Ivar Giaever (Norwegian: Giæver, IPA: [ˈìːvɑr ˈjèːvər]; born April 5, 1929) is a Norwegian-American engineer and physicist who shared the Nobel Prize in Physics in 1973 with Leo Esaki and Brian Josephson "for their discoveries regarding tunnelling phenomena in solids".

[2] In 1975, he was elected as a member into the National Academy of Engineering for contributions in the discovery and elaboration of electron tunneling into superconductors.

He moved to the United States four years later, joining General Electric's Corporate Research and Development Center in Schenectady, New York, in 1958.

[5] Giaever's experiments demonstrated the existence of an energy gap in superconductors, one of the most important predictions of the BCS theory of superconductivity, which had been developed in 1957.

In 1969, he researched biophysics for a year as a fellow at Clare Hall, University of Cambridge, through a Guggenheim Fellowship, and he continued to work in this area after he returned to the US.