The set of these states allowed by consistent theories is measure zero within a larger set that Cumrun Vafa called the “swampland.” This state is Poincaré-invariant, cyclic, (10[1])and unique as a consequence of the Wightman axioms. (-5[1])Sidney Coleman proposed a mechanism in Kaluza–Klein theories where the decay of a metastable one of these states is caused by bubble (10[1])nucleation. (-5[1])In the (10[1])Fock space construction, repeatedly applying the creation operator to this state generates an n-particle Fock (10[1])state. The Casimir (10[2])effect arises (10[2])from (10[1])a (10[1])non-zero (10[1])value (10[1])of this state’s expectation (10[1])value. (10[4]-5[1])The (10[1])self-energy of the photon causes (10[1])this state’s namesake (10[1])“polarization.” (10[1])Virtual (10[1])particles spontaneously emerge and annihilate from this state. (-5[3])For 10 points, (10[2]-5[1])name this lowest quantum (-5[1])state (-5[1])consisting (-5[1])of empty space. (10[1])■END■ (10[10]0[3])