# Open Problems

## List of open problems

**This page contains information taken directly from Reinhard Werner's webpage.**

## Suggested further problems

We, the administrators of the Hannover open problem pages, will periodically check these contributions and move the ones we find most interesting to the main list.

Please leave your contact information so we can add it as in the list above.

Below is a very short sample problem with the main sections.

### Maximal rate function for estimation

#### Problem

Show that there is no state estimation procedure whose large deviation rate function is equal to the relative entropy.

#### Background

It is known from hypothesis testing that the relative entropy is an upper bound to the rate function.

#### Literature

- M. Keyl, Quantum state estimation and large deviations,

Last modified:

Monday, October 26, 2015 - 17:56