This space for questions, ideas and workshop topics

Program Overview

Setting the tone and asking the big questions.

1. Universal terms in the entanglement entropy

"Short and long range" or "local and non-local" entanglement

What assumptions underlie these classifications? Violation of assumptions in Haah's cubic code?

Origin of universal terms in even vs. odd dimensions (CFTs)

Derivation of a-theorem in 3+1-D using strong subadditivity? Derivation of F-theorem in 2+1-D using QFT? higher dimensional analogues?

Gapless strongly interacting phases: analytical calculation of EE for spinon Fermi surface in two or three dimensions?

Universal topological data from ground state wavefunction for SPT (symmetry protected topological) phases? For 3+1-d topological phases with non trivial three loop braiding?

2. Decoding the wavefunction to obtain information not naively contained in the wavefunction

Entanglement Hamiltonian for the ground state of Lorentz invariant systems encode the original Hamiltonian.

Are there non-trivial examples without Lorentz invariance where we can deduce the Hamiltonian from the ground state wavefunction?

Eigenstate Thermalization (Ergodic systems) => Entanglement Hamiltonian for finite energy density states =~ the original Hamiltonian.

3. Quantum dynamics and entanglement

Origin of the linear in time entanglement growth after a global quench?

Ergodic vs. non-ergodic behavior (logarithmic in time growth in many body localization).

Equivalence between thermal and entanglement entropies at finite energy density in ergodic phases.

Signatures of quantum chaos? Relation to Lieb-Robinson bounds?

4. Calculational tools

"EE not a well defined quantity in QFT" (anonymous). How to make progress with analytical continuation related issues for Renyi Entropies e.g. two interval entropy in 1+1-D CFTs?

prospects and target systems where current methods can be applied?

novel techniques and algorithmic development.

relationship between the sign problem in quantum Monte Carlo and measuring entanglement entropy?

Can the von Neumann entanglement entropy be measured in Monte Carlo?

5. Measuring entanglement

Cancel your flights, do not miss next Tuesday's experimental talk by Rajibul Islam on measuring the 2nd Reyni entropy in ultra cold atoms.

Basic issue with von Neumann EE: it's a "state-dependent" operator. Can one measure state dependent operators of any kind in a experiment (modulo Renyi entropies which become state independent after taking n copies of the system)?

6. Holographic entanglement

First week focus with an introductory talk by Mukund Rangamani on Thursday at 11:00 AM.

Questions from the Discussion on c, a, and F-theorems

Led by John Cardy, Friday, April 4, 2015

1) What is the c-theorem in 2d? What are the different proofs? 2) What are its applications to condensed matter/QFT? 3) Which of these arguments extend to other even/odd d? (Can we make a table?) 4) What is the status of the a-theorem in d=4? 5) What are its potential applications? 6) What is the status of the F-theorem in 3d? 7) What are its potential applications? 8) Is there a higher-dimensional version of the boundary g-theorem? 9) Why does it seem so hard to prove monotonicity theorems given the universal nature of the RG?

Questions from the Discussion "What is a Phase"

Led by Frank Verstraete and David Perez-Garcia

Given two phases which have the same qualitative properties (e.g. exactly the same set of quasiparticles), can they be separated by a continuous phase transition?

## Program Overview

Setting the tone and asking the big questions.## 1. Universal terms in the entanglement entropy

## 2. Decoding the wavefunction to obtain information not naively contained in the wavefunction

## 3. Quantum dynamics and entanglement

## 4. Calculational tools

## 5. Measuring entanglement

## 6. Holographic entanglement

## Questions from the Discussion on c, a, and F-theorems

Led by John Cardy, Friday, April 4, 20151) What is the c-theorem in 2d? What are the different proofs?

2) What are its applications to condensed matter/QFT?

3) Which of these arguments extend to other even/odd d? (Can we make a table?)

4) What is the status of the a-theorem in d=4?

5) What are its potential applications?

6) What is the status of the F-theorem in 3d?

7) What are its potential applications?

8) Is there a higher-dimensional version of the boundary g-theorem?

9) Why does it seem so hard to prove monotonicity theorems given the universal nature of the RG?

## Questions from the Discussion "What is a Phase"

Led by Frank Verstraete and David Perez-Garcia