When one applies block spin scheme on Ising model, what's the value for block spin? If we set the average value for spin in a block, it should not be ±1 anymore. But if so, is the transfer matrix is still two dimensional?
Is the block spin scheme the most popular of them?There are several different schemes. For example, one can do it using either decimation or majority rule.
https://arxiv.org/abs/0905.2601 (majority rule)
The variant schemes are all forms of "block spin". The original block spin is from Kadanoff https://journals.aps.org/ppf/abstract/10.1103/PhysicsPhysiqueFizika.2.263, but I think nowadays the term refers to all variant schemes in which the underlying idea is the same.Is the block spin scheme the most popular of them?