Liquid crystal defects and confinement in Yang-Mills theory

We show that in the Landau gauge of the SU(2) Yang-Mills theory the residual global symmetry supports existence of the topological vortices which resemble disclination defects in the nematic liquid crystals and the Alice (half-quantum) vortices in the superfluid heluim 3 in the A-phase. The theory also possesses half-integer and integer charged monopoles which are analogous to the point-like defects in the nematic crystal and in the liquid helium. We argue that the deconfinement phase transition in the Yang-Mills theory in the Landau gauge is associated with the proliferation of these vortices and/or monopoles. The disorder caused by these defects is suggested to be responsible for the confinement of quarks in the low-temperature phase.Comment: 9 pages, 5 figures, RevTeX styl

Lattice QCD Constraints on Hybrid and Quark Stars

A QCD-motivated dynamical-quasiparticle model with parameters adjusted to reproduce the lattice-QCD equation of state is extrapolated from region of high temperatures and moderate baryonic densities to the domain of high baryonic densities and zero temperature. The resulting equation of state matched with realistic hadronic equations of state predicts a phase transition into the quark phase at higher densities than those reachable in neutron star interiors. This excludes the possibility of the existence of hybrid (hadron-quark) stars. Pure quark stars are possible and have low masses, small radii and very high central densities. Similar results are obtained for a simple bag model with massive quarks, fitted to reproduce the same lattice results. Self-bound quark matter is also excluded within these models. Uncertainties in the present extrapolation re discussed. Comparison with standard bag models is made.Comment: 13 p., 8 figs., 7 tables, Version accepted by Phys. Rev.

On the Transport Properties of a Quark-Hadron Coulomb Lattice in the Cores of Neutron Stars

Already more that 40 years ago, it has been suggested that because of the enormous mass densities in the cores of neutron stars, the hadrons in the centers of neutron stars may undergo a phase transition to deconfined quark matter. In this picture, neutron stars could contain cores made of pure (up, down, strange) quark matter which are surrounded by a mixed phase of quarks and hadrons. More than that, because of the competition between the Coulomb and the surface energies associated with the positively charged regions of nuclear matter and negatively charged regions of quark matter, the mixed phase may develop geometrical structures, similarly to what is expected of the sub-nuclear liquid-gas phase transition. In this paper we restrict ourselves to considering the formation of rare phase blobs in the mixed quark-hadron phase. The influence of rare phase blobs on the thermal and transport properties of neutron star matter is investigated. The total specific heat, $c_V$, thermal conductivity, $\kappa$, and electron-blob Bremsstrahlung neutrino emissivities, $\epsilon_{\nu,\text{BR}}$, of quark-hybrid matter are computed and the results are compared with the associated thermal and transport properties of standard neutron star matter. Our results show that the contribution of rare phase blobs to the specific heat is negligibly small. This is different for the neutrino emissivity from electron-blob Bremsstrahlung scattering, which turns out to be of the same order of magnitude as the total contributions from other Bremsstrahlung processes for temperatures below about $10^8$ K.Comment: minor changes, accepted by Phys. Rev.

Plane torsion waves in quadratic gravitational theories

The definition of the Riemann-Cartan space of the plane wave type is given. The condition under which the torsion plane waves exist is found. It is expressed in the form of the restriction imposed on the coupling constants of the 10-parametric quadratic gravitational Lagrangian. In the mathematical appendix the formula for commutator of the variation operator and Hodge operator is proved. This formula is applied for the variational procedure when the gravitational field equations are obtained in terms of the exterior differential forms.Comment: 3 May 1998. - 11

Photon propagator, monopoles and the thermal phase transition in 3D compact QED

We investigate the gauge boson propagator in three dimensional compact Abelian gauge model in the Landau gauge at finite temperature. The presence of the monopole plasma in the confinement phase leads to appearance of an anomalous dimension in the momentum dependence of the propagator. The anomalous dimension as well as an appropriate ratio of photon wave function renormalization constants with and without monopoles are observed to be order parameters for the deconfinement phase transition. We discuss the relation between our results and the confining properties of the gluon propagator in non--Abelian gauge theories.Comment: 4 pages, 5 EPS figures, RevTeX 4, uses epsfig.sty; repaced to match version accepted for publication in Phys. Rev. Lett. (discussion on fits is extended

On the low fermionic eigenmode dominance in QCD on the lattice

We demonstrate the utility of a spectral approximation to fermion loop operators using low-lying eigenmodes of the hermitian Dirac-Wilson matrix, Q. The investigation is based on a total of 400 full QCD vacuum configurations, with two degenerate flavors of dynamical Wilson fermions at beta =5.6, at two different sea quark masses. The spectral approach is highly competitive for accessing both topological charge and disconnected diagrams, on large lattices and small quark masses. We propose suitable partial summation techniques that provide sufficient saturation for estimating Tr Q^{-1}, which is related to the topological charge. In the effective mass plot of the eta' meson we achieved a consistent early plateau formation, by ground state projecting the connected piece of its propagator.Comment: 15 pages, 25 figures, citations adde

On the Need for Phenomenological Theory of P-Vortices or Does Spaghetti Confinement Pattern Admit Condensed-Matter Analogies?

