## Computing Resources

Below is basic information for the three computing lab courses. Each of these will be held in one of Bard's computing labs and all the software you need will be installed before you arrive at the school. However, you are welcome, and even encouraged, to work on your own laptop computer.Except for Mathematica, all the software used in the computing labs is free and available online. Brief instructions explaining how to access and begin the installation process for this software is included for Labs B & C in their respective sections. Bard has a site license for Mathematica that you will be able to use in the campus computer labs.

All three lab sections have a Lab 0 that you can download here and use to check your installations and/or become familiar with the basics of the computing language leading up to the school. If you are in Lab A and do not already have access to Mathematica, you can wait until you arrive at Bard to do Lab 0; this is not a problem.

**Lab A**: Numerical Methods in LQG with Pietro Doná—Albee (ALB) 100

If you have access to Mathematica install it. If not, you can use the computers at Bard.

**Lab 3:**NumericalMethodsForLQG_Lab3.nb- Kit for building the Regge calculus demonstration
- Classic reference on the asymptotics of the 6j-symbol: Ponzano & Regge
**Lab 2:**NumericalMethodsForLQG_Lab2.nb**Lab 1:**NumericalMethodsForLQG_Lab1.nb**Lab 0:**NumericalMethodsForLQG_Preliminary.nb

**Lab B**: Tensor Network Renormalization with Sebastian Steinhaus—Henderson (HDR) 106

**Lab 3:**TNR Ising Model - Simple implementation of algorithm (only 2 singular values): TensorNetworkRenormalization-IsingModel.ipynb- TNR Ising Model more SVs - Maximum number of singular values can be set in algorithm (careful, setting this number too high slows down algorithm tremendously)TensorNetworkRenormalization-IsingModel-moreSVs.ipynb.
- TNR Ising Model symmetry - Explicit preservation and using of the global Z_2 symmetry (we explicitly preserve the Z_2 delta function / Gauss constraint on the vertices, but only keep two singular values)TensorNetworkRenormalization-IsingModel-Symmetry.ipynb
**Lab 1:**TensorNetworkRenormalization-IsingModel-blank.ipynb- Installation instructions for Julia, IJulia, Plots, and Jupyter: SteinhausInstallationInstructions.pdf.
**Lab 0:**Testing-Julia.ipynb. (May require CTL click to download. Also, annoyingly, some browsers, e.g. Safari, may default the downloaded file to .txt format. To fix this you have to go to a Terminal and use mv, or a similar command, to rename the file; renaming the file using the icon usually won't work.)**References:**Levin & Nave arXiv:0611687

Bahr, Dittrich, & Ryan arXiv:1103.6264

**Lab C**: The Cosmic Microwave Background with Boris Bolliet—Reem-Kayden Center (RKC) 100

**Lab 3:**Bolliet-bard-lab-3.zip**Lab 2 Notes:**Bolliet-bard-school-lab2.pdf.**Lab 2:**primordial_pk_bounce_over_primordial_pk_sr.txt.**Lab 1 Notes:**Bolliet-bard-school-lab1.pdf.**Lab 1:**bard-notebook-lab-1.ipynb. (May require CTL click to download. Also, annoyingly, some browsers, e.g. Safari, may default the downloaded file to .txt format. To fix this you have to go to a Terminal and use mv, or a similar command, to rename the file; renaming the file using the icon usually won't work.)- You will want to install Jupyter notebooks, class, and Montepython. Instructions for installations can be found in the README files or on the webpages. If you want to have a look and start playing with these pieces of software it would be good, but not crucial. I will go over everything with you, from scratch.
- More importantly, if you have some time before the school it would be great to read to these three papers:

Ma and Bertschinger

Seljak and Zaldarriaga

Julien Lesgourgues

The first two papers are the "foundation" papers of modern CMB computations, and the third is a very good review.

## Videos

### The Story of Loop Quantum Gravity - From the Big Bounce to Black Holes

A video by Phil and Monica Halper (May 2019)What happens at the centre black holes? What happened before the big bang? A quantum theory of gravity is needed to answer these questions . Many of the leading scientists who developed Loop Quantum Gravity, one of the most promising attempts, tell the story of how it was developed in this film. We also go on to explore how the theory may be tested via observations of black holes or probing the very early universe. We interview Abhay Ashtekar, AurĂ©lien Barrau, Sir Roger Penrose, Lee Smolin, Carlo Rovelli, and Francesca Vidotto. The film tackles some of the biggest questions of existence.

After the school, we will post videos of the shool lectures here according to the approval of the lecturer.