Baeriswyl, Dionys 2011-09-13 Variational wave functions are very useful for describing the panoply of ground states found in interacting many-electron systems. Some particular trial states are “adiabatically” linked to a reference state, from which they borrow the essential properties. A prominent example is the Gutzwiller ansatz, where one starts with the filled Fermi sea. A simple soluble example, the anisotropic XY chain, illustrates the adiabatic continuity of this class of wave functions. To describe symmetry breaking, one has to modify the reference state accordingly. Alternatively, a quantum phase transition can be described by a pair of variational wave functions, starting at weak and strong coupling, respectively. application/pdf https://folia.unifr.ch/global/documents/302315 https://folia.unifr.ch/documents/302315/files/bae_acb.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1002/andp.201100044 info:eu-repo/semantics/openAccess License undefined Annalen der Physik. - 2012, vol. 523, no. 8-9, p. 724–731 Strongly correlated electrons variational wave functions adiabatic continuity info:eu-repo/classification/udc/53 Adiabatic continuity and broken symmetry in many-electron systems: A variational perspective http://purl.org/coar/resource_type/c_6501