Inflation is modeled by the dynamics of a scalar field.  One then introduces perturbations in the scalar field.  One then quantizes the perturbations in terms of quantum fields.  One can then calculate the two-point function of these field variables.  And one can then extract the “Power spectrum” from this 2-pt function.  And…. eventually this produces a description of the CMB that can be compared, very favorably, with observations.

Inflationary basics:  Takes the universe from a relatively generic state after the Planck era to a state with the seeds of cosmic structure (which we then observe as the CMB, as modeled by the beach ball).

Daniel’s topic:  the emergence of the seeds of structure from quantum fluctuations during the inflationary cosmological era.

This is a situation in which GR, QM, and observation come together (witness the beach ball!).

Recap of the measurement problem:  2 different types of evolution (Penrose’s U Process and R Process).  Why not take Penrose’s suggestion and try to address the measurement problem by incorporating some aspect of gravity?

Daniel thinks philosophers can contribute!  (He even has a beach ball prop.)

Discussion:

Audience:  Philosophers can explain what “beauty” in a final theory could be like.

James:  Really good art historians become physicists, not philosophers.

Audience:  Conceptual work can be contributed by philosophers.

James:  But who can do it when it’s coupled technically with the physics?

James is unclear what the role for philosophers is here.  There are good philosophers, and there are good physicists, but are there good philosopher-physicists out there?

limitations of the method:

– no guarantees

– progress is slow

– problems of interpretation

Two other approaches:  hydrodynamic and condensed matter.

James:  Intriguing ideas but not well-developed as yet.

Virtues of general method:

– it’s a *method* and not speculative ontology.

– it holds promise of making contact with other approaches

– self-correcting

– it’s worked in the past

Basic tenets of stochastic gravity:

– assume a complete micro theory incorporating gravity

– assume it’s a quantum system

It must be open.  (And a couple other characteristics that flew by me…)

One direction is “kinetic theory”…