Lambdavacuum solution

In general relativity, a lambdavacuum solution is an exact solution to the Einstein field equation in which the only term in the stress–energy tensor is a cosmological constant term. This can be interpreted physically as a kind of classical approximation to a nonzero vacuum energy.

Terminological note: this article concerns a standard concept, but there is apparently no standard term to denote this concept, so we have attempted to supply one for the benefit of .

The Einstein field equation is often written as

with a so-called cosmological constant term ${\displaystyle \Lambda \,g^{ab}}$. However, it is possible to move this term to the right hand side and absorb it into the stress–energy tensor ${\displaystyle T^{ab}}$, so that the cosmological constant term becomes just another contribution to the stress–energy tensor. When other contributions to that tensor vanish, the result

...
Wikipedia