#
nLab

D1-brane

### Context

#### String theory

### Ingredients

### Critical string models

### Extended objects

### Topological strings

## Backgrounds

## Phenomenology

# Contents

## Idea

The D-brane of dimension $1+1$ in type IIB string theory. Also called the **D-string**, to be distinguished from the *fundamental* string.

## Properties

### S-duality with the fundamental string

Under S-duality the D1-brane mixes with the fundamental string to form the (p,q)-string.

A formalization of this in terms of the homotopy theory of the super L-infinity algebras which constitute the respective extended super spacetimes is in (FSS 13).

### Black hole entropy

At low string coupling D1-D5 brane bound states are described by 2d CFT, which is well understood. After passage to the corresponding strongly coupled black brane configurations in type IIB supergravity, which are black holes in the given compactification, the entropy of these 2d CFTs matches the Bekenstein-Hawking entropy of these black holes. See at *black holes in string theory* for more on this.

This is parts of the AdS/CFT correspondence. See (AGMOO, chapter 5).

**Table of branes appearing in supergravity/string theory** (for classification see at *brane scan*).

brane | in supergravity | charged under gauge field | has worldvolume theory |
---|

**black brane** | supergravity | higher gauge field | SCFT |

**D-brane** | type II | RR-field | super Yang-Mills theory |

**$(D = 2n)$** | type IIA | $\,$ | $\,$ |

D0-brane | $\,$ | $\,$ | BFSS matrix model |

D2-brane | $\,$ | $\,$ | $\,$ |

D4-brane | $\,$ | $\,$ | D=5 super Yang-Mills theory with Khovanov homology observables |

D6-brane | $\,$ | $\,$ | |

D8-brane | $\,$ | $\,$ | |

**$(D = 2n+1)$** | type IIB | $\,$ | $\,$ |

D(-1)-brane | $\,$ | $\,$ | $\,$ |

D1-brane | $\,$ | $\,$ | 2d CFT with BH entropy |

D3-brane | $\,$ | $\,$ | N=4 D=4 super Yang-Mills theory |

D5-brane | $\,$ | $\,$ | $\,$ |

D7-brane | $\,$ | $\,$ | $\,$ |

D9-brane | $\,$ | $\,$ | $\,$ |

(p,q)-string | $\,$ | $\,$ | $\,$ |

(D25-brane) | (bosonic string theory) | | |

**NS-brane** | type I, II, heterotic | circle n-connection | $\,$ |

string | $\,$ | B2-field | 2d SCFT |

NS5-brane | $\,$ | B6-field | little string theory |

**D-brane for topological string** | | | $\,$ |

A-brane | | | $\,$ |

B-brane | | | $\,$ |

**M-brane** | 11D SuGra/M-theory | circle n-connection | $\,$ |

M2-brane | $\,$ | C3-field | ABJM theory, BLG model |

M5-brane | $\,$ | C6-field | 6d (2,0)-superconformal QFT |

M9-brane/O9-plane | | | heterotic string theory |

M-wave | | | |

topological M2-brane | topological M-theory | C3-field on G2-manifold | |

topological M5-brane | $\,$ | C6-field on G2-manifold | |

**solitons** on M5-brane | 6d (2,0)-superconformal QFT | | |

self-dual string | | self-dual B-field | |

3-brane in 6d | | | |

## References

Chapter 5.3 of

Formulation of the S-duality with the fundamental string in terms of the homotopy theory of super L-infinity algebras of the respective extended super spacetimes is in section 4.3 of