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Wyszukujesz frazę "Horodecki, Paweł." wg kryterium: Autor


Tytuł:
Leaf litter decomposition dynamics on reclaimed post-mining site conditions
Dynamika dekompozycji liści drzew w warunkach rekultywowanych gruntów pokopalnianych
Autorzy:
Horodecki, Paweł
Współwytwórcy:
Jagodziński, Andrzej M. Promotor
Opis:
[4], 40 stron + załączniki 3 publikacje : ryc., w tym kol., tab. ; 30 cm ; bibliografia. Praca doktorska wykonana w Pracowni Ekologii Instytutu Dendrologii Polskiej Akademii Nauk
Dostawca treści:
RCIN - Repozytorium Cyfrowe Instytutów Naukowych
Książka
Tytuł:
Probing the limits of quantum theory with quantum information at subnuclear scales
Autorzy:
Eckstein, Michał
Horodecki, Paweł
Opis:
Modern quantum engineering techniques enabled successful foundational tests of quantum mechanics. Yet, the universal validity of quantum postulates is an open question. Here we propose a new theoretical framework of Q-data tests, which recognizes the established validity of quantum theory, but allows for more general—‘post-quantum’—scenarios in certain physical regimes. It can accommodate a large class of models with modified quantum wave dynamics, correlations beyond entanglement or general probabilistic postulates. We discuss its experimental implementation suited to probe the nature of strong nuclear interactions. In contrast to the present accelerator experiments, it shifts the focus from high-luminosity beam physics to individual particle coherent control.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
The experiment paradox in physics
Autorzy:
Eckstein, Michał
Horodecki, Paweł
Opis:
Modern physics is founded on two mainstays: mathematical modelling and empirical verification. These two assumptions are prerequisite for the objectivity of scientific discourse. Here we show, however, that they are contradictory, leading to the ‘experiment paradox’. We reveal that any experiment performed on a physical system is—by necessity—invasive and thus establishes inevitable limits to the accuracy of any mathematical model. We track its manifestations in both classical and quantum physics and show how it is overcome ‘in practice’ via the concept of environment. We argue that the unravelled paradox induces a new type of ‘ontic’ underdetermination, which has deep consequences for the methodological foundations of physics.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Quantum-state transfer in spin chains via isolated resonance of terminal spins
Autorzy:
Machnikowski, Paweł
Horodecki, Paweł
Korzekwa, Kamil
Opis:
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 on demand. We also show that the amount of information leaking into the central part of the chain is small throughout the whole transfer process (which protects the information sent from being eavesdropped) and can be controlled by the magnitude of the external magnetic field.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Multiaccess quantum communication and product higher rank numerical range
Autorzy:
Demianowicz, Maciej
Życzkowski, Karol
Horodecki, Paweł
Opis:
In 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 [M.-D. Choi et al., Rep. Math. Phys. 58, 77 (2006); Lin. Alg. Appl. 418, 828 (2006)], is a natural tool for studying 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 of codes for bi-unitary two-access channels with a hermitian noise model. Analytical techniques for both outerbounding the product higher rank numerical range and determining its exact shape are developed for this case. Finally, the reverse problem of constructing a noise model for a given product range is considered.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Hawking radiation and the quantum marginal problem
Autorzy:
Eckstein, Michał
Horodecki, Paweł
Aurell, Erik
Opis:
In 1974 Steven Hawking showed that black holes emit thermal radiation, which eventually causes them to evaporate. The problem of the fate of information in this process is known as the "black hole information paradox". Two main types of resolution postulate either a fundamental loss of information in Nature — hence the breakdown of quantum mechanics — or some sort of new physics, e.g. quantum gravity, which guarantee the global preservation of unitarity. Here we explore the second possibility with the help of recent developments in continuous-variable quantum information. Concretely, we employ the solution to the Gaussian quantum marginal problem to show that the thermality of all individual Hawking modes is consistent with a global pure state of the radiation. Surprisingly, we find out that the mods of radiation of an astrophysical black hole are thermal until the very last burst. In contrast, the single-mode thermality of Hawking radiation originating from microscopic black holes, expected to evaporate through several quanta, is not excluded, though there are constraints on modes' frequencies. Our result paves the way towards a systematic study of multi-mode correlations in Hawking radiation.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Quantum black holes as solvents
Autorzy:
Eckstein, Michał
Horodecki, Paweł
Aurell, Erik
Opis:
Almost all of the entropy in the universe is in the form of Bekenstein-Hawking (BH) entropy of super-massive black holes. This entropy, if it satisfes Boltzmann’s equation S = log N , hence represents almost all the accessible phase space of the Universe, somehow associated to objects which themselves fll out a very small fraction of ordinary three-dimensional space. Although time scales are very long, it is believed that black holes will eventually evaporate by emitting Hawking radiation, which is thermal when counted mode by mode. A pure quantum state collapsing to a black hole will hence eventually re-emerge as a state with strictly positive entropy, which constitutes the famous black hole information paradox. Expanding on a remark by Hawking we posit that BH entropy is a thermodynamic entropy, which must be distinguished from information-theoretic entropy. The paradox can then be explained by information return in Hawking radiation. The novel perspective advanced here is that if BH entropy counts the number of accessible physical states in a quantum black hole, then the paradox can be seen as an instance of the fundamental problem of statistical mechanics. We suggest a specifc analogy to the increase of the entropy in a solvation process. We further show that the huge phase volume (N ), which must be made available to the universe in a gravitational collapse, cannot originate from the entanglement between ordinary matter and/or radiation inside and outside the black hole. We argue that, instead, the quantum degrees of freedom of the gravitational feld must get activated near the singularity, resulting in a fnal state of the ‘entangled entanglement’ form involving both matter and gravity.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Five open problems in quantum information theory
Autorzy:
Rudnicki, Łukasz
Horodecki, Paweł
Życzkowski, Karol
Opis:
We identify five selected open problems in the theory of quantum information, which are rather simple to formulate, are well studied in the literature, but are technically not easy. As these problems enjoy diverse mathematical connections, they offer a huge breakthrough potential. The first four concern existence of certain objects relevant for quantum information, namely a family of symmetric informationally complete generalized measurements in an infinite sequence of dimensions, mutually unbiased bases in dimension six, measurements saturating multiparameter Cramér-Rao bound and bound entangled states with negative partial transpose. The fifth problem requires checking whether a certain state of a two-ququart system is two-copy distillable.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł

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