Based on the author's previous argument of the constant existence of the subject of quantum measurement in the framework of the classicalized holographic tensor network, for two quantum measuring systems $M_1$ and $M_2$ in the bulk spacetime, we calculate the result of the processes $(((M_1)_{\rm I}-M_1)_{\rm II}+M_2)_{\rm III}$ as the subject of quantum measurement. This process is obtained from the process $(((M_1)_{\rm I}+M_2)_{\rm II}-M_1)_{\rm III}$ by swapping processes II and III. The latter process is within the Lorentzian regime of spacetime and results in the quantum measuring system $M_2$. Therefore, we conclude that the objective result is also $M_2$.

In this article, we present a heuristic derivation of the on-shell equation of the Lorentzian classicalized holographic tensor network in the presence of a non-zero mass in the bulk spacetime. This derivation of the on-shell equation is based on two physical assumptions. First, the Lorentzian bulk theory is in the ground state. Second, the law of Lorentzian holographic gravity is identified with the time--energy uncertainty principle. The arguments in this derivation could lead to a novel picture of Lorentzian gravity as a quantum mechanical time uncertainty based on the holographic principle and Classicalization.

In three spacetime dimensions, we propose a generally covariant Lorentzian action of the classicalized holographic tensor network (cHTN) as the holographic reduction of the Einstein--Hilbert action of gravity in the presence of a negative cosmological constant. In this article, first, we investigate the properties of this Lorentzian action in the ground state. Next, based on the Euclidean action of the cHTN, we derive the gravity perturbation induced by a massive particle at rest in the cHTN as the Unruh effect. Finally, we view our holographic formulation of spacetime as a non-equilibrium second law subject to general covariance.

In the three-dimensional anti-de Sitter spacetime/two-dimensional conformal field theory correspondence, we derive the imaginary-time path-integral of a non-relativistic particle in the anti-de Sitter bulk space, which is dual to the ground state, from the holographic principle. This derivation is based on (i) the author's previous argument that the holographic principle asserts that the anti-de Sitter bulk space as a holographic tensor network after Classicalization has as many stochastic classicalized spin degrees of freedom as there are sites and (ii) the reinterpretation of the Euclidean action of a free particle as the action of classicalized spins.

It is a sort of ultimate question to examine the continuity of a quantum measurement subject theoretically and has not yet been resolved within a scientific framework.In this article, we approach this question and argue that the continuity of a quantum measurement subject follows as a fundamental consequence of the holographic principle after the Classicalization of the quantum state of the bulk space.

We argue that the flat spacetime with inexact quantum mechanics in it is dual to the de Sitter spacetime with exact quantum mechanics in it, and the positive cosmological constant of this de Sitter spacetime is in the second order of the degree of the violation of the bulk quantum mechanics in the flat spacetime. The flat spacetime is holographic and has a dual time-contracted boundary conformal field theory with two redefined central charges at null infinity. The vanishing smallness of the observed positive cosmological constant suggests the extraordinary exactness of the bulk quantum mechanics in the flat spacetime.