of tungsten oxide films
Publication -
Dynamical nonlocality in quantum time via modular operators
PublicationWe formalize the concept of the modular energy operator within the Page and Wootters timeless framework. As a result, this operator is elevated to the same status as the more studied modular operators of position and momentum. In analogy with dynamical nonlocality in space associated with the modular momentum, we introduce and analyze the nonlocality in time associated with the modular energy operator. Some applications of our...
-
Zero range potential approximation in quantum scattering problems
Publication -
Robustness of quantum-randomness expansion protocols in the presence of noise
PublicationIn this paper we investigate properties of several randomness generation protocols in the device independent framework. Using Bell-type inequalities it is possible to certify that the numbers generated by an untrusted device are indeed random. We present a selection of certificates which guarantee two bits of randomness for each run of the experiment in the noiseless case and require the parties to share a maximally entangled state....
-
Polymerization of chloro-p-xylylenes, quantum-chemical study
PublicationThe p-xylylene monomers of parylene N, C and D have similar high polymerization reactivity. For effective copolymerization processes this fact is basically a draw- back and for instance the copolymerization with styrene doesn't go at all (Corley et al. J Pol Sc 13(68):137156, 1954). Substitution of terminal hydrogen atoms by chlorine atoms reduces reactivity dramatically. 7,7,8,8-tetrachloro-p- xylylene and 2,5,7,7,8,8-hexachloro-p-xylylene...
-
Quantum issues in diagnostics of marine energy machines and devices
PublicationW artykule podjęto zagadnienie możliwości uwzględniania części dorobku mechaniki kwantowej w diagnostyce okrętowych urządzeń energetycznych. Wykazano, że są zbieżne spostrzeżenia mechaniki kwantoweji diagnostyki technicznej uzyskane w obszarze wiedzy z zakresu badań empirycznych. Uzasadniono konieczność wykonywania podczas badań empirycznych, nie tylko rachunku błędów, lecz także określania niedokładności wyników badań (pomiarów)...
-
Direct measurement of nonlinear properties of bipartite quantum states
PublicationNieliniowe własności stanów kwantowych, takie jak entropia, splątania, określają ilość ważnych fizycznych źródeł i są często używane w informatyce kwantowej. Na ogół są one obliczane z pełnego opisu stanu kwantowego, pomimo tego, że zależą od niewielkiej ilości parametrów opisujących dany stan. Wyciągamy nielokalną i nieliniową wielkość, mianowicie entropię Renyi, z lokalnych pomiarów dwóch par fotonów splątanych polaryzacyjnie.
-
Multiacces quantum communication and product higher rank numerical range
PublicationIn the present paper we initiate the study of the product higher rank numerical range. The latter, being a variant of the higher rank numerical range, is a natural tool for study- ing a construction of quantum error correction codes for multiple access channels. We review properties of this set and relate it to other numerical ranges, which were recently introduced in the literature. Further, the concept is applied to the construction...
-
Quantum communication complexity advantage implies violation of a Bell inequality
PublicationWe 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...
-
Efficient bounds on quantum-communication rates via their reduced variants
PublicationWe investigate one-way communication scenarios where Bob operating on his component can transfer some subsystem to the environment. We define reduced versions of quantum-communication rates and, further, prove upper bounds on a one-way quantum secret key, distillable entanglement, and quantum-channel capacity by means of their reduced versions. It is shown that in some cases they drastically improve their estimation.
-
Quantum strategies for rendezvous and domination tasks on graphs with mobile agents
PublicationThis paper explores the application of quantum nonlocality, a renowned and unique phenomenon acknowledged as a valuable resource. Focusing on an alternative application, we demonstrate its quantum advantage for mobile agents engaged in specific distributed tasks without communication. The research addresses the significant challenge of rendezvous on graphs and introduces a distributed task for mobile agents grounded in the graph...
-
Analytical studies of spectrum broadcast structures in quantum Brownian motion
PublicationSpectrum 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...
-
Multi-criterion, evolutionary and quantum decision making in complex systems
PublicationMulti-criterion, evolutionary and quantum decision making supported by the Adaptive Quantum-based Multi-criterion Evolutionary Algorithm (AQMEA) has been considered for distributed complex systems. AQMEA had been developed to the task assignment problem, and then it has been applied to underwater vehicle planning as another benchmark three-criterion optimization problem. For evaluation of a vehicle trajectory three criteria have...
