Question: Name the American theoretical physicist, mathematician, and string theorist who has been professor at Columbia University since 1996 and who wrote the book 'The Hidden Reality' which explores the concept of the multiverse?
Context: Joseph Polchinski (born May 16, 1954) is an American theoretical physicist and string theorist. Tasneem Zehra Husain (also spelled as Tasneem Zehra Hussain), is a Pakistani theoretical physicist and an Assistant Professor of Physics at the Lahore University of Management Sciences.  She is one of the few Pakistani women to obtain a doctorate in physics, and the first Pakistani woman string theorist.  An eminent scientist, she has been a guest speaker at a various schools and colleges in an effort to promote science and technology in Pakistan. Brian Randolph Greene (born February 9, 1963) is an American theoretical physicist, mathematician, and string theorist.  He has been a professor at Columbia University since 1996 and chairman of the World Science Festival since co-founding it in 2008.  Greene has worked on mirror symmetry, relating two different Calabi–Yau manifolds (concretely, relating the conifold to one of its orbifolds).  He also described the flop transition, a mild form of topology change, showing that topology in string theory can change at the conifold point. Herman Louis Verlinde (born 21 January 1962) is a Dutch theoretical physicist and string theorist.  He is a professor at Princeton University.  He is also the identical twin brother of Erik Verlinde. Arvind Rajaraman is an Indian-born theoretical physicist and string theorist.  Rajaraman earned his Ph.D. from Stanford University.  He is an associate professor at University of California, Irvine. The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos is a book by Brian Greene published in 2011 which explores the concept of the multiverse and the possibility of parallel universes.  It has been nominated for the Royal Society Winton Prize for Science Books for 2012. Barcelona's Multiverse is a book and a term based on the possibility of another Barcelona in a universe not visible from ours.  With the title of the book in English "Barcelona's Multiverse", the author Lluís Bussé (Barcelona, 1961) takes the photomontages of various emblematic locations of Barcelona, with the intention of showing the existence of another Barcelona whose laws and physical constants would be similar to ours.  It is based on the theories of theoretical physicist, Max Tegmark (MIT) in the Multiverse Level I.  The exhibition of photographs from the book was held in the Palau Robert in Barcelona (from 21 June to 11 September 2012). David Jonathan Gross ( ; born February 19, 1941) is an American theoretical physicist and string theorist.  Along with Frank Wilczek and David Politzer, he was awarded the 2004 Nobel Prize in Physics for their discovery of asymptotic freedom.  David Gross is the Chancellor’s Chair Professor of Theoretical Physics at the Kavli Institute for Theoretical Physics of the University of California, Santa Barbara, and was formerly the KITP director and holder of their Frederick W. Gluck Chair in Theoretical Physics .  He is also a faculty member in the UC Santa Barbara Physics Department and is currently affiliated with the Institute for Quantum Studies at Chapman University in California.  He is a foreign member of the Chinese Academy of Sciences. Shiraz Naval Minwalla is an Indian theoretical physicist and string theorist.  He is a faculty member in the Department of Theoretical Physics at Tata Institute of Fundamental Research, Mumbai.  Prior to his present position, he was a Harvard Junior Fellow and subsequently an Assistant Professor at Harvard University. Erik Peter Verlinde (] ; born 21 January 1962) is a Dutch theoretical physicist and string theorist.  He is the identical twin brother of physicist Herman Verlinde.  The Verlinde formula, which is important in conformal field theory and topological field theory, is named after him.  His research deals with string theory, gravity, black holes and cosmology.  Currently, he works at the Institute for Theoretical Physics at the University of Amsterdam.
Answer: Brian Greene