---
abstract: |
    We calculate the production of the gravitational waves from a double inflation model with lattice simulations. Between the two inflationary stages, gravitational waves with a characteristic frequency are produced by fluctuations of the scalar fields enhanced through parametric resonance. The wavelength of the produced gravitational waves gets extra redshift during the second inflationary stage and it can be in the observable range for the direct gravitational wave detectors. It is found that there is a possibility for the produced gravitational waves to be detected in the planned experiments.\
---

ICRR-Report-602-2011-19\
IPMU 11-0213

1.35cm

[ ]{}

1.2cm

Masahiro Kawasaki$^{a,b}$, Ken’ichi Saikawa$^c$ and Naoyuki Takeda$^a$\
0.4cm

[ *$^a$Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa City, Chiba, 277-8582, Japan*]{}\
[*$^b$Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa City, Chiba 277-8568, Japan*]{}\
[*$^c$Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8511, Japan*]{}\

Introduction {#sec:intro}
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The general relativity proposed by Einstein predicts the existence of the gravitational waves, which are the distortions of space-time geometry propagating through space as waves. Though it is indirect, there is strong evidence for the 