Three-body calculation of the 1s1s level shift in kaonic deuterium

The first calculation of kaonic deuterium $1s$ level shift using Faddeev-type equations was performed. The obtained results were compared with commonly used approximate approaches.Comment: The version accepted in Phys. Lett.

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

Deep-water organic-mineral sediments of the black sea as the object of mining and dewatering

The results of laboratory investigations of grain-size, physical, mechanical and rheological properties of the deep-sea organic-mineral sediments sampled from the depth of 1,920 – 2,150 m at the polygon “Sapropels” in the Black Sea are given. The results obtained are analyzed. The class of particle size distribution and soil category in difficulty of developing for this type of sediments are established.Представлено результати лабораторних досліджень гранулометричного складу, фізикомеханічних та реологічних властивостей глибоководних органо-мінеральних відкладень Чорного моря, відібраних з глибини 1920 – 2150 м на полігоні «Сапропелі». Проведено аналіз отриманих результатів. Визначено клас даного типу відкладень по гранулометричному складу і категорія ґрунту по важкості розробки.Приведены результаты лабораторных исследований гранулометрического состава, физикомеханических и реологических свойств глубоководных органо-минеральных осадков Черного моря, отобранных с глубины 1920 – 2150 м на полигоне «Сапропели». Проведен анализ полученных результатов. Определен класс данного типа отложений по гранулометрическому составу и категория грунта по трудности разработки

Phase transformation B1 to B2 in TiC, TiN, ZrC and ZrN under pressure

Phase stability of various phases of MX (M = Ti, Zr; X = C, N) at equilibrium and under pressure is examined based on first-principles calculations of the electronic and phonon structures. The results reveal that all B1 (NaCl-type) MX structures undergo a phase transition to the B2-structures under high pressure in agreement with the previous total-energy calculations. The B1-MX structures are dynamically stable under very high pressure (210-570 GPa). The pressure-induced B2 (CsCl-type) MC phases are dynamically unstable even at high pressures, and TiN and ZrN are found to crystallize with the B2-structure only at pressures above 55 GPa. The first-order B1-to-B2 phase transition in these nitrides is not related to the softening of phonon modes, and the dynamical instability of B2-MX is associated with a high density of states at the Fermi level.Comment: 9 pages, 4 figure

Dislocation-induced superfluidity in a model supersolid

Motivated by recent experiments on the supersolid behavior of $^4$He, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. Using Landau theory, we couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.Comment: 10 pages, 6 figure