Strongly allowed transitions integral

The computation of quantum many-body effects requires additional effort compared to classical cases. This holds in particular if strong collective phenomena such as phase transitions are considered. The path integral approach to critical phenomena allows the computation of collective phenomena at constant temperature — a condition which is preferred experimentally. Due to the link of path integrals to the partition function in statistical physics, methods from the latter — such as Monte Carlo simulation techniques — can be used for efficient computation of quantum effects. 

A strong overlap of initial and final wave functions is expected for mirror nuclei, in which the mass numbers are identical, but the atomic number in one nucleus is equal to the neutron number of the other. The large overlap integral results in a very low fi value (superallowed transitions). Most of the known P emitters decay by allowed or superallowed transitions. Among the light nuclides there are many mirror pairs. 

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