[iranbanoo]

اسمشون رو که نشنیدم ولی توضیحی که دادی خیلی گنگ بود!:))
تغییر ناپذیر از چه لحاظ؟از اینکه نمیشه در زمان دستکاری کرد؟

In minisuperspace approximations, we only have one Hamiltonian constraint (instead of infinitely many of them).In fact, the principle of general covariance in general relativity implies that global evolution per se does not exist; the time is just a label we assign to one of the coordinate axes. Thus, what we think about as time evolution of any physical system is just a gauge transformation, similar to that of QED induced by U(1) local gauge transformation where plays the role of local time. The role of a Hamiltonian is simply to restrict the space of the "kinematic" states of the Universe to that of "physical" states - the ones that follow gauge orbits. For this reason we call it a "Hamiltonian constraint." Upon quantization, physical states become wave functions that lie in the kernel of the Hamiltonian operator.
In general, the Hamiltonian vanishes for a theory with general covariance or time-scaling invariance.

Wheeler–DeWitt equation - Wikipedia, the free encyclopedia

گویا در این معادله با کوانتیده کردن کانونی نظریه ی نسبیت اینشتین معادله ای فاقد متغیر زمان به دست اومده