  In the 60's Professor Chen Ping Yang with Professor Chen Ning Yang published
several seminal papers on the study of Bethe's hypothesis for various problems
of physics. The works on the lattice gas model, critical behaviour in
liquid-gas transition, the one-dimensional (1D) Heisenberg spin chain, and the
thermodynamics of 1D delta-function interacting bosons are significantly
important and influential in the fields of mathematical physics and statistical
mechanics. In particular, the work on the 1D Heisenberg spin chain led to
subsequent developments in many problems using Bethe's hypothesis. The method
which Yang and Yang proposed to treat the thermodynamics of the 1D system of
bosons with a delta-function interaction leads to significant applications in a
wide range of problems in quantum statistical mechanics. The Yang and Yang
thermodynamics has found beautiful experimental verifications in recent years.
