Magnetic permeability of near-critical 3d abelian Higgs model and duality

The three-dimensional abelian Higgs model has been argued to be dual to a scalar field theory with a global U(1) symmetry. We show that this duality, together with the scaling and universality hypotheses, implies a scaling law for the magnetic permeablity chi_m near the line of second order phase transition: chi_m ~ t^nu, where t is the deviation from the critical line and nu ~ 0.67 is a critical exponent of the O(2) universality class. We also show that exactly on the critical lines, the dependence of magnetic induction on external magnetic field is quadratic, with a proportionality coefficient depending only on the gauge coupling. These predictions provide a way for testing the duality conjecture on the lattice in the Coulomb phase and at the phase transion.Comment: 11 pages; updated references and small changes, published versio

The impact of QCD plasma instabilities on bottom-up thermalization

QCD plasma instabilities, caused by an anisotropic momentum distributions of the particles in the plasma, are likely to play an important role in thermalization in heavy ion collisions. We consider plasmas with two different components of particles, one strongly anisotropic and one isotropic or nearly isotropic. The isotropic component does not eliminate instabilities but it decreases their growth rates. We investigate the impact of plasma instabilities on the first stage of the ``bottom-up'' thermalization scenario in which such a two-component plasma emerges, and find that even in the case of non-abelian saturation instabilities qualitatively change the bottom-up picture.Comment: 12 pages, latex, one typo corrected, several minor changes in the abstract and the text, to appear in JHE

On the Chiral Phase Transition in the Linear Sigma Model

The Cornwall-Jackiw-Tomboulis (CJT) effective action for composite operators at finite temperature is used to investigate the chiral phase transition within the framework of the linear sigma model as the low-energy effective model of quantum chromodynamics (QCD). A new renormalization prescription for the CJT effective action in the Hartree-Fock (HF) approximation is proposed. A numerical study, which incorporates both thermal and quantum effect, shows that in this approximation the phase transition is of first order. However, taking into account the higher-loop diagrams contribution the order of phase transition is unchanged.Comment: 12 pages, 4 figure

Thermal production of ultrarelativistic right-handed neutrinos: Complete leading-order results

The thermal production of relativistic right-handed Majorana neutrinos is of importance for models of thermal leptogenesis in the early Universe. Right-handed neutrinos can be produced both by 1 2 decay or inverse decay and by 2 -> 2 scattering processes. In a previous publication, we have studied the production via 1 2 (inverse) decay processes. There we have shown that multiple scattering mediated by soft gauge boson exchange also contributes to the production rate at leading order, and gives a strong enhancement. Here we complete the leading order calculation by adding 2 -> 2 scattering processes involving either electroweak gauge bosons or third-generation quarks. We find that processes with gauge interactions give the most important contributions. We also obtain a new sum rule for the Hard Thermal Loop resummed fermion propagator.Comment: 27 pages, 7 figures. Error in the matrix element for the (subdominant) subprocess with s-channel fermion exchange corrected. This changes the corresponding phase space integral and the constant c_V. Numerically it increases the total 2 -> 2 rate by about 2 percent and the complete rate by about 1 percent. The main results and conclusions are unaffecte

The stochastic gravitational wave background from turbulence and magnetic fields generated by a first-order phase transition

We analytically derive the spectrum of gravitational waves due to magneto-hydrodynamical turbulence generated by bubble collisions in a first-order phase transition. In contrast to previous studies, we take into account the fact that turbulence and magnetic fields act as sources of gravitational waves for many Hubble times after the phase transition is completed. This modifies the gravitational wave spectrum at large scales. We also model the initial stirring phase preceding the Kolmogorov cascade, while earlier works assume that the Kolmogorov spectrum sets in instantaneously. The continuity in time of the source is relevant for a correct determination of the peak position of the gravitational wave spectrum. We discuss how the results depend on assumptions about the unequal-time correlation of the source and motivate a realistic choice for it. Our treatment gives a similar peak frequency as previous analyses but the amplitude of the signal is reduced due to the use of a more realistic power spectrum for the magneto-hydrodynamical turbulence. For a strongly first-order electroweak phase transition, the signal is observable with the space interferometer LISA.Comment: 46 pages, 17 figures. Replaced with revised version accepted for publication in JCA

Comparative Study between the Overall Production Time of Digitally Versus Conventionally Produced Indirect Orthodontic Bonding Trays

Objective:The purpose of this study was to compare the production time for indirect digitally and laboratory-produced orthodontic bonding trays.Methods:Orthodontic study casts were used in this study (n=40). The specimens were equally and randomly divided. In the digitally produced indirect bonding tray (DIBT) group (n=20), the brackets were set virtually using the Orthoanalyzer program (3Shape, Copenhagen, Denmark) to produce an indirect bonding tray that was virtually designed and 3D printed using VarseoWax® Splint material with a Varseo S 3D printer (Bego, Bremen, Germany). In the laboratory-produced indirect bonding tray (LIBT) group, the brackets were adhesively bonded to the study casts in the dental laboratory (Danube Private University, Krems, Austria), and a transfer bonding silicone tray was manufactured.Results:The t-test results showed a significant difference between the passive time during the production of DIBTs (153.8±32.8 min) and LIBTs (7 min). However, the active production time was 13.6±0.8 min for DIBTs and 17.7±1.9 min for LIBTs. Every individual process step in both groups was measured in minutes, and statistical analysis was performed.Conclusion:The total production time, including active working and passive non-working time, was higher for DIBTs than for LIBTs. However, the actual active production time for DIBTs was shorter than that for LIBTs. Within the study limitations, the digital planning and production of indirect orthodontic trays can be considered a time-efficient production method

Three Dimensional N=2 Supersymmetry on the Lattice

We show how 3-dimensional, N=2 supersymmetric theories, including super QCD with matter fields, can be put on the lattice with existing techniques, in a way which will recover supersymmetry in the small lattice spacing limit. Residual supersymmetry breaking effects are suppressed in the small lattice spacing limit by at least one power of the lattice spacing a.Comment: 21 pages, 2 figures, typo corrected, reference adde

Thermal production of relativistic Majorana neutrinos: Strong enhancement by multiple soft scattering

The production rate of heavy Majorana neutrinos is relevant for models of thermal leptogenesis in the early Universe. In the high temperature limit the production can proceed via the 1 2 (inverse) decays which are allowed by the thermal masses. We consider new production mechanisms which are obtained by including additional soft gauge interactions with the plasma. We show that an arbitrary number of such interactions gives leading order contributions, and we sum all of them. The rate turns out to be smooth in the region where the 1 2 processes are kinematically forbidden. At higher temperature it is enhanced by a factor 3 compared to the 1 2 rate.Comment: 26 pages, 8 figures; added references, added comments on 2 to 2 scattering processes, improved appearance of fig. 8, corrected typos; matches published versio

Quasiparticle Description of the QCD Plasma, Comparison with Lattice Results at Finite T and Mu

We compare our 2+1 flavor, staggered QCD lattice results with a quasiparticle picture. We determine the pressure, the energy density, the baryon density, the speed of sound and the thermal masses as a function of T and $\mu_B$. For the available thermodynamic quantities the difference is a few percent between the results of the two approaches. We also give the phase diagram on the $\mu_B$--T plane and estimate the critical chemical potential at vanishing temperature.Comment: 13 pages, 10 figure