-
Directed percolation effects emerging from superadditivity of quantum networks
PublicationEntanglement-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...
-
Hybrid quantum-classical approach for atomistic simulation of metallic systems
PublicationThe learn-on-the-fly (LOTF) method [G. Csanyi et al., Phys. Rev. Lett. 93, 175503 (2004)] serves to seamlessly embed quantum-mechanical computations within a molecular-dynamics framework by continual local retuning of the potential's parameters so that it reproduces the quantum-mechanical forces. In its current formulation, it is suitable for systems where the interaction is short-ranged, such as covalently bonded semiconductors....
-
Statistical properties of a modified standard map in quantum and classical regimes
PublicationWe present a model—a modified standard map. This model has interesting properties that allow quantum–classical correspondences to be studied. For some range of parameters in the classical phase space of this model, there exist large accelerator modes. We can create a family of maps that have large accelerator modes.
-
General paradigm for distilling classical key from quantum states
PublicationIn 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...
-
Sharp transitions in low-number quantum dots Bayesian magnetometry
PublicationWe consider Bayesian estimate of static magnetic field, characterized by a prior Gaussian probability distribution, in systems of a few electron quantum dot spins interacting with infinite temperature spin environment via hyperfine interaction. Sudden transitions among optimal states and measurements are observed. Usefulness of measuring occupation levels is shown for all times of the evolution, together with the role of entanglement...
-
Quantum mechanical which-way experiment with an internal degree of freedom
PublicationFor 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...
-
Formation of carbon monoxide by radiative association: a quantum dynamical study
PublicationRate coefficients for the formation of carbon monoxide (CO) by radiative association of carbon and oxygen atoms are computed using quantum dynamical simulations. At temperatures above 10 K CO radiative association is dominated by C(3P) and O(3P) approaching on the A1Π potential energy curve. The rate coefficient is estimated as k=A(T/300 K)αexp−β/T with A= 1.39 × 10−18 cm3 s−1, α=−0.016 and β= 92.2 for temperatures between 6 and...
-
Device-independent quantum key distribution based on measurement inputs
PublicationWe provide an analysis of a family of device-independent quantum key distribution (QKD) protocols that has the following features. (a) The bits used for the secret key do not come from the results of the measurements on an entangled state but from the choices of settings. (b) Instead of a single security parameter (a violation of some Bell inequality) a set of them is used to estimate the level of trust in the secrecy of the key....
-
The optimized Rayleigh–Ritz scheme for determining the quantum-mechanical spectrum
Publication -
Correlation and Entanglement in Elliptically Deformed Two-Electron Quantum Dots
Publication -
On entaglement distillation and quantum error correction of unknown states and channels.
PublicationBadano niezmienniczości splątania kwantowego oraz pojemności kwantowego kanału ze względu na ewentualną utratę informacji o pojedynczej kopii kwantowego stanu. Pokazano, że jeżeli dany kwantowy kanał ma pewne pojemności niezerowe, to odpowiadające mu stany posiadają niezerowe destylowalne splątanie. Postawiono pewne otwarte problemy dotyczące destylowalności splątania.
-
Self-Calibrating Electronic Controller for Satellite Quantum Entanglement Source
Publication -
Pressure- and temperature-driven phase transitions in HgTe quantum wells
Publication -
Quantum chemical modelling of the process of lithium insertion into WO3 films
Publication -
Imitating Quantum Probabilities: Beyond Bell’s Theorem and Tsirelson Bounds
PublicationLocal hidden-variable model of singlet-state correlations discussed in M. Czachor, Acta Phys. Polon. A 139, 70, is shown to be a particular case of an infinite hierarchy of local hidden-variable models based on an infinite hierarchy of calculi. Violation of Bell-type inequalities can be interpreted as a `confusion of languages' problem, a result of mixing different but neighboring levels of the hierarchy. Mixing of non-neighboring...
-
The quantum free energy barrier for hydrogen vacancy diffusion in Na3AlH6
Publication -
Nuclear quantum effects in a HIV/cancer inhibitor: The case of ellipticine
Publication -
Spectroscopic and quantum chemical study of phthalocyanines with 1,4,7-trioxanonyl moieties
Publication -
Nuclear quantum effects in a HIV/cancer inhibitor: The case of ellipticine
Publication -
Quantum states representing perfectly secure bits are always distillable
PublicationW pracy pokazano, że ostatnio wprowadzone stany kwantowe reprezentujące perfekcyjnie bezpieczny bit klucza kryptograficznegooraz ich wielocząstkowe i wielowymiarowe uogólnienia zawsze reprezentują destylowalne splątanie. Podano ograniczenia dolne na wielkość destylowalnego splątania. Ponadto podano alternatywny dowód faktu, że koszt splątania jest ograniczeniem górnym na wielkość destylowalnego klucza kryptograficznego w dwucząstkowym...
