Spin dependent conductance of a quantum dot side attached to topological superconductors as a probe of Majorana fermion states

Spin-polarized transport through a quantum dot side attached to a topological superconductor and coupled to a pair of normal leads is discussed in Coulomb and Kondo regimes. For discussion of Coulomb range equation of motion method with extended Hubbard I approximation is used and Kondo regime is analyzed by Kotliar-Ruckenstein slave boson approach. Apart from the occurrence of zero bias anomaly the presence of Majorana states reflects also in splitting of Coulomb lines. In the region of Coulomb borders the spin dependent negative differential conductance is observed. Due to the low energy scale of Kondo effect this probe allows for detection of Majorana states even for extremely weak coupling with topological wire. In this range no signatures of Majorana states appear in Coulomb blockade dominated transport.Comment: 3 pages, 3 figure

on the discursive space of political struggles in Poland

The aim of this paper is to reconstruct the structure of discursive positions pertaining to the relationship between Poland and the European Union (EU). Such a problematization draws on the assumption that Europe is always understood in relation to the nation state and, in turn, the image of the latter is explicitly referred to or can be inferred from the vision of the EU. The analysis of the empirical data has revealed three discursive positions which organize the production of meaning and govern the strategies of representation. The first position represents the EU as a chance for the further modernization of Poland. The second position perceives the EU as the game of interests between sovereign nation states. The task of the nation state is to benefit from cooperation within an extra-state structure and to retain maximum sovereignty at the same time. The third identifies the EU as “a threat” hostile to the nation state and its interests. The chain of equivalence connects the EU with almost all negative social phenomena. The discursive analytical assumptions adopted in the paper help to show how the same topics and words (chance, threat, interests, nation, state, sovereignty, “Europe of fatherlands”, and modernization) acquire different meanings in the context of particular interpretations of other words

Persistence Bag-of-Words for Topological Data Analysis

Persistent homology (PH) is a rigorous mathematical theory that provides a robust descriptor of data in the form of persistence diagrams (PDs). PDs exhibit, however, complex structure and are difficult to integrate in today's machine learning workflows. This paper introduces persistence bag-of-words: a novel and stable vectorized representation of PDs that enables the seamless integration with machine learning. Comprehensive experiments show that the new representation achieves state-of-the-art performance and beyond in much less time than alternative approaches.Comment: Accepted for the Twenty-Eight International Joint Conference on Artificial Intelligence (IJCAI-19). arXiv admin note: substantial text overlap with arXiv:1802.0485

Uwarunkowania legitymizacji władzy w systemach autorytarnych. Casus państw Azji Centralnej

Legitimacy along with co-optation and repression are the three main pillars of the stability of autocratic regimes. Explanation of their relative stability should take into account the complex relationships between these variables. The elites of authoritarian regimes systematically formulate legitimacy claims in order to justify their power, and the processes of institutionalization and effective distribution of these claims depends on a number of factors and mechanisms. The purpose of this paper is to analyze these factors and mechanisms of legitimacy contributing to the stability of authoritarian states by drawing on the example of Central Asian republics.Legitymizacja wraz z kooptacją oraz represją stanowi trzy zasadnicze filary stabilności reżimu autokratycznego, a wyjaśnianie mechanizmów trwałości powinno uwzględniać skomplikowane relacje pomiędzy wymienionymi zmiennymi. Elity reżimów autorytarnych systematycznie formułują legitymizacyjne roszczenia mające usprawiedliwiać ich władzę, a proces ich skutecznej dystrybucji oraz instytucjonalizacji zależy od szeregu warunków i mechanizmów. Zadaniem niniejszego tekstu jest analiza wybranych warunków efektywności i mechanizmów legitymizacji w państwach autorytarnych, w oparciu o przykłady pochodzące z krajów Azji Centralnej