[@ander; @tom].

The conventional microscopic theory (CMT) [@ander; @tom] of a [*system of interacting bosons*]{} (SIB), such as liquid $^4$He, uses single particle basis (SPB) for its description. It considers that particles occupy different quantum states of a single particle placed in a box of volume V of the system and these states are described by plane waves ($u_k(r)$ = $A\exp{(i{\bf k}.{\bf r})}$ where symbols have their usual meaning); in other words a single particle represents the basic unit with an assumption that its momentum remains a good quantum number even in the superfluid state of the system. The theory concludes that: (1) the state of liquid $^4$He at a temperature ($T$) can be identified by the momentum distribution $N(p)$ of its particles where different number of particles $N_p(T)$ have different $p$, and (2) with the onset of superfluid transition, $N(p)$ does not change significantly except for the existence of a fraction of particles, $n_{p=0}(T) = N_{p=0}/N$ having $p=0$ in LT phase. Accordingly, even the ground state (G-state) of liquid $^4$He has different number of atoms in the states of different momenta, [*viz.*]{}, $N_{p=0}$ in $p$(=$\hbar k) = 0$ state and $N_{p\not=0}$ in several states of non-zero momenta, [**k**]{}$_1$, [**k**]{}$_2$, 