Why do we care about quantum information?

I’ve been enjoying the weekly colliquium talks on offer this semester at CUNY. While the attendance is usually small, a couple of weeks ago we were lucky to get to have a talk from Leonard Susskind, one of the most influential theoretical physicists of the last 50 years.

The talk was structured as a fairly interactive Q&A, but begun with a brief introduction to complexity, with a focus on black holes and the holographic principle, including a nice discussion of the “ER=EPR” conjecture and an anecdote of the origins of the holographic principle.

I’ve never taken a string theory course, and my one semester of general relativity felt inadequate to capture the full depth of the ideas at play but it was still a fascinating talk. The distinction made between capital S String theory and string theory as a tool for understanding quantum gravity was interesting, especially given recent criticism from within and beyond the physics community.

I’m tremendously grateful for the opportunity to ask questions and engage with the speaker as well as Prof. Dan Kabat at CUNY who works on similar topics, and I was shocked to be invited to follow up personally via email regarding my question on entanglement between static spacetime patches. All in all it was a great reminder of the breadth and depth of quantum information theory as a field, and the many different ways it can be applied to understand the world around us.

What I’m Taking Away

Quantum computers are exciting. Applications of quantum information to cryptography, technology and metrology are cool and there is no shortage of commercial hype. I certainly won’t forget now that quantum information theory is much more than just a tool for building quantum computers. It is a powerful lens for understanding the fundamental nature of reality, and the deep connections between information, physics, and spacetime that are still being uncovered. It seems difficult to imagine a universe without information, so even if quantum computers never reach their full potential, the study of quantum information will continue to be a rich and rewarding field of research for decades to come.