Giaever, Ivar (1929-), a Norwegian-born American physicist, shared the 1973 Nobel Prize in physics with Leo Esaki of Japan and Brian David Josephson of the United Kingdom. All three had done important research on electron tunneling through materials. Giaever's award was for his work on tunneling in materials showing superconductivity, the ability to conduct electrical current without resistance.

Tunneling is a means by which electric current flows at a higher rate than predicted by what are known as classical theories of physics, which treat electrons as though they were particles. But according to quantum mechanics, electrons have characteristics of waves as well as particles. Wave equations of quantum mechanics show how tunneling can occur.

Much of Giaever's research involved thin films (thin layers of conductive material forming part of an integrated circuit), in tunneling, and superconductivity. He has also done much research in the application of physics to biological problems.

Giaever was born in Bergen, Norway. From 1948 to 1952, he studied mechanical engineering at the Norwegian Institute of Technology. He served as a corporal in the Norwegian army from 1952 to 1953, then worked for a year as a patent examiner for the Norwegian government. In 1954, Giaever immigrated to Canada, and in 1956, he moved to the United States. He worked as an architect's assistant and a mathematician, and then in 1964 he obtained a Ph.D. degree in physics from the Rensselaer Polytechnic Institute (RPI) in Troy, New York. In the same year, he became a U.S. citizen.

Giaever worked for General Electric Research and Development Center from 1958 to 1988. In 1988, he became an institute professor at RPI; he worked concurrently as a professor at the University of Oslo, Norway.

Giaever is a fellow of the American Physics Society and a member of the National Academy of Sciences, the National Academy of Engineering, and the American Academy of Arts and Sciences, as well as several prestigious Norwegian scientific societies.