You’ve heard of cryptography. Perhaps quantum cryptography too. Maybe even post-quantum cryptography. But what about *quantum post-quantum cryptography*?! When this came up in conversation with Oxford Computer Scientist Matthew Gray recently, I’d never heard of it. I wanted to know more, so I invited him for a podcast. Turns out, there’s a whole world of layers to unravel linking quantum and cryptography — or even multiple worlds… In this discussion, we dip into those, and how this all relates to “metacomplexity” problems: the hardness of figuring out the hardness of a problem. Listen to this episode if you want to experience your perception of how quantum computing meets cryptography shift from monochrome to technicolour, as we push cryptography to its limits through the lens of fundamental assumptions about computation, quantum physics and reality.

What if time isn’t fundamental — but emerges from quantum mechanics itself? In this episode, Dr Simone Rijavec explains how a timeless quantum universe can still give rise to the illusion of time flowing. We unpack the Wheeler–DeWitt equation, the Page–Wootters model of relational time, and how these ideas connect to the multiverse and quantum gravity. Dr Rijavec is a postdoctoral researcher at Tel Aviv University and former PhD researcher at the University of Oxford.

From the Big Bang puzzles to testing if the early universe was quantum entangled — physicist Dr Aditya Iyer, from the University of Oxford, explains how quantum phenomena are key to understanding cosmology, gravity and even how it's possible we exist at all.