Table of contents

We extend the quark model loop for π → eνγ decay to the chiral quark loop (including the effect of scalar mesons), thus reducing the value of γ ≡ F_A/F_V from 1 to 2/3 for the SU(2) linear σ-model. Also, we extend vector-meson dominance to axial-meson dominance for π → eνγ, thus obtaining γ ≃ +1/2. Both results are in line with the measured value γ = 0.51 ± 0.32 or |γ| = 0.45 ± 0.08.

Magnetically induced laser cooling to temperatures close to the recoil limit is investigated in one dimension. For a metastable neon beam, we present high-precision measurements investigating the actual temperature limit in this cooling process. Using time-of-flight techniques to reduce the effect of the longitudinal velocity spread, we observe cooling at small magnetic field toward ν = 0 with an r.m.s. width of the distribution of 5.4 cm/s, well below the Doppler limit. At a larger magnetic field (0.4 Gauss) the velocity-selective resonances are extremely sharp. Here we find the r.m.s. width of the distribution to be 3.4 cm/s, only 1.1 times the recoil speed ℏk/M, corresponding to a temperature T = 2.7 μK.

The effect of connection between giant wormlike micelles is studied. We calculate the diffusion rate, which is increased by the sliding connections. We calculate the viscosity which is weakly reduced by the connections in the case of scission-recombination reactions.

The temperature dependence of the growth coefficient in the angular vicinity of the basal [0001] facet of hcp ⁴He crystals has been measured in the temperature range from 0.35 K to 0.45 K. Contrary to theoretical predictions this dependence turned out to be much stronger for vicinal surfaces than for nonvicinal orientations. For vicinal surfaces experimental data can be approximated by both K ∝ T⁻⁵ and K ∝ exp[ε/T] dependences, where ε = 1.9 K.

We study equilibrium phase separation of immiscible diblock copolymer chains, A-B and B-A, end-grafted to the interior surface of cylinders or spheres. We show that with the grafting surface curving moderately, the microphase separation pattern is qualitatively different from that for a flat surface. When h/R > ρ_c (h is the height of the polymer layer and R is the radius of the cylinder or sphere), the chains tend to "layer" with the free ends segregating radially. The local composition then forms a three-layer pattern: A-B-A or B-A-B. The values of ρ_c are found to be 0.32 and 0.13 for cylinder and sphere, respectively. Analogous layering occurs in homopolymer blends grafted on spherical surface when h/R > 0.44.

The confinement of liquid crystalline polymers dissolved in a nematic solvent is analysed using a mean-field theory. For homeotropic anchoring the confinement triggers a tilting phase transition. The transition is reminiscent of the Frederiks transition, however it may be either first or second order.

Using quantum Monte Carlo and finite-size scaling for the Hubbard model, we find evidence of a zero-temperature transition between the nonmagnetic semi-metal and an antiferromagnetic insulator in the 2D honeycomb lattice for a nontrivial value of U/t = 4.5 ± 0.5. The corresponding transition in Hartree-Fock mean field is at U/t = 2.23, which indicates the importance of quantum fluctuations. This represents the first example of Mott-Hubbard transition in a 2D bipartite lattice. Similar transitions are predicted for special lattices in higher dimensions, in particular for the 3D diamond lattice.

Non-Abelian (NA) version of the hierarchical FQH states is proposed. The topological order (TO) in these states is shown to be described by some U(N) coset Chern-Simons (CS) theory. For this all the necessary information about the TO can be found in the theory of the edge excitations (EE). This theory is described in terms of the corresponding gauged Wess-Zumino-Witten model related to the bulk theory through the Witten isomorfism.

The magnetic moment of Cr overlayers deposited on Fe(100) was investigated by spin-resolved core level photoemission. Data for the Cr 3p level show that a monolayer of Cr is ferromagnetically ordered with a magnetic moment oriented antiparallel to the Fe moments. The results suggest that at room temperature the moment of a Cr monolayer on Fe is of the order of 0.5 to 1μ_B per Cr atom.

Multilayered amorphous ribbons were produced by electrolytical deposition. They have exceptional magnetoelastic properties which enhance the amplitude of longitudinal magnetoacoustic waves travelling in the samples, also in comparison with similar-size ribbons of conventional metallic glass obtained by rapid quenching from the melt.

Mössbauer absorption and diffraction spectra were studied on a nearly perfect ⁵⁷FeBO₃ single-crystal platelet exposed to a magnetic r.f. field with a frequency of about 1 MHz. In the Mössbauer absorption spectra the r.f. field causes a strong broadening of the absorption lines which is mainly due to lattice vibrations polarized along the surface of the platelet. These vibrations have a strong influence on the pure nuclear Bragg reflection ⁵⁷FeBO₃(333), where they produce a Gaussian broadening of the four lines of the Mössbauer diffraction spectrum to such an extent that the spectrum forms a region of high reflectivity about 100 ÷ 200 natural linewidths wide.

The energy condensation in a Fröhlich vibration system depends on the energy transfer between vibration modes in interaction with a heat bath. The great rate of energy transfer is conditioned by strong coupling with a heat bath but the energy condensed in the system is small as follows from computer simulation. The energy condensation in the higher-frequency modes is reduced by strong coupling with a heat bath; for much stronger coupling the energy condensed in the lowest-frequency mode is decreased too. Protein phosphorylation may cause strong coupling with the heat bath due to the Coulomb forces. The effect on the coherent-states excitations and its role in the cancer transformation of cells is discussed.