Sample interview questions: How do you approach the problem of baryogenesis and the origin of matter within the framework of string theory?
Sample answer:
Approaching Baryogenesis and the Origin of Matter in String Theory
Supersymmetry Breaking: String theory introduces supersymmetry, a symmetry between bosons and fermions. Breaking supersymmetry spontaneously can generate a nonzero value for the cosmological constant, driving the early universe through a phase transition that creates an excess of baryons over antibaryons.
Cosmic Inflation: String theory predicts extra dimensions that can undergo periods of rapid expansion, known as inflation. During inflation, the universe expands exponentially, diluting any existing baryon asymmetry. To preserve the asymmetry, a small but nonzero value for the baryon-to-photon ratio must be generated before inflation begins.
D-Brane Cosmology: String theory introduces D-branes, which are higher-dimensional objects that can interact with fundamental strings. D-brane collisions can produce baryons and antibaryons. In string cosmology, scenarios involving D-brane collisions are explored as a possible mechanism for baryogenesis.
Non-Supersymmetric String Models: The Landscape… Read full answer