string-theory

On the Schwinger effect seen in open string theory: On adjustments of the action functional for spin massive -particles (Rarita-Schwinger field) by non-minimal coupling that evades the Velo-Zwanziger problem: Discussion of the Velo-Zwanziger problem for the higher string excitations that appear in string theory: On supergravity models of cosmic inflation:

superalgebra and (synthetic ) supergeometry The Green-Schwarz action functional is an action functional for a sigma-model that describes the propagation of a fundamental super -brane in a super spacetime supermanifold. For this is the Green-Schwarz superparticle. For this is the Green-Schwarz superstring (Green-Schwarz 84) For this is the Green-Schwarz supermembrane (Bergshoeff-Sezgin-Townsend 87…

The D-brane of dimension in type IIA string theory. The worldline theory of a collection of D0-branes is supposed to be described by the BFSS matrix model. The non-perturbative limit of type IIA superstring theory is supposed to be M-theory compactified on a circle. The degree-2 RR-field that the D0-brane is charged under, with local potential 1-form may be understood as the KK-field induced by t…

general mechanisms electric-magnetic duality, Montonen-Olive duality, geometric Langlands duality string-fivebrane duality string-QFT duality QFT-QFT duality: effective QFT incarnations of open/closed string duality, relating (super-)gravity to (super-)Yang-Mills theory: Seiberg duality (swapping NS5-branes) Classical groups Finite groups Group schemes Topological groups Lie groups Super-Lie grou…

The BFSS matrix model (Banks-Fischler-Shenker-Susskind 96, Seiberg 97) is the description of the worldline dynamics of interacting D0-branes. In the large N limit of a large number of D0-branes this is supposed to encode the strong coupling limit of type IIA string theory known as M-theory at least in certain corners of its moduli space. The BFSS model is a limiting case of the BMN matrix model, …

On the maximal compact subalgebras of E9 and E10, respectively, and their finite-dimensional linear representations: Relating the E10 U-duality covariant sigma-model description of, hypothetically, M-theory to D=3 gauged supergravity: On tensor hierarchies in gauged supergravity: On relation of Borcherds algebras to tensor hierarchies in gauged supergravity: Jakob Palmkvist, Tensor hierarchies, B…

On the action of the modular group on spin structures over closed surfaces in relation to theta functions and string amplitudes: On the canonical/geometric quantization of D=3 Chern-Simons theory: Early argument that the RR-field flux density-expressions for D-brane charge are of the form of Chern characters on topological K-theory, leading to the K-theory classification of D-brane charge: Michae…

Relation of Niemeier lattices to heterotic string theory: On D-branes in type 0 string theory: On S-duality in 9D supergravity: On heterotic M-theory on ADE-orbifolds: Michael Faux, Dieter Lüst, Burt Ovrut, Intersecting Orbifold Planes and Local Anomaly Cancellation in M-Theory, Nucl. Phys. B554: 437-483, 1999 (arXiv:hep-th/9903028) Michael Faux, Dieter Lüst, Burt Ovrut, Local Anomaly Cancellatio…

On the Wess-Zumino-Witten model: On D8-branes as black branes in massive type IIA string theory: On S-duality in 9D supergravity: On pp-wave Penrose limits of homogeneous spacetimes: On black holes and black strings in D=5 supergravity:

Tomás Ortín On double dimensional reduction of the M5-brane to the D4-brane: On massive type IIA string theory and its embedding in M-theory via M9-branes: On D8-branes as black branes in massive type IIA string theory: On S-duality in 9D supergravity: Formulation of (Lagrangian densities for) type II supergravity with “democratic”/“pregeometric” RR-fields subject to self-duality: On D9-branes: O…

String Theory is considered a strong candidate for a “Theory of Everything” because it tries to explain all particles and forces, including gravity, using one basic idea: tiny vibrating strings. Different vibrations create different particles, and the theory naturally includes gravity, which is something current quantum theories struggle to do. Scientists also like string theory because its mathe…

A new study just added an interesting twist to the complicated history of the physics theory.

This entry is about a D-brane species in string theory. For the items in the ADE-classification of name D4, see there. The D-brane of dimension in type IIA string theory. Khovanov homology has long been expected to appear as the observables in a 4-dimensional TQFT in higher analogy of how the Jones polynomial arises as an observable in 3-dimensional Chern-Simons theory. For instance for a cobordi…

Cumrun Vafa is a string theorist at Harvard. On the action of the modular group on spin structures over closed surfaces in relation to theta functions and string amplitudes: Introducing what came to be called the Brandenberger-Vafa mechanism in string theoretic cosmology: On the quantum cohomology induced by supersymmetric sigma-models: Sergio Cecotti, Cumrun Vafa, Exact Results for Supersymmetri…

Physicists may have uncovered a surprising new clue that string theory—the idea that the universe is built from unimaginably tiny vibrating strings—could be more than just a mathematical fantasy. Instead of assuming strings existed from the start, researchers began with a few simple rules about how particles behave at extreme energies and discovered that the equations naturally produced the tellt…

general mechanisms electric-magnetic duality, Montonen-Olive duality, geometric Langlands duality string-fivebrane duality string-QFT duality QFT-QFT duality: effective QFT incarnations of open/closed string duality, relating (super-)gravity to (super-)Yang-Mills theory: Seiberg duality (swapping NS5-branes) What is called the mysterious duality in Vafa 00, Iqbal-Neitzke-Vafa 01 is a kind of “dua…

This review demonstrates that the framework proposed in ``Strings from Almost Nothing'' does not establish genuine foundational uniqueness, but merely reconstructs a heavily constrained bootstrap sector after imposing strongly string-compatible assumptions from the outset. The central claim of the paper, namely that string theory emerges ``inevitably'' from a small set of assumptions, is shown to…

In the context of string theory the NS5-brane is a certain extended physical objects – a brane – that appears in/is predicted by the theory. There are different incarnations of this object: For instance the effective background QFT of the type II string – type II supergravity – admits solutions to its generalized Einstein equations which describe higher dimensional analogs of charged black holes …

A bound state/brane intersection of D0-branes with D2-branes. Special case of Dp-D(p+2) brane bound states. What is called the Myers effect (Myers 99) in string theory is the claimed phenomenon that given D0-branes in a constant background RR field (the field strength associated with D2-brane charge) with, crucially, nonabelian effects included, then these D0-branes expand into a fuzzy 2-sphere w…

Fernando Quevedo is director of ICTP and now professor of physics at NYU Abu Dhabi. He works on (string theoretic) high energy physics phenomenology. institute page (NYU Abu Dhabi) institute page (Cambridge) Early discussion of nonabelian T-duality: On bottom-up model building for intersecting D-brane models: On moduli stabilization in string theory KK-compactifications (on Calabi-Yau manifolds):…