Preserving the measure of compatibility between quantum states

In this paper after defining the abstract concept of compatibility-like functions on quantum states, we prove that every bijective transformation on the set of all states which preserves such a function is implemented by an either unitary or antiunitary operator.Comment: 11 pages, submitted for publicatio

k-Trails: Recognition, Complexity, and Approximations

The notion of degree-constrained spanning hierarchies, also called k-trails, was recently introduced in the context of network routing problems. They describe graphs that are homomorphic images of connected graphs of degree at most k. First results highlight several interesting advantages of k-trails compared to previous routing approaches. However, so far, only little is known regarding computational aspects of k-trails. In this work we aim to fill this gap by presenting how k-trails can be analyzed using techniques from algorithmic matroid theory. Exploiting this connection, we resolve several open questions about k-trails. In particular, we show that one can recognize efficiently whether a graph is a k-trail. Furthermore, we show that deciding whether a graph contains a k-trail is NP-complete; however, every graph that contains a k-trail is a (k+1)-trail. Moreover, further leveraging the connection to matroids, we consider the problem of finding a minimum weight k-trail contained in a graph G. We show that one can efficiently find a (2k-1)-trail contained in G whose weight is no more than the cheapest k-trail contained in G, even when allowing negative weights. The above results settle several open questions raised by Molnar, Newman, and Sebo

Исследование структуры древостоя на исторической экспериментальной площади

Защитные леса не подразумевают выборочных рубок, но выборочные рубки помогают поддерживать их наиболее эффективно. Так как раньше в Венгрии не было больших площадей регулируемых лесов, система выборочных рубок используется для перевода в эту категорию ранее одновозрастных лесов. Процесс трансформации очень длительный и может занять века. Трансформация лесного участка Sopron 182/B началась в 1937 г. и теперь находится на финальных стадиях. Разнообразно структурированный древостой позволяет нам анализировать процесс в реальном лесу, что может помочь на практике. Обработка данных пока на начальном этапе, и после корректировки позиций появится больше возможностей для применения ГИС-технологи

More frequencies of KUV 02464+3239

Preliminary results on KUV 02464+3239, a pulsating DA white dwarf are presented. Located near the red edge of the DAV instability strip, KUV 02464+3239 shows large amplitude and long period pulsation modes. Up to now only one mode was known from a 50-minute-long light curve. Our more extended observations allowed the identification of three additional frequencies. The presence of previously known harmonics were confirmed and weak subharmonics are also noticeable at some parts of the light curve. This suggests the dominance of nonlinear pulsation effects from time to time.Comment: 3 pages, 3 eps figures; has been accepted for publication in Astronomische Nachrichten (Vol. 8, 2007), proceedings of the British-Hungarian-French N+N+N Workshop for Young Researcher

Hints of incomplete thermalization in RHIC data

The large elliptic flow observed in Au-Au collisions at RHIC is often put forward as a compelling evidence for the formation of a strongly-interacting quark-gluon plasma. The main argument is that the measured elliptic flow is as large as the value given by fluid-dynamics models that assume complete thermalization. It is argued that this claim may not be justified, since a detailed examination of experimental data rather suggests that the system created is not fully equilibrated at the time when anisotropic flow develops.Comment: 8 pages, 2 eps-figures, Talk given at the Workshop on QGP Thermalization (QGPTH05), Vienna, 10-12 Aug 200

Generic stability of dissipative non-relativistic and relativistic fluids

The linear stability of the homogeneous equilibrium of non-relativistic fluids with mass flux and special relativistic fluids with the absolute value of the energy vector as internal energy is investigated. It is proved that the equilibrium is asymptotically stable in both cases due to purely thermodynamic restrictions; the only requirements are the thermodynamic stability and the nonnegativity of the transport coefficients.Comment: 22 page