Memory Networks with Asymmetric Bonds

The properties of associative memory networks with asymmetric interactions between the units are investigated for a class of analog networks subject to thermal noise (Langevin models). The results indicate that the memory states are not seriously degraded; their critical temperature is simply lowered from its value in the corresponding symmetric model. The spin glass states, which occur in the symmetric case when the number of memories becomes a finite fraction of the number of units in the system, are rendered unstable by the introduction of asymmetry. This suggests that asymmetric couplings may improve the retrieval of desired memory states by eliminating the spin glass states.