相关论文: On cosmic natural selection

We explore possible effects of vacuum energy on the evolution of black holes. If the universe contains a cosmological constant, and if black holes can absorb energy from the vacuum, then black hole evaporation could be greatly suppressed.…

Smolin has put forward the proposal that the universe fine tunes the values of its physical constants through a Darwinian selection process. Every time a black hole forms, a new universe is developed inside it that has different values for…

Primordial black hole formation by cosmic string collapse is reconsidered when the winding number of the string is larger than the unity. The line energy density of the multiple winding string becomes greater than that of the single winding…

One way to explain the present acceleration of the Universe is Einstein's cosmological constant. It is quite likely, in view of some recent studies, that a time-dependent equation of state had caused the Universe to evolve from an earlier…

In a recent work we have argued that nosy energy momentum diffusion due to space-time discreteness at the Planck scale (naturally expected to arise from quantum gravity) can be responsible for the generation of a cosmological constant…

General expressions are given for the generation of Primordial Black Holes (PBH) in a universe with a presently accelerated expansion due to a(n effective) cosmological constant. We give expressions both for a powerlaw scalefree primordial…

Black hole formation may occur if the spectrum of the curvature perturbation \zeta increases strongly as the scale decreases. As no such increase is observed on cosmological scales, black hole formation requires strongly positive running n'…

I make a number of comments about Smolin's theory of Cosmic Natural Selection.

A cosmological scenario which explains the values of the parameters of the standard models of elementary particle physics and cosmology is discussed. In this scenario these parameters are set by a process analogous to natural selection…

It is known that there is a quantum mechanical tunneling process which, through nucleation of a membrane, induces a transition between two de Sitter spaces, lowering the cosmological constant. It is shown in this paper that a different,…

The problem of making predictions from theories that have landscapes of possible low energy parameters is reviewed. Conditions for such a theory to yield falsifiable predictions for doable experiments are given. It is shown that the…

The metric of a higher-dimensional dilaton black hole in the presence of a cosmological constant is constructed. It is found that the cosmological constant is coupled to the dilaton in a non-trivial way. The dilaton potential with respect…

When the cosmological constant, $\Lambda$, is interpreted as a thermodynamic variable in the study of black hole thermodynamics a very rich structure emerges. It is natural to interpret $\Lambda$ as a pressure and define the…

In the Letter [1] (also [2]) there is a claim that the generalised second law of thermodynamics (entropy increase) for black holes provides some limits on the rate of variation of the fundamental constants of nature (electric charge e,…

We argue that production of charged black hole pairs joined by a cosmic string in the presence of a magnetic field can be analyzed using the Ernst metric. The effect of the cosmic string is to pull the black holes towards each other,…

The observed value of the cosmological constant poses large theoretical problems. We find that topology of the Universe provides a natural source for it. Restricting dynamically an Einstein-Cartan gravity to General Relativity in our…

We argue that primordial black-hole formation must be described by means of extreme-value theory. This is a consequence of the large values of the energy density required to initiate the collapse of black holes in the early Universe and the…

We show how the Weyl formalism allows metrics to be written down which correspond to arbitrary numbers of collinear accelerating neutral black holes in 3+1 dimensions. The black holes have arbitrary masses and different accelerations and…

We show that the cosmological constant may be reduced by thermal production of membranes by the cosmological horizon, analogous to a particle ``going over the top of the potential barrier", rather than tunneling through it. The membranes…

For Lee Smolin, our universe is only one in a much larger cosmos (the Multiverse) - a member of a growing community of universes, each one being born in a bounce following the formation of a black hole. In the course of this, the values of…