When was the American theoretical physicist and cosmologist which Alexander Vilenkin worked with in 2013 born
Alan Guth Alan Harvey Guth ( ; born February 27, 1947) is an American theoretical physicist and cosmologist. Guth has researched elementary particle theory (and how particle theory is applicable to the early universe). He is currently serving as Victor Weisskopf Professor of Physics at the Massachusetts Institute of Technology. Along with Alexei Starobinsky and Andrei Linde, he won the 2014 Kavli Prize “for pioneering the theory of cosmic inflation.”
James Sethian James Albert Sethian (born 10 May 1954) is a professor of mathematics at the University of California, Berkeley, and the head of the Mathematics Group  at the United States Department of Energy's Lawrence Berkeley National Laboratory.