  In this thesis, several color-superconducting phases where quarks of the same
flavor form Cooper pairs are investigated. In these phases, a Cooper pair
carries total spin one. A systematic classification of theoretically possible
phases, discriminated by the color-spin structure of the order parameter and
the respective symmetry breaking pattern, is presented. In the weak-coupling
limit, i.e., for asymptotically high densities, a universal form of the QCD gap
equation is derived, applicable to arbitrary color-superconducting phases. It
is applied to several spin-one and spin-zero phases in order to determine their
energy gaps and critical temperatures. In some of the spin-one phases the
resulting gap function is anisotropic and has point or line nodes. It is shown
that the phases with two different gaps violate the well-known BCS relation
between the critical temperature and the zero-temperature gap. Moreover, the
screening properties of color superconductors regarding gluons and photons are
discussed. In particular, it turns out that, contrary to spin-zero color
superconductors, spin-one color superconductors exhibit an electromagnetic
Meissner effect. This property is proven by symmetry arguments as well as by an
explicit calculation of the gluon and photon Meissner masses.
