Joseph Polchinski (born May 16, 1954) is an American theoretical physicist and string theorist.
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings.
 It describes how these strings propagate through space and interact with each other.
 On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string.
 In string theory, one of the many vibrational states of the string corresponds to the graviton, a quantum mechanical particle that carries gravitational force.
 Thus string theory is a theory of quantum gravity.
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.
The method of image charges (also known as the method of images and method of mirror charges) is a basic problem-solving tool in electrostatics.
 The name originates from the replacement of certain elements in the original layout with imaginary charges, which replicates the boundary conditions of the problem (see Dirichlet boundary conditions or Neumann boundary conditions).
In physics, a string is a physical object that appears in string theory and related subjects.
 Unlike elementary particles, which are zero-dimensional or point-like by definition, strings are one-dimensional extended objects.
 A major reason for interest in string theories is that theories in which the fundamental objects are strings rather than point particles automatically have many properties that some physicists expect to hold in a fundamental theory of physics.
 Most notably, a theory of strings that evolve and interact according to the rules of quantum mechanics will automatically describe quantum gravity.
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.
The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next is a 2006 book by the theoretical physicist Lee Smolin about the problems with string theory.
 Subtitled "The Rise of String Theory, the Fall of a Science, and What Comes Next", the book strongly criticizes string theory and its prominence in contemporary theoretical physics, on the grounds that string theory has yet to come up with a single prediction that can be verified using any technology that is likely to be feasible within our lifetimes.
 Smolin also focuses on the difficulties faced by research in quantum gravity, and by current efforts to come up with a theory explaining all four fundamental interactions.
 The book is broadly concerned with the role of controversy and diversity of approaches in scientific processes and ethics.
In string theory, D-branes are a class of extended objects upon which open strings can end with Dirichlet boundary conditions, after which they are named.
 D-branes were discovered by Dai, Leigh and Polchinski, and independently by Hořava in 1989.
 In 1995, Polchinski identified D-branes with black p-brane solutions of supergravity, a discovery that triggered the Second Superstring Revolution and led to both holographic and M-theory dualities.
In theoretical physics, a string background refers to the set of classical values of quantum fields in spacetime that correspond to classical solutions of string theory.
 Such a background is associated with geometry that solves Einstein's equations (with higher order corrections) or their generalizations and with the values of other fields.
 These fields may encode the information about the shape of the hidden dimensions; the size of various electromagnetic fields and their generalizations; the values of fluxes; and the presence of additional objects such as D-branes and orientifold planes.
 The full physics of string theory can always be thought of as a system of infinitely many quantum fields expanded around a given string background.
In theoretical physics, boundary conformal field theory (BCFT) is a conformal field theory defined on a spacetime with a boundary (or boundaries).
 Different kinds of boundary conditions for the fields may be imposed on the fundamental fields; for example, Neumann boundary condition or Dirichlet boundary condition is acceptable for free bosonic fields.
 BCFT was developed by John Cardy.

Question: In string theory, D-branes are a class of extended objects upon which open strings can end with Dirichlet boundary conditions, after which they are named, D-branes were discovered by Dai, Leigh and which American theoretical physicist, and string theorist?
Answer: Joseph Polchinski