Variational approach to relative entropies with an application to QFT
Abstract
We define a new divergence of von Neumann algebras using a variational expression similar in nature to Kosaki’s formula for Umegaki’s relative entropy. Our divergence satisfies several of the usual desirable properties, upper bounds the sandwiched Renyi entropy and reduces to the fidelity in a limit. As an illustration, we use the formula in quantum field theory to compute our divergence between the vacuum in a bipartite system and an “orbifolded”—in the sense of a conditional expectation—system in terms of the Jones index. We take the opportunity to point out an entropic certainty relation associated with an inclusion of von Neumann factors related to the relative entropy. This certainty relation has an equivalent formulation in terms of error correcting codes.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1828397
- Journal Information:
- Letters in Mathematical Physics, Journal Name: Letters in Mathematical Physics Journal Issue: 6 Vol. 111; ISSN 0377-9017
- Publisher:
- Springer Science + Business MediaCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
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