"The 20th century was the interaction of geometry and physics, and the 21st century is the interaction of number theory with physics." This intriguing insight comes from our recent discussion with Yang-Hui He from the London Institute of Mathematical Sciences.  Yang told us an amazing story about the flow of ideas between mathematics and physics, that involves some of the most celebrated achievements in the last century. Yang-Hui He (Photo Rajarshi Maiti – CC BY-SA 4.0) You can find out more about the ideas we discussed with Yang in this podcast in the accompanying articles String theory: A promise from physics and String theory: Convincing mathematics. And stay tuned for the second part of our conversation with Yang in the next episode! We were speaking to Yang about a research programme, Black holes: bridges between number theory and holographic quantum information, held at the Isaac Newton Institute for Mathematical Sciences  in Cambridge.  The programme  brought together a fascinating array of experts in black holes and quantum theory, with mathematicians and computer scientists. You can read more in our coverage of the programme here. This content was produced as part of our collaboration with the Isaac Newton Institute for Mathematical Sciences (INI) – you can find all the content from our collaboration here. The INI is an international research centre and our neighbour here on the University of Cambridge's maths campus. It attracts leading mathematical scientists from all over the world, and is open to all. Visit www.newton.ac.uk to find out more.