TY - JOUR
T1 - Quantum fluctuations in brane-world inflation without an inflaton on the brane
AU - Sago, Norichika
AU - Himemoto, Yoshiaki
AU - Sasaki, Misao
PY - 2002
Y1 - 2002
N2 - A Randall-Sundrum-type brane-cosmological model in which slow-roll inflation on the brane is driven solely by a bulk scalar field was recently proposed by Himemoto and Sasaki. We analyze their model in detail and calculate the quantum fluctuations of the bulk scalar field φ with m2 = V″(φ). We decompose the bulk scalar field into the infinite mass spectrum of four-dimensional fields; the field with the smallest mass square, called the zero mode, and the Kaluza-Klein modes above it with a mass gap. We find the zero-mode dominance of the classical solution holds if |m 2lm2 ≪ 1, where l̄ is the curvature radius of the effectively anti-de Sitter bulk, but it is violated if |l̄m 2lm2, though the violation is very small. Then we evaluate the vacuum expectation value 〈δφ2〉 on the brane. We find the zero-mode contribution completely dominates if |m 2l̄2 ≪ 1, similar to the case of classical background. In contrast, we find the Kaluza-Klein contribution is small but non-negligible if the value of |m2|l̄2 is large.
AB - A Randall-Sundrum-type brane-cosmological model in which slow-roll inflation on the brane is driven solely by a bulk scalar field was recently proposed by Himemoto and Sasaki. We analyze their model in detail and calculate the quantum fluctuations of the bulk scalar field φ with m2 = V″(φ). We decompose the bulk scalar field into the infinite mass spectrum of four-dimensional fields; the field with the smallest mass square, called the zero mode, and the Kaluza-Klein modes above it with a mass gap. We find the zero-mode dominance of the classical solution holds if |m 2lm2 ≪ 1, where l̄ is the curvature radius of the effectively anti-de Sitter bulk, but it is violated if |l̄m 2lm2, though the violation is very small. Then we evaluate the vacuum expectation value 〈δφ2〉 on the brane. We find the zero-mode contribution completely dominates if |m 2l̄2 ≪ 1, similar to the case of classical background. In contrast, we find the Kaluza-Klein contribution is small but non-negligible if the value of |m2|l̄2 is large.
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U2 - 10.1103/PhysRevD.65.024014
DO - 10.1103/PhysRevD.65.024014
M3 - Article
AN - SCOPUS:3543044819
VL - 65
JO - Physical review D: Particles and fields
JF - Physical review D: Particles and fields
SN - 1550-7998
IS - 2
M1 - 024014
ER -