The detection of ultra-high-energy (UHE) neutrinos, with energy in excess of 108 GeV, is an important key to solving the mystery of the origin of UHE cosmic rays. The detection of UHE cosmogenic neutrinos will confirm the photo-dissociation of UHE cosmic rays and the identification of the sources of UHE neutrinos will help to identify the sources of UHE cosmic rays.
The flux of these UHE neutrinos is expected to be low and their detection is a challenge. We present the Giant Radio Array for Neutrino Detection, GRAND, that is based on proven methods of radio frequency detection of extensive air-showers, which will allow for a huge exposure at a relatively modest price.
On top of discovering UHE neutrinos, GRAND will be able to investigate many other science topics, including neutrino physics, UHE gamma-ray detection, UHE cosmic ray science with very large statistics, the detection of fast radio bursts and giant radio pulses, and a measurement of the epoch of reionisation.
The R&D and different initial phases of development of GRAND, and the physics reach for these research topics will be discussed.