# Learning M-theory: Gauge theory of membranes, brane intersections, and the self-dual string

I've been learning a lot about M-theory. It's such a broad topic that, when people ask me 'what is M-theory?', I continue to struggle to know where to start. Right now, much of my learning is textbook and I have more questions than answers. I naturally take the approach of first wanting as broad and …

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# Stringification as categorisation

In quantum field theory one is typically taught to use perturbation theory when the equations of motion for the fields are nonlinear and weakly interacting. For example, in $latex \phi^4 &fg=000000 &s=2$ theory one can use a formal series as described by Rosly and Selivanov [1]. Perturbative theory is about mastering series expansions. The basic …

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# Mathematical physics and M-theory: The study of higher structures

In recent posts we've begun to discuss some ideas at the foundation of the duality symmetric approach to M-theory. As we started to review in the last entry, one of the first goals is to formulate and study a general field theory in which T-duality is a manifest symmetry. It was discussed how this was …

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# M-theory, the duality symmetric string, and fundamental mathematical structure

In quantum gravity, there presently exists a tight web of hints as well as numerous plausibility arguments in support of the proposed existence of M-theory; however, a systematic formulation of the non-perturbative theory remains an open problem. Without a fundamental formulation of M-theory, all we have is a hypothetical theory of which splinters of clues …

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# Literature: Duality Symmetric String and the Doubled Formalism

When it comes to a T-duality invariant formulation of string theory, there are two primary actions that are useful to study as a point of entry. The first is Tseytlin's non-covariant action. It is found in his formulation of the duality symmetric string, which presents a stringy extension of the Floreanini-Jackiw Lagrangians for chiral fields. …

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# Notes on the Swampland (3): Testing the Weak Gravity Conjecture – Gauge Fields, Dp-branes, Type II Strings, and F-Theory-Heterotic Duality

The following collection of notes is based on a series of lectures that I attended by Eran Palti at SiftS 2019 at Universidad Autonoma de Madrid. The theme of the lecture series was ‘String Theory and the Swampland’. Palti’s five lectures were supported by his most recent and impressive 200 page review paper on the …

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# Notes on the Swampland (2): Weak Gravity Conjecture, Distance Conjecture, and the Parameter Space of M-theory

The following collection of notes is based on a series of lectures that I attended by Eran Palti at SiftS 2019 at Universidad Autonoma de Madrid. The theme of the lecture series was 'String Theory and the Swampland'. Palti's five lectures were supported by his most recent and impressive 200 page review paper on the …

Continue reading Notes on the Swampland (2): Weak Gravity Conjecture, Distance Conjecture, and the Parameter Space of M-theory