A variational method from the variance of energy
Dipartimento di Fisica e Astronomia, Universitá di Catania, INFN Sez. di Catania and INFM UdR di Catania, via S. Sofia 64, 95123, Catania, Italy
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A variational method is studied based on the minimum of energy variance. The method is tested on exactly soluble problems in quantum mechanics, and is shown to be a useful tool whenever the properties of states are more relevant than the eigenvalues. In quantum field theory the method provides a consistent second-order extension to the Gaussian effective potential.
PACS. 03.65.-w, 11.10.-z, 05.30.-d
© Springer-Verlag, 2005