Dirac's Principle Research Articles

Space-Like Form of Bethe–Salpeter Equation: Bound State**The project supported by National Natural Science Foundation of China, the Foundation of National Education Committee and University of Science and Technology of China for the Excellent Personnel Returned to the Country

According to Dirac's principle, we apply the space-like consistency conditions in a relativistic theory to two-particle system and then define the space-Like wavefunctions through introducing a space-like factor, which is equivalent to Bethe–Salpeter wavefunction in physical content. The space-like form of Bethe–Salpeter equation of bound states is derived in terms of the universal rearranging technology of interaction kernel. Its advantages are of explicit Lorentz-covariant form and the difficulty of ghost states is automatically overcome. We also discuss the normalization condition of the space-like function.

On the consequences of a cosmological model with a time-dependent cosmological «constant» and the relationship between Einstein equivalence principle, Mach's principle and dirac's principle

Within the framework of a cosmological model with a time-dependent cosmological constant Λ, we examine the evolutionary behaviour of the Universe during the radiation-dominated and matter-dominated eras. The smallness of the cosmological constant and the origin of galaxy formation are explained. For a dust-filled universe withp≃0, the model yields a cosmological solutionk=−1,R∼t. The relationship among Einstein equivalence principle, Mach's principle and Dirac's principle is also elucidated through the time-dependent Λ. It is shown that these principles are compatible, and Mach's principle and Dirac's principle can be viewed as an initial-value condition and a dynamic consequence of Einstein's equations (satisfying Einstein equivalence principle), respectively.

Dirac's principle and variability of fundamental constants

A hypothesis is suggested of e 4α t, h ̵ 2 α t, G = const which logically follows from Dirac's principle of large dimensionless quantities (∼10 40) being proportional to the age of the universe, t. Dirac's principle is generalized for both the weak and strong interactions, and corollaries are pointed out and treated in terms of the above hypothesis.

DIRAC'S COSMOLOGY AND RADIOACTIVE DATING

It has long been recognized that Dirac's principle might imply that the rate of β decay would vary with the age of the universe. If so, the radioactive ages of meteorites and terrestrial rocks as indicated on the one hand by α decay and on the other by β decay should differ. However, the comparison of these ages is complicated by a large uncertainty in the decay constant for Rb87. Thus the age data must be analyzed to determine the decay constant most compatible with the particular theory of β decay which is used. Using this best decay constant for each theory, we find that the data are more consistent with a β decay rate independent of the age of the universe than with the dependence implied by the Dirac principle.