Initial Conditions for Supersymmetric Inflation

We perform a numerical investigation of the fields evolution in the supersymmetric inflationary model based on radiative corrections. Supergravity corrections are also included. We find that, out of all the examined initial data, only about 10% give an adequate amount of inflation and can be considered as ''natural''. Moreover, these successful initial conditions appear scattered and more or less isolated.Comment: 15 pages RevTeX 4 eps figure

Copurification of actin and desmin from chicken smooth muscle and their copolymerization in vitro to intermediate filaments

Desmin is a 50,000-mol wt protein that is enriched along with 100-A filaments in chicken gizzard that has been extracted with 1 M KI. Although 1 M KI removes most of the actin from gizzard, a small fraction of this protein remains persistently insoluble, along with desmin. The solubility properties of this actin are the same as for desmin: they are both insoluble in high salt concentrations, but are solubilized at low pH or by agents that dissociate hydrophobic bonds. Desmin may be purified by repeated cycles of solubilization by 1 M acetic acid and subsequent precipitation by neutralization to pH 4. During this process, a constant nonstoichiometric ratio of actin to desmin is attained. Gel filtration on Ultrogel AcA34 in the presence of 0.5% Sarkosyl NL-97 reveals nonmonomeric fractions of actin and desmin that comigrate through the column. Gel filtration on Bio-Gel P300 in the presence of 1 M acetic acid reveals that the majority of desmin is monomeric under these conditions. A small fraction of desmin and all of the actin elute with the excluded volume. When the acetic acid is removed from actin-desmin solutions by dialysis, a gel forms that is composed of filaments with diameters of 120-140 A. These filaments react uniformly with both anti-actin and anti-desmin antiserum. These results suggest that desmin is the major subunit of the muscle 100-A filaments and that it may form nonstoichiometric complexes with actin

Bulk and surface magnetoinductive breathers in binary metamaterials

We study theoretically the existence of bulk and surface discrete breathers in a one-dimensional magnetic metamaterial comprised of a periodic binary array of split-ring resonators. The two types of resonators differ in the size of their slits and this leads to different resonant frequencies. In the framework of the rotating-wave approximation (RWA) we construct several types of breather excitations for both the energy-conserved and the dissipative-driven systems by continuation of trivial breather solutions from the anticontinuous limit to finite couplings. Numerically-exact computations that integrate the full model equations confirm the quality of the RWA results. Moreover, it is demonstrated that discrete breathers can spontaneously appear in the dissipative-driven system as a results of a fundamental instability.Comment: 10 pages, 16 figure

Strongly interacting one-dimensional bosons in arbitrary-strength optical lattices: from Bose-Hubbard to sine-Gordon and beyond

We analyze interacting one-dimensional bosons in the continuum, subject to a periodic sinusoidal potential of arbitrary depth. Variation of the lattice depth tunes the system from the Bose-Hubbard limit for deep lattices, through the sine-Gordon regime of weak lattices, to the complete absence of a lattice. Using the Bose-Fermi mapping between strongly interacting bosons and weakly interacting fermions, we derive the phase diagram in the parameter space of lattice depth and chemical potential. This extends previous knowledge from tight-binding (Bose-Hubbard) studies in a new direction which is important because the lattice depth is a readily adjustable experimental parameter. Several other results (equations of state, energy gaps, profiles in harmonic trap) are presented as corollaries to the physics contained in this phase diagram. Generically, both incompressible (gapped) and compressible phases coexist in a trap; this has implications for experimental measurements

Evidence for a Phosphorylated Form of Calmodulin in Chicken Brain and Muscle

Phosphocalmodulin (PCaM) was identified after analysis of calmodulin (CaM) preparations by two-dimensional gel electrophoresis by using a modified ampholyte system to resolve very acidic proteins. The analysis of CaM prepared by the conventional procedure based upon its heat resistance and acidity as well as the analysis of whole urea extracts from brain showed that PCaM was a major component in this tissue. PCaM was 1 pH unit more acidic than CaM, and its electrophoretic mobility, unlike CaM, was not changed by either calcium or ethylene glycol-bis(β-aminoethyl ether)-N,N-tetraacetic acid. In urea extracts of brain prepared in buffers containing phosphate and sodium fluoride, PCaM was as prominent as CaM; it was partially converted into CaM after elution from the gel and reelectrophoresis. Amino acid analysis of PCaM and CaM purified by two-dimensional gel electrophoresis showed the same composition for the two proteins, including their trimethyllysine content. Incorporation of (^32)P occurred exclusively into the acidic variant when brain slices were incubated with (H_3)(^32(PO_4)); amino acid analysis showed that the phosphate was bound to serine residues. CaM was found also to be phosphorylated in vitro by a phosphorylase kinase preparation from skeletal muscle

Fine tuning of the initial conditions for hybrid inflation

We study the evolution of regions of space with various initial field values for a simple theory that can support hybrid inflation. Only very narrow domains within the range of initial field values below the Planck scale lead to the onset of inflation. This implies a severe fine tuning for the initial configuration that will produce inflation.Comment: 11 pages, LaTeX, 8 figures in eps forma

Field Evolution leading to hybrid inflation

In general the onset of hybrid inflation requires an extremely homogeneous field configuration at the end of Planck era. The field \phi orthogonal to the inflaton \sigma must be zero with high accuracy over the range exceeding the initial horizon size \sim m_{Pl}^{-1} by about two orders of magnitude. We consider a supersymmetric model that permits the decay of the oscillating field \phi into light particles. We study the field evolution and find that the requirement of the extreme homogeneity can be relaxed. However, the field \phi must still be smaller than the inflaton by a factor of order 1 over a region far exceeding the initial horizon size.Comment: Latex, 9 pages, 3 figure

Particle Physics Approach to Dark Matter

We review the main proposals of particle physics for the composition of the cold dark matter in the universe. Strong axion contribution to cold dark matter is not favored if the Peccei-Quinn field emerges with non-zero value at the end of inflation and the inflationary scale is superheavy since, under these circumstances, it leads to unacceptably large isocurvature perturbations. The lightest neutralino is the most popular candidate constituent of cold dark matter. Its relic abundance in the constrained minimal supersymmetric standard model can be reduced to acceptable values by pole annihilation of neutralinos or neutralino-stau coannihilation. Axinos can also contribute to cold dark matter provided that the reheat temperature is adequately low. Gravitinos can constitute the cold dark matter only in limited regions of the parameter space. We present a supersymmetric grand unified model leading to violation of Yukawa unification and, thus, allowing an acceptable b-quark mass within the constrained minimal supersymmetric standard model with mu>0. The model possesses a wide range of parameters consistent with the data on the cold dark matter abundance as well as other phenomenological constraints. Also, it leads to a new version of shifted hybrid inflation.Comment: 32 pages including 6 figures, uses svmult.cls, some clarifications added, lectures given at the Third Aegean Summer School "The Invisible Universe: Dark Matter and Dark Energy", 26 September-1 October 2005, Karfas, Island of Chios, Greece (to appear in the proceedings