Abstract:
We study collective excitations in systems described by chiral kinetic theory in external magnetic field. We consider high-temperature weak-coupling plasma, as well as high-density Landau Fermi liquid with interaction not restricted to be weak. We show that chiral magnetic wave (CMW) emerges in hydrodynamic regime (at frequencies smaller than collision relaxation rate) and the CMW velocity is determined by thermodynamic properties only. We find that in a plasma of opposite chiralities, at frequencies smaller than the chirality-flipping rate, the CMW excitation turns into a vector-like diffusion mode. In the interacting Fermi liquid, the CMW turns into the Landau zero sound mode in the high-frequency collisionless regime.

Abstract:
We develop a quantum kinetic theory of the chiral condensate and meson quasi-particle excitations using the O(N) linear sigma model which describe the chiral phase transition both in and out of equilibrium in a unified way. A mean field approximation is formulated in the presence of mesonic quasi-particle excitations which are described by generalized Wigner functions. It is shown that in equilibrium our kinetic equations reduce to the gap equations which determine the equilibrium condensate amplitude and the effective masses of the quasi-particle excitations, while linearization of transport equations, near such equilibrium, determine the dispersion relations of the collective mesonic excitations at finite temperatures. Although all mass parameters for the meson excitations become at finite temperature, apparently violating the Goldstone theorem, the missing Nambu-Goldstone modes are retrieved in the collective excitations of the system as three degenerate phonon-like modes in the symmetry-broken phase. We show that the temperature dependence of the pole masses of the collective pion excitations has non-analytic kink behavior at the threshold of the quasi-particle excitations in the presence of explicit symmetry breaking interaction.

Abstract:
We develop a quantum kinetic theory of the chiral condensate and meson quasi-particle excitations using the O(N) linear sigma model which describe the chiral phase transition both in and out of equilibrium in a unified way. A mean field approximation is formulated in the presence of mesonic quasi-particle excitations which are described by generalized Wigner functions. It is shown that in equilibrium our kinetic equations reduce to the gap equations which determine the equilibrium condensate amplitude and the effective masses of the quasi-particle excitations, while linearization of transport equations, near such equilibrium, determine the dispersion relations of the collective mesonic excitations at finite temperatures. Although all mass parameters for the meson excitations become at finite temperature, apparently violating the Goldstone theorem, the missing Nambu-Goldstone modes are retrieved in the collective excitations of the system as three degenerate phonon-like modes in the symmetry-broken phase. We show that the temperature dependence of the pole masses of the collective pion excitations has non-analytic kink behavior at the threshold of the quasi-particle excitations in the presence of explicit symmetry breaking interaction.

Abstract:
According to the large $N_C$ limit of QCD baryons are considered as soliton solutions in effective mesons theories. While the classical solitons dwell in the isospin subgroup of flavor SU(3) hyperon states are generated by canonical quantization of the collective coordinates which describe the flavor orientation of the soliton. The resulting Hamiltonian is diagonalized exactly allowing one to discuss the dependence of various baryon properties on flavor symmetry breaking. In particular axial charges, baryon magnetic moments and radiative decay widths are considered.

Abstract:
The perturbative calculation of the lifetime of fermion excitations in a QED plasma at high temperature is plagued with infrared divergences which are not eliminated by the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of longwavelength, quasistatic, magnetic photons, which are not screened by plasma effects. The leading divergences can be resummed in a non-perturbative treatement based on a generalization of the Bloch-Nordsieck model at finite temperature. The resulting expression of the fermion propagator is free of infrared problems, and exhibits a {\it non-exponential} damping at large times: $S_R(t)\sim \exp\{-\alpha T t \ln\omega_pt\}$, where $\omega_p=eT/3$ is the plasma frequency and $\alpha=e^2/4\pi$.

Abstract:
In chiral soliton models for baryons the computation of hadronic decay widths of baryon resonances is a long standing problem. For the three flavor Skyrme model I present a solution to this problem that satisfies large--$N_C$ consistency conditions. As an application I focus on the hadronic decay of the $\Theta$ and $\Theta^*$ pentaquarks.

Abstract:
In this talk I discuss collective excitations that carry fermion quantum numbers. Such excitations occur in the quark-gluon plasma and can also be produced in cold atom systems under special conditions.

Abstract:
We calculate the frequencies and damping rates of the low-lying collective modes of a Bose-Einstein condensed gas at nonzero temperature. We use a complex nonlinear Schr\"odinger equation to determine the dynamics of the condensate atoms, and couple it to a Boltzmann equation for the noncondensate atoms. In this manner we take into account both collisions between noncondensate-noncondensate and condensate-noncondensate atoms. We solve the linear response of these equations, using a time-dependent gaussian trial function for the condensate wave function and a truncated power expansion for the deviation function of the thermal cloud. As a result, our calculation turns out to be characterized by two dimensionless parameters proportional to the noncondensate-noncondensate and condensate-noncondensate mean collision times. We find in general quite good agreement with experiment, both for the frequencies and damping of the collective modes.

Abstract:
We study the collective modes in relativistic electromagnetic or quark-gluon plasmas with an asymmetry between left- and right-handed chiral fermions, based on the recently formulated kinetic theory with Berry curvature corrections. We find that there exists an unstable mode, signaling the presence of a plasma instability. We argue the fate of this "chiral plasma instability" including the effect of collisions, and briefly discuss its relevance in heavy ion collisions and compact stars.

Abstract:
We study the collective modes in relativistic electromagnetic or quark-gluon plasmas with an asymmetry between left- and right-handed chiral fermions, based on the recently formulated kinetic theory with Berry curvature corrections. We find that there exists an unstable mode, signaling the presence of a plasma instability. We argue the fate of this "chiral plasma instability" including the effect of collisions, and briefly discuss its relevance in heavy ion collisions and compact stars.