Sphere Renyi entropies

Understand

I give some scalar field theory calculations on a d-dimensional lune of arbitrary angle, evaluating, numerically, the effective action which is expressed as a simple quadrature, for conformal coupling.

• Using this, the entanglement and Renyi entropies are computed.
• Massive fields are also considered and a renormalisation to make the (one-loop) effective action vanish for infinite mass is suggested and used, not entirely successfully.
• However a universal coefficient is derived from the large mass expansion.