In the context of quantum gravity and string theory, the presence of infinities in calculations poses significant challenges. These infinities arise in certain calculations when attempting to describe the behavior of particles and fields in the framework of quantum mechanics and general relativity. They signal that the theory is encountering mathematical inconsistencies and breakdowns, preventing straightforward calculations and predictions.
The study of these infinities has motivated the development of various techniques and approaches aimed at resolving them. Some of these techniques include regularization and renormalization methods, which allow physicists to manipulate and remove the infinities from calculations, yielding finite and meaningful results. These methods have been successful in specific cases, such as quantum electrodynamics, but face greater challenges when applied to quantum gravity and string theory due to the complexities of these theories.
AdS/CFT correspondence, also known as the gauge/gravity duality, proposed by Juan Maldacena, is a significant development in string theory that provides a mathematical equivalence between certain string theory models in a curved spacetime (Anti-de Sitter, AdS) and conformal field theories (CFT) without gravity. This duality has shed light on the behavior of strongly interacting quantum systems and has been a fruitful area of research.
Joseph Polchinski, another prominent physicist, made important contributions to string theory, particularly in the study of D-branes and their role in string dynamics.
Regarding the issue of infinities in quantum gravity and string theory calculations, different physicists may have different perspectives, and there may not be a complete consensus. The resolution of infinities in these contexts is an active area of research, and multiple approaches and ideas are being explored.
Physicists like Maldacena and Polchinski have made significant contributions to our understanding of these subjects, but they may have different viewpoints or emphasize different aspects of the field. It's important to note that the field of theoretical physics is dynamic and evolving, and new insights and perspectives continue to emerge over time as researchers delve deeper into these fundamental questions.