Effects of weak and electromagnetic interactions in bound systems

Abstract

This thesis investigates the influence of various external fields on the bound states of quantum systems. This includes the shifts induced by static and dynamic electric fields and their gradients on atomic levels, symmetry violating nuclear potentials on atomic and molecular electronic structure, weak and strong interactions on the Higgs induced bound states of heavy fourth generation quarkonium. Static and dynamic electric fields are responsible for the largest systematic shifts in the current generation of atomic clocks. We propose a new method for canceling out the quadrupole shift and show that the black body radiation shift in atomic clocks is greatly suppressed if the clock transition occurs between states of the same configuration. We also consider the possibility of using dynamic Stark shift of a single known transition in highly charged ion to find excited states that give resonant contributions to dynamic scalar polarizability. The effects of P, T-odd nuclear multipole moments in atoms, ions, and molecules are considered. We show that Schiff theorem about screening of external electric field on the nucleus can be extended to ions and molecules. Finally we extend our analysis to the problems of particle physics. Hypothetical fourth generation quarks are expected to be bound via a Higgs field that can overcome strong repulsion even in color-octet state. The presented calculations show that the energy of a bound color-octet state is at least an order of magnitude greater than the total decay width. These quarks, bound together via Higgs mechanism, can bind the lighter quark by strong interaction, forming together colorless, therefore observable particle. Such particle has a structure similar to Deuterium atom (nucleus consists of two heavy quarks and a light quark or gluon that compensates net color at large distances) and may be observed during the quarkonium synthesis at sufficiently large energies.