Heretofore unpublished Einstein paper [1931] and commentary

 Abstract...

We present a translation and analysis of an unpublished manuscript by Albert Einstein in which he proposed a 'steady-state' model of the universe. The manuscript appears to have been written in early 1931 and demonstrates that Einstein once considered a cosmic model in which the mean density of matter in an expanding universe remains constant due to a continuous creation of matter from empty space, a process he associated with the cosmological constant. This model is in marked contrast to previously known Einsteinian models of the cosmos (both static and dynamic) but anticipates the well-known steady-state theories of Hoyle, Bondi and Gold. We find that Einstein’s steady-state model contains a fundamental flaw and suggest it was discarded for this reason. We also suggest that he declined to try again because he found more sophisticated versions rather contrived. The manuscript is of historical significance because it reveals that Einstein debated between steady-state and evolving models of the cosmos decades before a similar debate took place in the cosmological community.

"Einstein’s steady-state model of the universe" by Cormac O’Raifeartaigh, Brendan McCann, Werner Nahm and Simon Mitton