Why%20minimize%20the%20variance?

1
Why minimize the variance?
Bressanini et. Al. JCP 116, 5345 (2002)
Why not these? Or others?
Why sometimes optimization goes bad?
2
Standard derivation Integrals (continuous)
Alternative derivation Fitting process
(discrete)
Maximize probability (Maximum likelyhood
estimator)

• Need to assume gaussian deviations

3
Is the local energy distribution really gaussian?
NO
4
Helium trimer