# Monte Carlo calculations of conformal dimensions of large charge operators. Invited talk at the program on Quantum Mechanical Systems at Large Charge. Simons Center for Geometry and Physics. August 26, 2019 - September 20, 2019

Invited Talk

Recently it was proposed that conformal dimensions of certain large charge operators satisfy a simple relation with unknown coefficients. In this talk we explain our efforts to test this proposal and compute the unkown coefficients using Monte Carlo calculations. We focus on CFTs that arise at the O(2) and O(4) Wilson-Fisher fixed points as test cases. Since traditional Monte Carlo methods suffer from a severe signal-to-noise ratio problem in the large charge sectors, we use worldline formulations. In the O(2) case we show that the proposed large charge expansion works very well even up to the smallest charge. In the O(4) case, the charged sectors are labeled by the two SU(2) representations $(j_L,j_R)$. Here we introduce and study a drastically simplified alternate model, which we refer to as a "qubit model". We find that the $(j,j)$ sector continues to show excellent agreement with the proposed large charge expansion, again up to small values of $j$. We also present preliminary results on the behavior of the subleading $(j,j-1)$ sector.

### Service Performed By

- Chandrasekharan, Shailesh Professor of Physics

### Date

- August 26, 2019 - September 20, 2019

### Service or Event Name

- Invited talk at the program on Quantum Mechanical Systems at Large Charge

### Host Organization

- Simons Center for Geometry and Physics

### Location or Venue

- Stony Brook, NY