Joseph Polchinski

Joseph Polchinski was an American theoretical physicist who identified D-branes in string theory in 1995. This profound discovery revolutionized the field by providing a mathematical framework for understanding higher-dimensional objects in quantum gravity.

A D-brane is a theoretical surface within string theory upon which open strings must attach with their endpoints. Polchinski's identification of these structures allowed physicists to map the properties of black holes and dramatically advanced modern quantum gravity research.

The discovery of D-branes reshaped modern quantum gravity research by sparking the "second superstring revolution" in the mid-1990s. It allowed physicists to use string theory to calculate the entropy of specific black holes, solving a long-standing paradox in physics.

For most of his career, Joseph Polchinski worked as a prominent professor at the University of California, Santa Barbara (UCSB). He was a permanent member of the Kavli Institute for Theoretical Physics located on the UCSB campus when he published his D-brane research.