  We apply a new technique, the mutual information (MI) from information
theory, to time-distance helioseismology, and demonstrate that it can
successfully reproduce several classic results based on the widely used
cross-covariance method. MI quantifies the deviation of two random variables
from complete independence, and represents a more general method for detecting
dependencies in time series than the cross-covariance function, which only
detects linear relationships. We provide a brief description of the MI-based
technique and discuss the results of the application of MI to derive the solar
differential rotation profile, a travel-time deviation map for a sunspot and a
time-distance diagram from quiet Sun measurements.
