Pondering the Bits That Build Space-Time and Brains

An interview with Vijay Balasubramanian, past Member (2007–08) in the School of Natural Sciences:

"As theorists study black holes and other objects in AdS space, they keep learning Wheeler-esque lessons. One is that the connectivity of space — the ability to get from one place to another — seems to stem from particles on the boundary linked by correlations known as quantum entanglement. If one particle is pointing up, for instance, this tells you its entangled partner points down. This kind of information-sharing on the boundary of AdS space appears to enable the voluminous structure of the interior.

Vijay Balasubramanian of the University of Pennsylvania is one of the physicists working to translate Wheeler’s lofty ideas into crisp mathematics. The research he and his colleagues engage in now goes by the slogan 'it from qubit,' since quantum bits, or qubits — complex combinations of 0s and 1s — are more general than classical bits. In 1999, Balasubramanian worked out how to calculate mass and energy in AdS universes in terms of information about particles on the boundary. Since then, he has made fundamental contributions to theories of black holes and quantum gravity by studying the information content of various systems."