62,367 research outputs found
Inflation and the quantum measurement problem
We propose a solution to the quantum measurement problem in inflation. Our model treats Fourier modes of cosmological perturbations as analogous to particles in a weakly interacting Bose gas. We generalize the idea of a macroscopic wave function to cosmological fields, and construct a self-interaction Hamiltonian that focuses that wave function. By appropriately setting the coupling between modes, we obtain the standard adiabatic, scale-invariant power spectrum. Because of central limit theorem, we recover a Gaussian random field, consistent with observations
Chern-Simons flows on Aloff-Wallach spaces and Spin(7)-instantons
Due to their explicit construction, Aloff-Wallach spaces are prominent in
flux compactifications. They carry G_2-structures and admit the G_2-instanton
equations, which are natural BPS equations for Yang-Mills instantons on
seven-manifolds and extremize a Chern-Simons-type functional. We consider the
Chern-Simons flow between different G_2-instantons on Aloff-Wallach spaces,
which is equivalent to Spin(7)-instantons on a cylinder over them. For a
general SU(3)-equivariant gauge connection, the generalized instanton equations
turn into gradient-flow equations on C^3 x R^2, with a particular cubic
superpotential. For the simplest member of the Aloff-Wallach family (with
3-Sasakian structure) we present an explicit instanton solution of tanh-like
shape.Comment: 1+17 pages, 1 figur
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