Positive energy and Poincare gauge theory

Some alternate theories of gravity fit the experimental evidence just as well as Einstein's theory. Such is the case for certain Poincare gauge theories. Hence, there is a need for a strong theoretical test. The requirement of positive total energy, recently established for Einstein's theory, promises to fulfill this need. The authors results to date lead them to expect that this test will eliminate almost all of the otherwise viable Poincare gauge theories