  Metallic states coined strange metal (SM), with robust linear-$T$
resistivity, have been widely observed in many quantum materials under strong
electron correlation, ranging from high-$T_{c}$ cuprate superconductor, organic
superconductor to twisted multilayer graphene and MoTe$_{2}$/WSe$_{2}$
superlattice. Despite decades of intensive studies, the mystery of strange
metal still defies any sensible theoretical explanation and has been the key
puzzle in modern condensed matter physics. Here, we solve a doped Mott
insulator model, which unambiguously exhibits SM phenomena accompanied with
quantum critical scaling in observables, e.g. resistivity, susceptibility and
specific heat. Closer look at SM reveals the breakdown of Landau's Fermi liquid
without any symmetry-breaking, i.e. the violation of Luttinger theorem.
Examining electron's self-energy extracted from numerical simulation provides
the explanation on the origin of linear-$T$ resistivity and suggests that the
long-overlooked static fluctuations in literature play an essential role in
non-Fermi liquid behaviors in correlated electron systems.