Usually the intuition from condensed-matter physics is used to provide ideas for possible confinement mechanisms in gauge theories. Today, with a clear but puzzling ``spaghetti'' confinement pattern, arising after a decade of lattice computer experiments, which implies formation of a fluctuating net of peculiar magnetic vortices rather than condensation of the homogeneously distributed magnetic monopoles, the time is coming to reverse the logic and search for similar patterns in condensed matter systems. The main thing to look for in a condensed matter setup is the simultaneous existence of narrow tubes ($P$-vortices or 1-branes) of direction-changing electric field and broader tubes (Abrikosov lines) of magnetic field, a pattern dual to the one, presumably underlying confinement in gluodynamics. As a possible place for this search we suggest systems with coexisting charge-density waves and superconductivity.Comment: 20 pages, 7 figures; to be published in ZhET

On the fermionic signature of the lattice monopoles

We consider fermions in the field of static monopole-like configurations in the Euclidean space-time. In all the cases considered there exists an infinite number of zero modes, labeled by frequency i\omega. The existence of such modes is a manifestation of instability of the vacuum in the presence of the monopoles and massless fermions. In the Minkowski space the corresponding phenomenon is well known and is a cornerstone of the theory of the magnetic catalysis. Moreover, the well known zero mode of Jackiw and Rebbi corresponds to the limiting case, \omega = 0. We provide arguments why the chiral condensate could be linked to the density of the monopoles in the infrared cluster. A mechanism which can naturally explain the equivalence of the critical temperatures for the deconfinement and chiral transitions, is proposed. We discuss possible implications for the phenomenology of the lattice monopoles.Comment: 8 pages, RevTeX 4. An extended version, to be published in the Physical Review

Phase Transitions In Compact Stars

We report on a three--month research project for undergraduate students about the mass-radius relation of compact stars. The equation of state used is constrained at low densities by well-established equations of state of the nuclear phase (the solid crust) and then extended to higher densities with a phenomenological, parametric approach. A first order phase transition from hadronic matter to a phase of higher density, assumed to be quark matter is studied in addition. The mass-radius relation is obtained by solving numerically the Tolman-Oppenheimer-Volkoff equation. We derive some conditions for the existence of a third family of compact stars on the form of the equation of state and its different global properties.Comment: 18 pages, 12 figures, refs. added, submitted to Eur. J. Phy

ОПРЕДЕЛЕНИЕ УРАНА В ВОДНЫХ РАСТВОРАХ МЕТОДОМ ВРЕМЯПРОЛЕТНОЙ МАСС-СПЕКТРОМЕТРИИ С ИМПУЛЬСНЫМ ТЛЕЮЩИМ РАЗРЯДОМ ПОСЛЕ ЕГО КОНЦЕНТРИРОВАНИЯ ОКИСЛЕННЫМИ УГЛЕРОДНЫМИ НАНОТРУБКАМИ

The pollution of the environment with uranium dictates the need to control the concentration of this element in natural waters to the permissible limits for the stability of the ecosystems and public health. In 2011, WHO set maximum permissible concentration of uranium in water to 0.03 ppm due to the strong toxicity and radioactivity of uranium in water. Therefore, the continuous monitoring of uranium content is an important task for the safety and health of the citizens. To determine the low uranium content in natural waters, the conservation of the studied solutions is necessary. However, this method of storage and transportation is not always simple. In the current paper, as a convenient method of concentrating uranium, preserving the sample and transporting it, we used the method of sorbing uranium on sorbents. Single-layer carbon nanotubes were used as sorbents. Their surfaces were modified using wet chemical oxidation and synthesis with Aerosil A-380 silica. Two schemes were considered for concentrating the uranium on the surface of the sorbent: individual carbon nanotubes and nanotubes modified with silica. The direct analysis was used to determine the content of uranium in the sorbent, namely, time-of-flight mass spectrometry with the pulsed glow discharge (GDMS). The most effective approach for the determination of uranium in water was the sorption of uranium on the tablet consisting of oxidized nanotubes modified with silica. The limit of detection in this case was 0.2 ppb.Keywords: mass-spectrometry, pulsed glow discharge, environment, direct analysis, uranium, carbon nanotubes  DOI: http://dx.doi.org/10.15826/analitika.2020.24.2.001Titova A.D1, Postnov V.N.1, Savinov S.S.1, Stolyarova N.V.2, Ivanenko N.B.2, Chuchina V.A.1, Gubal A.R.1, Ganeev A.A.1,21Saint-Petersburg State University (SPBU),Universitetskaya emb., 7/9, Saint-Petersburg, 199034, Russian Federation2Institute of Toxicology of Federal Medico-Biological Agency,ul. Bekhtereva, 1, Saint-Petersburg, 192019, Russian FederationЗагрязнение окружающей среды ураном диктует необходимость контроля концентрации этого элемента в природных водах до допустимых пределов, что необходимо для стабильности экосистем и здоровья населения. Из-за сильной токсичности и радиоактивности в 2011 году ВОЗ установила предельно допустимую концентрацию урана в воде – 0.03 ppm. При транспортировке проб природной воды с низким содержанием урана (на уровне ПДК) их консервируют. В качестве удобного способа транспортировки пробы и одновременного концентрирования урана в данной работе предложено сорбировать его на однослойных углеродных нанотрубках. Поверхность углеродных нанотрубок предварительно модифицировали химическим окислением и обрабатывали кремнеземом аэросил А-380. Рассматривали два варианта концентрирования урана на поверхность сорбента: индивидуальные и модифицированные кремнеземом углеродные нанотрубки. Для анализа использовали прямой метод определения содержания урана в сорбенте − времяпролетную масс-спектрометрию с импульсным тлеющим разрядом (GD-MS). Показано, что наиболее эффективным подходом для определения урана в воде стала сорбция урана на таблетку, состоящую из модифицированных кремнеземом окисленных нанотрубок. Предел обнаружения при этом составил 0.2 ppb.Ключевые слова: масс-спектрометрия, импульсный тлеющий разряд, окружающая среда, прямой анализ, уран, углеродные нанотрубкиDOI: http://dx.doi.org/10.15826/analitika.2020.24.2.00