In physics, the Leggett inequalities,[1] named for Anthony James Leggett, who derived them, are a related pair of mathematical expressions concerning the correlations of properties of entangled particles.
(As published by Leggett, the inequalities were exemplified in terms of relative angles of elliptical and linear polarizations.)
The results of experimental tests in 2007 and 2010 have shown agreement with quantum mechanics rather than the Leggett inequalities.
[2][3] Given that experimental tests of Bell's inequalities have ruled out local realism in quantum mechanics, the violation of Leggett's inequalities is considered to have falsified realism in quantum mechanics.
[4] In quantum mechanics "realism" means "notion that physical systems possess complete sets of definite values for various parameters prior to, and independent of, measurement".