Bias-exchange Metaynamics is a metadynamics-based approach which involves running of several replicas of MD simulations where each run is biased with metadynamics along a different collective variable. This approach is particularly very useful for sampling rare events in very complex process where many collective variables (usually more than 3) are relevant for the process under investigation.
In BEMD, several replicas of metadynamics simulations are run for the same system at the same temperature, with each replica biased by a time-dependent potential acting on a different set of CVs. These replicas are then periodically allowed to exchange their configurations, thereby allowing the biasing of a virtually unlimited number of CVs simultaneously. There is a low-dimensional bias acting on each replica which helps the system to overcome free energy barriers and the periodic exchange between different replicas makes it possible to explore a complex multidimensional free energy landscape with high efficiency.
For more information on Bias-exchange Metadynamics (BEMD), please refer to the Piana and Laio, 2007
For examples of previously performed studies in which Bias-exchange Metadynamics (BEMD) was the primary method used, see the following example cases: