Resonant Relaxation in Electroweak Baryogenesis

We compute the leading, chiral charge-changing relaxation term in the quantum transport equations that govern electroweak baryogenesis using the closed time path formulation of non-equilibrium quantum field theory. We show that the relaxation transport coefficients may be resonantly enhanced under appropriate conditions on electroweak model parameters and that such enhancements can mitigate the impact of similar enhancements in the CP-violating source terms. We also develop a power counting in the time and energy scales entering electroweak baryogenesis and include effects through second order in ratios $\epsilon$ of the small and large scales. We illustrate the implications of the resonantly enhanced ${\cal O}(\epsilon^2)$ terms using the Minimal Supersymmetric Standard Model, focusing on the interplay between the requirements of baryogenesis and constraints obtained from collider studies, precision electroweak data, and electric dipole moment searches.Comment: 30 pages plus appendices, 7 figure

Field quantization and squeezed states generation in resonators with time-dependent parameters

The problem of electromagnetic field quantization is usually considered in textbooks under the assumption that the field occupies some empty box. The case when a nonuniform time-dependent dielectric medium is confined in some space region with time-dependent boundaries is studied. The basis of the subsequent consideration is the system of Maxwell's equations in linear passive time-dependent dielectric and magnetic medium without sources

Detection of Spiral photons in Quantum Optics

We show that a new type of photon detector, sensitive to the gradients of electromagnetic fields, should be a useful tool to characterize the quantum properties of spatially-dependent optical fields. As a simple detector of such a kind, we propose using magnetic dipole or electric quadrupole transitions in atoms or molecules and apply it to the detection of spiral photons in Laguerre-Gauss (LG) beams. We show that LG beams are not true hollow beams, due to the presence of magnetic fields and gradients of electric fields on beam axis. This approach paves the way to an analysis at the quantum level of the spatial structure and angular momentum properties of singular light beams.Comment: 5 pages, 4 figure

Multiexcitons confined within a sub-excitonic volume: Spectroscopic and dynamical signatures of neutral and charged biexcitons in ultrasmall semiconductor nanocrystals

The use of ultrafast gating techniques allows us to resolve both spectrally and temporally the emission from short-lived neutral and negatively charged biexcitons in ultrasmall (sub-10 nm) CdSe nanocrystals (nanocrystal quantum dots). Because of forced overlap of electronic wave functions and reduced dielectric screening, these states are characterized by giant interaction energies of tens (neutral biexcitons) to hundreds (charged biexcitons) of meV. Both types of biexcitons show extremely short lifetimes (from sub-100 picoseconds to sub-picosecond time scales) that rapidly shorten with decreasing nanocrystal size. These ultrafast relaxation dynamics are explained in terms of highly efficient nonradiative Auger recombination.Comment: 5 pages, 4 figures, to be published in Phys. Rev.

Quadrupole transitions near interface: general theory and application to atom inside a planar cavity

Quadrupole radiation of an atom in an arbitrary environment is investigated within classical as well as quantum electrodynamical approaches. Analytical expressions for decay rates are obtained in terms of Green function of Maxwell equations. The equivalence of both approaches is shown. General expressions are applied to analyze the quadrupole decay rate of an atom placed between two half spaces with arbitrary dielectric constant. It is shown that in the case when the atom is close to the surface, the total decay rate is inversely proportional to the fifth power of distance between an atom and a plane interface.Comment: 18 pages, 7 figure