Universal joint-measurement uncertainty relation for error bars

We formulate and prove a new, universally valid uncertainty relation for the necessary error bar widths in any approximate joint measurement of position and momentum

Spatial Localization and Relativistic Transformation of Quantum Spins

The purity of a reduced state for spins that is pure in the rest frame will most likely appear to degrade because spin and momentum become mixed when viewed by a moving observer. We show that such a boost-induced decrease in spin purity observed in a moving reference frame is intrinsically related to the spatial localization properties of the wave package observed in the rest frame. Furthermore, we prove that, for any localized pure state with separable spin and momentum in the rest frame, its reduced density matrix for spins inevitably appears to be mixed whenever viewed from a moving reference frame.Comment: 5 pages, 1 figur

A comparison of direct and electric-current measurements in the Florida Current

Simultaneous measurements of surface velocity obtained in 1967 by means of geomagnetic electrokinetograph and free-instrument techniques aboard two ships in the Florida Current off Ft. Pierce, Florida have been compared . The results show a varying degree of agreement in magnitude across the stream and good agreement in direction. A surprising result is the high seabed conductance

Simultaneous Border-Collision and Period-Doubling Bifurcations

We unfold the codimension-two simultaneous occurrence of a border-collision bifurcation and a period-doubling bifurcation for a general piecewise-smooth, continuous map. We find that, with sufficient non-degeneracy conditions, a locus of period-doubling bifurcations emanates non-tangentially from a locus of border-collision bifurcations. The corresponding period-doubled solution undergoes a border-collision bifurcation along a curve emanating from the codimension-two point and tangent to the period-doubling locus here. In the case that the map is one-dimensional local dynamics are completely classified; in particular, we give conditions that ensure chaos.Comment: 22 pages; 5 figure

On the coexistence of position and momentum observables

We investigate the problem of coexistence of position and momentum observables. We characterize those pairs of position and momentum observables which have a joint observable

Neumark Operators and Sharp Reconstructions, the finite dimensional case

A commutative POV measure $F$ with real spectrum is characterized by the existence of a PV measure $E$ (the sharp reconstruction of $F$) with real spectrum such that $F$ can be interpreted as a randomization of $E$. This paper focuses on the relationships between this characterization of commutative POV measures and Neumark's extension theorem. In particular, we show that in the finite dimensional case there exists a relation between the Neumark operator corresponding to the extension of $F$ and the sharp reconstruction of $F$. The relevance of this result to the theory of non-ideal quantum measurement and to the definition of unsharpness is analyzed.Comment: 37 page

Исследование самопонимания этнокультурной идентичности в титульном армянском этносе и сопряженной армянской диаспоре в России

The study was supported by the State Committee for Science of the Ministry of Education and Science of the Republic of Armenia within the Armenian-Russian joint research project “The psychological aspect of the person’s self-understanding of national identity in the context of historical experience in the post-Soviet space (the study of young people of Russia and Armenia)” This paper presents generalized results of a two-year empirical study. The sample involved Armenian respondents from Armenia (310 persons) and Armenians residingin the Kuban region (307 persons). Diagnostic tools of the present study included: (a) a modified technique of “graph-schemes” by B. V. Kaigorodov; (b) method of semantic differential; (c) questionnaire by S. Schwarz and V. Bilski; and (d) techniques for studying types of self-interpretation by T. Singelis and T. DeCicco. Findings of the present study concern (a) a nucleus of ethnic normativity in Armenian youngpeople, (b) statistically significant differences in representations of an ethno-cultural ideal in the respondents of the titular Armenian ethnos and the Armenian diaspora, (c) elements of self-image in the context of ethno-cultural norms and values. Self-understanding of ethno-cultural identity in the titular ethnos had a number of features: (a) the national and the civil were closely associated with each other in the feeling of belonging to a nation, its historical past, and cultural originality; (b) therespondents of the titular ethnos perceived civic consciousness as a personal value. In the Armenian diaspora, the multiplicity of identities led to a sense of responsibility for various communities and comprehension of ethnic cohesion as a personal value; this was a distinctive feature of self-understanding of ethno-cultural identity in this group of respondents.В статье представлены обобщенные результаты двухлетнего эмпирического исследования, проведенного на выборке респондентов – армян из Армении (310 человек) и армян, перманентно проживающих на Кубани (307 человек), с использованием модифицированной автором методики «граф-схем» Б. В. Кайгородова, метода семантического дифференциала, опросника С. Шварца и В. Билски, методик исследования типов самоинтерпретации Т. Сингелис и Т. ДеЧикко. В результате исследования было выявлено ядро этнической нормативности у армянской молодежи, обнаружены статистически значимые различия у респондентов из титульного армянского этноса и диаспоры в представлениях об этнокультурном идеале, а также элементов образа Я в контексте этнокультурных норм и ценностей. В результате проведенного исследования установлено, что в титульном этносе особенность самопонимания этнокультурной идентичности заключается в том, что национальное и гражданское переплетены в чувстве принадлежности к народу, его историческому прошлому и культурному своеобразию; гражданственность воспринимается в качестве личностной ценности; в условиях диаспоры множественность идентичностей обуславливает такую особенность самопонимания этнокультурной идентичности, как осознание ответственности перед различными общностями и осмысление этнической сплоченности как личностной ценности

Barycentric decomposition of quantum measurements in finite dimensions

We analyze the convex structure of the set of positive operator valued measures (POVMs) representing quantum measurements on a given finite dimensional quantum system, with outcomes in a given locally compact Hausdorff space. The extreme points of the convex set are operator valued measures concentrated on a finite set of k \le d^2 points of the outcome space, d< \infty being the dimension of the Hilbert space. We prove that for second countable outcome spaces any POVM admits a Choquet representation as the barycenter of the set of extreme points with respect to a suitable probability measure. In the general case, Krein-Milman theorem is invoked to represent POVMs as barycenters of a certain set of POVMs concentrated on k \le d^2 points of the outcome space.Comment: !5 pages, no figure

An early Little Ice Age brackish water invasion along the south coast of the Caspian Sea (sediment of Langarud wetland) and its wider impacts on environment and people

Caspian Sea level has undergone significant changes through time with major impacts not only on the surrounding coasts, but also offshore. This study reports a brackish water invasion on the southern coast of the Caspian Sea constructed from a multi-proxy analysis of sediment retrieved from the Langarud wetland. The ground surface level of wetland is >6 m higher than the current Caspian Sea level (at -27.41 m in 2014) and located >11 km far from the coast. A sequence covering the last millennium was dated by three radiocarbon dates. The results from this new study suggest that Caspian Sea level rose up to at least -21.44 m (i.e. >6 m above the present water level) during the early Little Ice Age. Although previous studies in the southern coast of the Caspian Sea have detected a high-stand during the Little Ice Age period, this study presents the first evidence that this high-stand reached so far inland and at such a high altitude. Moreover, it confirms one of the very few earlier estimates of a high-stand at -21 m for the second half of the 14th century. The effects of this large-scale brackish water invasion on soil properties would have caused severe disruption to regional agriculture, thereby destabilizing local dynasties and facilitating a rapid Turko-Mongol expansion of Tamerlane’s armies from the east.N Ghasemi (INIOAS), V Jahani (Gilan Province Cultural Heritage and Tourism Organisation) and A Naqinezhad (University of Mazandaran), INQUA QuickLakeH project (no. 1227) and to the European project Marie Curie, CLIMSEAS-PIRSES-GA-2009-24751