In 1992, E.E.Podkletnov and R.Nieminen find that, under certain conditions,
ceramic superconductor with composite structure has revealed weak shielding
properties against gravitational force. In classical Newton's theory of gravity
and even in Einstein's general theory of gravity, there are no grounds of
gravitational shielding effects. But in quantum gauge theory of gravity, the
gravitational shielding effects can be explained in a simple and natural way.
In quantum gauge theory of gravity, gravitational gauge interactions of complex
scalar field can be formulated based on gauge principle. After spontaneous
symmetry breaking, if the vacuum of the complex scalar field is not stable and
uniform, there will be a mass term of gravitational gauge field. When
gravitational gauge field propagates in this unstable vacuum of the complex
scalar field, it will decays exponentially, which is the nature of
gravitational shielding effects. The mechanism of gravitational shielding
effects is studied in this paper, and some main properties of gravitational
shielding effects are discussed.Comment: 13 pages, no figur