## Wednesday, November 24, 2004

### Bubble Nucleation

Based on the no boundary proposal, I picture the origin of the universe, as like the formation of bubbles of steam in boiling water. Quantum fluctuations lead to the spontaneous creation of tiny universes, out of nothing. Most of the universes collapse to nothing, but a few that reach a critical size, will expand in an inflationary manner, and will form galaxies and stars, and maybe beings like us.

The images produce here of bubble formation are most pleasing to me, about what could have emerge from that early universe. If stringy components were evident and cosmic clumping rvealed as in previous post then how would such images lead to bubble nucleations as stringy cosmological patterns?

For such ideas to emerge in thinking there had to be a time when such conditions were conducive to bubble nucleation? Such energy considerations had to provide for these considerations to emerge so. How so?

First-order phase transitions (illustrated below) occur through the formation of bubbles of the new phase in the middle of the old phase; these bubbles then expand and collide until the old phase disappears completely and the phase transition is complete.

During a first-order phase transition, the matter fields get trapped in a false vacuum' state from which they can only escape by nucleating bubbles of the new phase, that is, the true vacuum' state.

G -> H -> ... -> SU(3) x SU(2) x U(1) -> SU(3) x U(1). Here, each arrow represents a symmetry breaking phase transition where matter changes form and the groups - G, H, SU(3), etc. - represent the different types of matter, specifically the symmetries that the matter exhibits and they are associated with the different fundamental forces of nature

In order for such thinking to produce the cosmos then we would have to understand its early conditions.

Physically, the effect can be interpreted as an object moving from the "false vacuum" (where = 0) to the more stable "true vacuum" (where = v). Gravitationally, it is similar to the more familiar case of moving from the hilltop to the valley. In the case of Higgs field, the transformation is accompanied with a "phase change", which endows mass to some of the particles.