Nobel Prize in Physics in 1962 2026-10-18
Awarded to Lev Davidovich Landau for pioneering theories of condensed matter, especially liquid helium.[ref]
The Nobel Prize in Physics 1962 by Nobel Prize Outreach. Individual official award summary: sole laureate and condensed-matter/liquid-helium theory motivation.
Second sound 2026-10-18
Second sound is an entropy and temperature wave. At negligible thermal expansion, it has almost zero net mass flux. Lev Davidovich Landau predicted two sound modes in 1941.[ref]
The Theory of Superfluidity of Helium II by Lev Davidovich Landau. Landau, §8, pp.515–516