postmeanfield

Postmeanfield is a term used in computational physics and chemistry to describe methods that go beyond the standard mean-field approximation. The mean-field approximation simplifies complex many-body problems by assuming that each particle interacts with an average field created by all other particles, rather than with each individual particle. This approach is computationally efficient but neglects correlations between particles.

Postmeanfield methods aim to correct for these neglected correlations. They typically involve including terms that account for the interactions between pairs of particles or higher-order correlations. Common postmeanfield techniques include configuration interaction (CI), coupled cluster (CC) theory, and various perturbation theory approaches. These methods generally lead to more accurate results than mean-field theories, especially for systems where electron correlation or quantum entanglement plays a significant role.

The development of postmeanfield methods has been crucial for achieving high accuracy in areas such as electronic structure calculations for molecules and condensed matter systems, quantum magnetism, and quantum information theory. While computationally more demanding than mean-field approaches, the improved accuracy provided by postmeanfield techniques is often essential for making reliable predictions and understanding complex physical phenomena. The choice of a specific postmeanfield method depends on the system being studied and the desired level of accuracy.