QCA have attracted a lot of attention as a result of its extremely small feature size (at the molecular or even atomic scale) and its ultra-low power consumption, making it one candidate for replacing CMOS technology.
Models which have been proposed recently impose further conditions, e.g. that quantum cellular automata should be reversible and/or locally unitary, and have an easily determined global transition function from the rule for updating individual cells.
The first formal model of quantum cellular automata to be researched in depth was that introduced by John Watrous.
[1] This model was developed further by Wim van Dam,[12] as well as Christoph Dürr, Huong LêThanh, and Miklos Santha,[13][14] Jozef Gruska.
[18][19] Models of quantum cellular automata have been proposed by David Meyer,[20][21] Bruce Boghosian and Washington Taylor,[22] and Peter Love and Bruce Boghosian[23] as a means of simulating quantum lattice gases, motivated by the use of "classical" cellular automata to model classical physical phenomena such as gas dispersion.