-
On the distillation of cryptographic key from multipartie entangled quantum states
PublicationCelem pracy było uzupełnienie ogólnego paradygmatu destylacji bezpiecznego klucza kryptograficznego z dwucząstkowych stanów splątanych, a w szczegolności znalezienie nowych konstrukcji stanów kwantowych o splątaniu związanym z niezerowym destylowanym kluczem kryptograficznym. Kolejnym celem pracy było uogólnienie powyższego paradygmatu dwucząstkowego na przypadek wielu cząstek. W szczególności sformułowanie definicji wielocząstkowych...
-
The issues of quantum in empirical research on machines and other power systems
PublicationW pracy uzasadniono, że w badaniach naukowych systemów empirycznych, zwłaszcza maszyn jak również i innych urządzeń energetycznych, należy uwzględnić istniejącą w ich eksploatacji przypadkowość i nieprzewidywalność zdarzeń. Nawiązano do osiągnięć mechaniki kwantowej wskazując na wynikający z nich postulat, że wielkości nazywane komplementarnymi, mają istotną własność, która polega na tym, że niemożliwy jest jednoczesny i zarazem...
-
MOLECULAR AND QUANTUM ACOUSTICS. ANNUAL JOURNAL
Journals -
Semiconductor Physics Quantum Electronics & Optoelectronics
Journals -
A new look at two polymorphic crystal structures of dibenzoylmethane: relationship between the crystal packing and the hydrogen atom position revealed by quantum chemistry and quantum crystallography methods
Publication -
Unconditional privacy over channels which cannot convey quantum information
PublicationQuantum cryptography enables one to verify that the state of the quantum system has not been tampered with and thus one can obtain privacy regardless of the power of the eavesdropper. All previous protocols relied on the ability to faithfully send quantum states or equivalently to share pure entanglement. Here we show this need not be the case-one can obtain verifiable privacy even through some channels which cannot be used to...
-
Tip-Based Nanofabrication as a Rapid Prototyping Tool for Quantum Science and Technology
PublicationTip-Based Nanofabication as a Rapid Prototyping Tool for Quantum Science and Technology discusses the development of cantilevered nanotips techniques of quantum devices prototyping and how they evolved from scanning probe microscopy. Also covered are the advantages and future prospects of atomic resolution capability and how to use this enabling technology as a rapid prototyping tool for quantum science and technology.
-
Quantum-correlation breaking channels, broadcasting scenarios, and finite Markov chains
PublicationOne 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)...
-
Quantum corrections to 4 model solutions and applications to Heisenberg chain dynamics
PublicationThe Heisenberg spin chain is considered in φ^4 model approximation. Quantum corrections to classical solutions of the one-dimensional φ^4 model within the correspondent physics are valuated with account of rest d − 1 dimensions of a d-dimensional theory. A quantization of the model is considered in terms of space- time functional integral. The generalized zeta-function formalism is used to renormalize and evaluate the functional...
-
Experimental certification of an informationally complete quantum measurement in a device-independent protocol
PublicationMinimal informationally complete positive operator-valued measures (MIC-POVMs) are special kinds of measurement in quantum theory in which the statistics of their d2-outcomes are enough to reconstruct any d-dimensional quantum state. For this reason, MIC-POVMs are referred to as standard measurements for quantum information.Here, we report an experiment with entangled photon pairs that certifies, for what we believe is the first...
-
Connections between Mutually Unbiased Bases and Quantum Random Access Codes
PublicationWe present a new quantum communication complexity protocol, the promise--Quantum Random Access Code, which allows us to introduce a new measure of unbiasedness for bases of Hilbert spaces. The proposed measure possesses a clear operational meaning and can be used to investigate whether a specific number of mutually unbiased bases exist in a given dimension by employing Semi--Definite Programming techniques.
-
The photocurrent quantum efficiency dependence on the applied voltage in organic solar cells
PublicationWe 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...