TY - JOUR A2 - Petkou, Anastasios AU - Iihoshi, Masao AU - Ketov，谢尔盖·v . PY - 2008 DA - 2009/01/22 TI - Superstrings-Induced四维重力及其应用宇宙学SP - 521389六世- 2008 AB -我们复习四阶的状态(四次时空曲率)引起的超弦/ m理论(紧化warpedtorus)领导对雷吉slope parameter, andstudy their (nonperturbative) impact on the evolution of the Hubble scalein the context of the four-dimensional FRW cosmology. After taking intoaccount the quantum ambiguities in the definition of the off-shell superstringeffective action, we propose the generalized Friedmann equations, find theexistence of their (de Sitter) exact inflationary solutions without a spacetimesingularity, and constrain the ambiguities by demanding stability andthe scale factor duality invariance of our solutions. The most naive (Bel-Robinson tensor squared) quartic terms are ruled out, thus giving the evidencefor the necessity of extra quartic (Ricci tensor-dependent) terms inthe off-shell gravitational effective action for superstrings. Our methods aregeneralizable to the higher orders in the spacetime curvature. SN - 1687-7357 UR - https://doi.org/10.1155/2008/521389 DO - 10.1155/2008/521389 JF - Advances in High Energy Physics PB - Hindawi Publishing Corporation KW - ER -