Yang's Gravitational Field Equations

Gravitational Gauge Theory Developed Based on the Stephenson-Kilmister-Yang Equation

“…In 1974 Yang considered an integral formalism of gauge fields and suggested such a new gravitational field equation [16], where the Christoffel symbol (Levi-Civita connection) serves as a non-Abelian gauge field [16]. Pavelle immediately pointed out that this gravitational field equation is identical with that proposed by Kilmister in 1959 [17], and then in the references published later, some authors referred to it as the Kilmister-Yang equation [18]. But actually, it might be Stephenson who was the first one to propose such a kind of theory (even one year earlier than Kilmister did) [19].…”

“…Some specific physical properties such as the monopole gravitational radiation and the Birkhoff theorem relevant to the SKY equation were discovered [22]. The static, spherically symmetric solution to the SKY equation was obtained, which showed that the Solar experiments cannot yet distinguish between the SKY equation and the Einstein vacuum gravitational equation [17]. Though it has some "unphysical" solutions, the SKY equation has already contained all the solutions of the Einstein vacuum field equation.…”

Spring Theory as an Approach to the Unification of Fields

“…Properties of these equations had been studied by various authors [6] [7] [8]. Pavelle [6] pointed out that Yang's pure space is non-physical unless the cosmological constant remains in Einstein's field equations which was later verified by Mielke [8].…”

Yang's Gravitational Theory

“…As a third order non-linear system, Yang's equations are significantly more complex than those of either general relativity or Yang-Mills theory, both of which are second order. Nonetheless, shortly after Yang published his paper a number of exact solutions were discovered by Pavelle [2] [3], Thompson [4][5], Ni [6] and Chen-Long et al [7][8].…”