Author: Marika Taylor, Pro-vice-chancellor, Professor, University of Birmingham In 1980, Stephen Hawking gave his first lecture as Lucasian Professor at the University of Cambridge. The lecture was called “Is the end in sight for theoretical physics?” Hawking, who later became my PhD supervisor, predicted that a theory of everything – uniting the clashing branches of […]
The concept of moduli space is of utmost relevance in theoretical physics and mathematics, especially in geometry, topology and string theory. A moduli space is, roughly speaking, a space that classifies a given class of objects modulo an equivalence relation # which identifies the objects in that we want to consider as equivalent or, more […]
The purpose of this note is to introduce the reader to the notion of Lipschitz structure and its potential applications to the spin geometry required to globally formulate string theory and supergravity on a differentiable manifold. Spinors are a crucial ingredient in the global formulation of string/M-Theory and its low energy limit supergravity, since these […]
This is the second of the series of articles on the geometry of String Theory compactifications. Before reading this note, the interested reader may want to read the first note, where the concept of compactification background is introduced in the context of String Theory and M-Theory compactifications. As it is well known, to be well-defined […]
This is first of a series of notes on the geometry of String Theory compactifications. The space-time in String Theory is often described by means of a mathematical object called manifold . Manifolds are very important objects from the mathematical and the physics point of view, not only in String Theory. For example, differential geometry […]
In the previous articles (I, II), we have characterized the simplest class of supersymmetric heterotic compactification backgrounds. In particular, we have finished the second article with the following result: There is a class of admissible Heterotic internal manifolds characterized as being six-dimensional, oriented, spin, Riemannian compact manifolds admitting a parallel spinor respect to the Levi-Civita […]
One of hottest topics in theoretical physics today is, of course, quantum gravity. The fact that, almost a hundred years after the born of the quantum theory, we still not have a functional theory that describes gravity at a microscopic level has become one of the most attractive problems for the majority of physicists (even […]
Galaxies rotate faster than the matter we can see should allow. Evidence for an unseen, gravitating substance began to build in the 1930s with Fritz Zwicky’s studies of galaxy clusters, and strengthened in the 1970s as Vera Rubin measured how stars orbit within spiral galaxies. Nearly a century later, dark matter is still known almost […]
Somewhere between the microscopic realm of elementary particles and the macroscopic world of human beings, something strange happens: The rules of quantum physics, which work so exquisitely for tiny atoms, seem to lose their grip as objects grow larger. Pondering where and how this shift from small-scale quantum fuzziness to everyday sharp certainty happens gives […]
We’re often told it is “unscientific” or “meaningless” to ask what happened before the Big Bang. But a new paper by cosmologist Eugene Lim, of King’s College London, UK, and astrophysicists Katy Clough, of Queen Mary University of London, UK, and Josu Aurrekoetxea, at Oxford University, UK, proposes a way forward: using complex computer simulations […]