Phase transition

We are all familiar with phase transition in our everyday life. Solid ice turns into liquid water when heated up, and liquid water turns into water vapor when more heat is supplied. The reverse process can also happen when the temperature drops.

There were also "phase transitions" happened in the very early Universe, but in a slightly different sense. At the temperature around 100 MeV, free quarks formed bound states called baryons, while free quarks and antiquarks formed bound states called mesons; this period is called QCD phase transition. At even higher temperature around 100 GeV, the initially-massless particles acquired mass due to symmetry breaking of the electroweak gauge group; this period is called electroweak phase transition.

If the old and the new states of the phase transition coexist, we say that it is a first-order phase transition (FOPT). A FOPT is not predicted by the Standard Model of particle physics, but is crucial to explain some mystery such as the matter-antimatter asymmetry. A FOPT also has rich consequent phenomenologies such as it can produce measurable Gravitational Waves or even Primordial Black Holes.

I'm interested in exploring the aspects of FOPT as well as their interesting observational consequences.

• Ngo Phuc Duc Loc, "Gravitational waves from burdened primordial black holes dark matter", Phys. Rev. D 111, 023509 (2025)

• Ngo Phuc Duc Loc, "Sphaleron bound in some nonstandard cosmology scenarios", Int. J. Mod. Phys. A 37, 2250153 (2022)

• Vo Quoc Phong, Phan Hong Khiem, Ngo Phuc Duc Loc, and Hoang Ngoc Long, "Sphaleron in the first-order electroweak phase transition with the dimension-six Higgs field operator", Phys. Rev. D 101, 116010 (2020)