Gravity and Electromagnetism as Collective Phenomena of Fermion-Antifermion Pairs

Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but it is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: dSBH=−AdK+dMTBH, where the gravitational coupling K=1/4G, M is the black hole mass, A is the area of horizon, and TBH is Hawking temperature. From this first law, it follows that the dimensionless quantity M2/K is the adiabatic invariant, which, in principle, can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. Using the Painleve–Gullstrand metric, which in condensed matter is known as acoustic metric, we calculate the quantum tunneling from the black hole to the white hole. The obtained tunneling exponent suggests that the temperature and entropy of the white hole are negative.

Emergent gravity requires kinematic nonlocality

This Letter refines arguments forbidding nonlinear dynamical gravity from appearing in the low energy effective description of field theories with local kinematics, even for those with instantaneous long-range interactions. Specifically, we note that gravitational theories with universal coupling to energy-an intrinsically nonlinear phenomenon-are characterized by Hamiltonians that are pure boundary terms on shell. In order for this to be the low energy effective description of a field theory with local kinematics, all bulk dynamics must be frozen and, thus, irrelevant to the construction. The result applies to theories defined either on a lattice or in the continuum, and requires neither Lorentz invariance nor translation invariance.

Exact scale invariance of composite-field coupling constants

We show that the coupling-constant of a quantum-induced composite field is scale invariant due to its compositeness condition. It is first demonstrated in next-to-leading order in 1/N in typical models, and then we argue that it holds exactly.