  All ground states and low-lying excitations of a +/- I Ising spin glass model
on a cubic 4 x 4 x 4 lattice with periodical boundary conditions were
calculated using a method of combinatorical optimization. The structure of
states in the phase space is enlightened by a representation by means of
clusters in the configuration space and their connectivity. The relaxation
behaviour of the system can be described by random walks in the
high-dimensional phase space. Rewriting this task as an eigenvalue problem the
influence of `entropic barriers' in comparison with an unstructured system can
be studied, leading to a better understanding of the anomalous slow dynamic
behaviour.
