Relaxation of superflow in a network: an application to the dislocation model of supersolidity of helium crystals

We have considered the dislocation network model for the supersolid state in He-4 crystals. In difference with uniform 2D and 3D systems, the temperature of superfluid transition T_c in the network is much smaller than the degeneracy temperature T_d. It is shown that a crossover into a quasi superfluid state occurs in the temperature interval between T_c and T_d. Below the crossover temperature the time of decay of the flow increases exponentially under decrease of the temperature. The crossover has a continuous character and the crossover temperature does not depend on the density of dislocations.Comment: Corrected typo

Competing ideologies of Russia's civil society

Many analysts and public opinion makers in the West conflate the notions of Russia’s non-systemic liberal opposition and the country’s civil society. Indeed, despite garnering the support of a minority of Russia’s population, non-systemic liberal opposition represents a well-organized civic group with a clearly articulated agenda and the ability to take action. Yet, does Russia’s civil society end there? A closer look at the country’s politics shows that Russia has a substantial conservative-traditionalist faction that has also developed agenda for action and formulated opinions. This group is anti-liberal rather than illiberal ideologically and pro-strong state/pro a geopolitically independent Russia rather than pro-Kremlin politically. The interaction between liberal and conservative civic groups represents the battle of meanings, ideas, and ethics, and ultimately determines the future trajectory of Russia’s evolution. Thus, the analysis of Russia’s civil society must represent a rather more nuanced picture than a mere study of the liberal non-systemic opposition. This article will examine the complexity of Russia’s civil society scene with reference to the interplay between the liberal opposition and conservative majority factions. The paper will argue that such complexity stems from ideological value pluralism that falls far beyond the boundaries of the liberal consensus, often skewing our understanding of political practice in Russia

Non-dissipative drag of superflow in a two-component Bose gas

A microscopic theory of a non-dissipative drag in a two-component superfluid Bose gas is developed. The expression for the drag current in the system with the components of different atomic masses, densities and scattering lengths is derived. It is shown that the drag current is proportional to the square root of the gas parameter. The temperature dependence of the drag current is studied and it is shown that at temperature of order or smaller than the interaction energy the temperature reduction of the drag current is rather small. A possible way of measuring the drag factor is proposed. A toroidal system with the drag component confined in two half-ring wells separated by two Josephson barriers is considered. Under certain condition such a system can be treated as a Bose-Einstein counterpart of the Josephson charge qubit in an external magnetic field. It is shown that the measurement of the difference of number of atoms in two wells under a controlled evolution of the state of the qubit allows to determine the drag factor.Comment: 13 pages, 3 figures. This preprint is extended and substantially revised variant of related preprint cond-mat/040456

Fluid Models for Kinetic Effects on Coherent Nonlinear Alfven Waves. II. Numerical Solutions

The influence of various kinetic effects (e.g. Landau damping, diffusive and collisional dissipation, and finite Larmor radius terms) on the nonlinear evolution of finite amplitude Alfvenic wave trains in a finite-beta environment is systematically investigated using a novel, kinetic nonlinear Schrodinger (KNLS) equation. The dynamics of Alfven waves is sensitive to the sense of polarization as well as the angle of propagation with respect to the ambient magnetic field. Numerical solution for the case with Landau damping reveals the formation of dissipative structures, which are quasi-stationary, S-polarized directional (and rotational) discontinuities which self-organize from parallel propagating, linearly polarized waves. Parallel propagating circularly polarized packets evolve to a few circularly polarized Alfven harmonics on large scales. Stationary arc-polarized rotational discontinuities form from obliquely propagating waves. Collisional dissipation, even if weak, introduces enhanced wave damping when beta is very close to unity. Cyclotron motion effects on resonant particle interactions introduce cyclotron resonance into the nonlinear Alfven wave dynamics.Comment: 38 pages (including 23 figures and 1 table

Entropy in quantum chromodynamics

We review the role of zero-temperature entropy in several closely-related contexts in QCD. The first is entropy associated with disordered condensates, including $$. The second is vacuum entropy arising from QCD solitons such as center vortices, yielding confinement and chiral symmetry breaking. The third is entanglement entropy, which is entropy associated with a pure state, such as the QCD vacuum, when the state is partially unobserved and unknown. Typically, entanglement entropy of an unobserved three-volume scales not with the volume but with the area of its bounding surface. The fourth manifestation of entropy in QCD is the configurational entropy of light-particle world-lines and flux tubes; we argue that this entropy is critical for understanding how confinement produces chiral symmetry breakdown, as manifested by a dynamically-massive quark, a massless pion, and a $< \bar{q}q>$ condensate.Comment: 22 pages, 2 figures. Preprint version of invited review for Modern Physics Letters

Quenched Dislocation Enhanced Supersolid Ordering

I show using Landau theory that quenched dislocations can facilitate the supersolid (SS) to normal solid (NS) transition, making it possible for the transition to occur even if it does not in a dislocation-free crystal. I make detailed predictions for the dependence of the SS to NS transition temperature T_c(L), superfluid density %\rho_S(T, L), and specific heat C(T,L) on temperature T and dislocation spacing L, all of which can be tested against experiments. The results should also be applicable to an enormous variety of other systems, including, e.g., ferromagnets.Comment: 5 pages, 2 figure

The semantics of the lexeme «one»

У статті вивчається феномен заміни в англійській мові та проводиться комплексний аналіз слова-замінника «one». Визначено семантичні, граматичні та функціональні особливості цієї одиниці мови. Досліджено частоту вживання лексеми «one» в англійському художньому тексті. На прикладах з англійської художньої літератури проаналізовано функції, які виконує лексема «one», а саме функції: підмета, іменної частини присудка, додатка, означення. Зазначено, що денумератив «one» може використовуватися у реченні як іменник, займенник або як слово-замінник. Лексема «one» відіграє важливу роль у системі мови, де вона відрізняється великою частотою вживання та полі функціональністю. Лексема «one» має великий видільний потенціал та може виражати невизначеність. Автором доведено на конкретних прикладах, що слово-замінник «one» має свої граматичні, лексичні особливості та певні функції, а саме виявлено закономірності, які полягають у вживанні стосовно, як живих істот, так і неживих істот; виконуванні функції іменника у множині при використанні форми «ones». Автором підкреслено, що значення одиничності об’єктів є основним компонентом семантики лексеми «one». Об’єкти, які позначаються цією лексемою є протиставними до множинності. Доведено, що лексема «one» є однією з найважливіших мовних одиниць англійської мови. (The article deals with the studying of the phenomenon of substitution in the English language and the complex analysis of the substitution word «one». The semantic, grammatical and functional peculiarities of this speech unit are determined. The frequency of the use of the lexeme «one» in the English fictional text is studied. On the examples of English fiction literature such functions of the word «one» like subject, nominal part of the predicate, object, attribute have been determined. It has been noticed that as the notional word denumerative «one» has been used as a noun, pronoun and the substitution words. The lexeme «one» plays an important role in the language system and it is determined by a high frequency of using and polyfunctionality. Lexeme «one» has the great identifying potential and it may express the uncertainty. The author has proved on the examples that the substitution word «one» has its grammatical and lexical peculiarities and functions. It is used as well as towards living beings as inanimate objects; it may take the position of a noun in plural where the form «ones» is used The author has disclosed the aspect that the meaning of the singleness of the objects is the basis component of the semantics of other meanings of the lexeme «one». The objects that are determined by this lexeme are always opposed to multiplicity. It has been proved that the lexeme «one» is one of the most important speech units in the English language.