The goal of the work supported under this grant is to use LIGO to search for a background of gravitational radiation that originated in the Big Bang. An analogous background of electromagnetic origin was discovered fifty years ago, but it originated at a much later time in the evolution of the Universe. This search takes advantage of LIGO's high sensitivity at gravitational wave wavelengths that are sub-multiples of the interferometer arm length. In addition, at such wavelengths, the gravitational signal has a distinct spectral shape that can facilitate its identification in the presence of a much higher level of instrumental noise. The discovery of this effect would make possible a look at the earliest epoch of the cosmos and would drastically impact the understanding of our world. The analysis of the LIGO data to search for this effect requires algorithm development and large scale computing. This is ideal training for young scientists and students who thereby acquire skills valuable in all sectors of technology and of and its applications in our society.
