We study the effect of non-relativistic, thermal matter in the jets of active galaxies (AGN) on the low-frequency non-thermal emission and the variability thereof. In matter-dominated jets, sizable quantities of gas should exist, in particular in the compression zones near the collision fronts that are an implicit ingredient of Fermi-type particle acceleration scenarios. Non-relativistic therma...

We compare the position of an ordering transition in a metal to that in a superconductor. For the spin density wave (SDW) transition, we find that the quantum critical point shifts by order |∆|, where ∆ is pairing amplitude, so that the region of SDW order is smaller in the superconductor than in the metal. This shift is larger than the ∼ |∆| shift predicted by theories of competing orders whic...

We test a non-equilibrium approach to study the behaviour of a Bose–Fermi mixture of alkali atoms in the presence of a Feshbach resonance between bosons and fermions. To this end we derive the Hartree–Fock–Bogoliubov (HFB) equations of motion for the interacting system. This approach has proven very successful in the study of resonant systems composed of Bose particles and Fermi particles. Howe...

We present a numerical model for electron acceleration and radiation inside the body of an extragalactic jet. We model the jet environment as a turbulent medium generating non-linear structures (eddies and/or shocks) through a cascading process. These structures act like in-situ accelerators for the electrons that are initially injected from the central engine. Two types of acceleration process...

We study the non-singlet sectors of Matrix Quantum Mechanics in application to two-dimensional string theory. We use the chiral formalism, which operates directly with incoming and outgoing asymptotic states, related by a scattering operator. We argue that a general non-singlet scattering amplitude decomposes into scattering amplitudes in the adjoint. In the adjoint representation, we express t...

Gamma-ray bursts (GRBs) were detected for the first time in 1967 in the range 0.1-1MeV [1] by US satellites Vela intended for monitoring of nuclear explosions in the atmosphere of the Earth. As was shown later these bursts had an astrophysical origin and did not connect to any processes at the Earth. Three possible locations of GRBs were assumed: the solar system, our Galaxy and sources at cosm...

Any smooth spatial disturbance of a degenerate Fermi gas inevitably becomes sharp. This phenomenon, called the gradient catastrophe, causes the breakdown of a Fermi sea to multiconnected components characterized by multiple Fermi points. We argue that the gradient catastrophe can be probed through a Fermi-edge singularity measurement. In the regime of the gradient catastrophe the Fermi-edge sin...

For systems of electrons that can exchange energy and particles with a large medium, the celebrated Fermi Dirac (FD) distribution provides the probability for an electron to occupy a given energy level after the total energy of the system has been increased. This powerful tool derives from the laws of statistical mechanics (see, e.g., Landau and Lifchitz [3]). But this result does not apply to ...

We review current theoretical ideas on pulsar winds and their surrounding nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the striped wind, together with models of magnetic dissipation are discussed. It is shown that the observational signature of this dissipation is likely to be point-like, rather than extended, and that pulsed emission may be produced. The possible...