Emergent Gravity from an Augmented Variational Principle

Augmented Variational Principles and Relative Conservation Laws in Classical Field Theory

Augmented variational principles are introduced in order to provide a definition of relative conservation laws. As it is physically reasonable, relative conservation laws define in turn relative conserved quantities which measure, for example, how much energy is needed in a field theory to go from one configuration (called the reference or vacuum) to another configuration (the physical state of the system). The general prescription we describe solves in a covariant way the well known observer dependence of conserved quantities. The solution found is deeply related to the divergence ambiguity o…

Geometrization of gravito-electromagnetic interactions from boundary conditions in the variational principle

We study the conditions of integrability when the boundary terms are considered in the variation of the geometric contribution of the Einstein-Hilbert action. We explore the emergent physical dynamics that is obtained when we make a displacement from a background Riemann manifold to an extended one, on which the non-metricity is nonzero. Under these circumstances, a classical description of electrodynamics and non-perturbative gravitational waves are considered in the extended manifold, when we variate the action.

近核领域中量子简化解环引力的涌现Thiemann相干态

Emergent Thiemann coherent states in the near-kernel sector of quantum reduced loop gravity

本文研究了量子简化解环引力中一顶点模型的哈密顿约束算子的近核领域，采用神经量子态的变分蒙特卡洛方法，发现近核态分为三种不同类别，其中一种与减少的Thiemann相干态具有近单位保真度，提供了近核领域 semiclassical 组织的证据。

Grin of the Cheshire cat: Entropy density of spacetime as a relic from quantum gravity

There is considerable evidence to suggest that the field equations of gravity have the same status as, say, the equations describing an emergent phenomenon like elasticity. In fact, it is possible to derive the field equations from a thermodynamic variational principle in which a set of normalized vector fields are varied rather than the metric. We show that this variational principle can arise as a low energy ($L_P = (G\hbar/c^3)^{1/2} \to 0$) relic of a plausible nonperturbative effect of quantum gravity, viz. the existence of a zero-point-length in the spacetime. Our result is nonperturbati…