Closed strings from SO(8) Yang–Mills instantons (original) (raw)

Gauge instantons from open strings

Fortschritte der Physik, 2004

In this contribution we describe how to obtain instanton effects in four dimensional gauge theories by computing string scattering amplitudes in D3/D(−1) brane systems. In particular we show that the disks with mixed boundary conditions, which are typical of the D3/D(−1) system, are the sources for the classical instanton solution.

Classical gauge instantons from open strings

Journal of High Energy Physics, 2003

We study the D3/D(−1) brane system and show how to compute instanton corrections to correlation functions of gauge theories in four dimensions using open string techniques. In particular we show that the disks with mixed boundary conditions that are typical of the D3/D(−1) system are the sources for the classical instanton solution. This can then be recovered from simple calculations of open string scattering amplitudes in the presence of D-instantons. Exploiting this fact we also relate this stringy description to the standard instanton calculus of field theory.

E-strings and N = 4 topological Yang-Mills theories

Nuclear Physics B, 1998

We study certain properties of six-dimensional tensionless E-strings (arising from zero size E 8 instantons). In particular we show that n E-strings form a bound string which carries an E 8 level n current algebra as well as a left-over conformal system with c = 12n − 4 − 248n n+30 , whose characters can be computed. Moreover we show that the characters of the n-string bound state are captured by N = 4 U (n) topological Yang-Mills theory on 1 2 K3. This relation not only illuminates certain aspects of E-strings but can also be used to shed light on the properties of N = 4 topological Yang-Mills theories on manifolds with b + 2 = 1. In particular the E-string partition functions, which can be computed using local mirror symmetry on a Calabi-Yau threefold , give the Euler characteristics of the Yang-Mills instanton moduli space on 1 2 K3. Moreover, the partition functions are determined by a gap condition combined with a simple recurrence relation which has its origins in a holomorphic anomaly that has been conjectured to exist for N = 4 topological Yang-Mills on manifolds with b + 2 = 1 and is also related to the holomorphic anomaly for higher genus topological strings on Calabi-Yau threefolds.

Effects of D-instantons in string amplitudes

Physics Letters B, 2005

We investigate the different energy regimes in the conjectured SL(2, Z) invariant four graviton scattering amplitude that incorporates D-instanton contributions in 10d type IIB superstring theory. We show that the infinite product over SL(2, Z) rotations is convergent in the whole complex plane s, t. For high energies α ′ s ≫ 1, fixed scattering angle, and very weak coupling g s ≪ 1/(α ′ s), the four-graviton amplitude exhibits the usual exponential suppression. As the energy approaches 1/g s , the suppression gradually diminishes until there appears a strong amplification near a new pole coming from the exchange of a (p, q) string. At energies α ′ s ≪ 1/ √ g s , the pure D instanton contribution to the scattering amplitude is found to produce a factor A Dinst 4 ∼ = exp(cg 3/2 s e − 2π g s s 3). At energies 1/ √ g s ≪ α ′ s ≪ 1/g s , the D-instanton factor becomes A Dinst 4 ∼ = exp(2e − 2π g s +πg s s 2), α ′ = 4. At higher energies α ′ s ≫ 1/g s the D-instanton contribution becomes very important, and one finds an oscillatory behavior which alternates suppression and amplification. This suggests that non-perturbative effects can lead to a high-energy behavior which is significantly different from the perturbative string behavior.

Fortschritte der Physik Stringy instantons and dualities

2016

We discuss non-perturbative corrections to the gauge kinetic functions in a four-dimensional N = 2 gauge theory realized with a system of D7/D3-branes in a compactification of type I ′ theory on T4/Z2 × Z2. The non-perturbative contributions arise when D(-1) branes, corresponding to stringy instantons, are added to the system; such contributions can be explicitly evaluated using localization techniques and precisely match the results predicted by the heterotic/type I ′ duality. This agreement represents a very non-trivial test of the stringy multi-instanton calculus.

On the perturbative corrections around D-string instantons

Journal of High Energy Physics, 1999

We study F 4-threshold corrections in an eight dimensional S-dual pair of string theories, as a prototype of dual string vacua with sixteen supercharges. We show that the orbifold CFT description of D-string instantons gives rise to a perturbative expansion similar to the one appearing on the fundamental string side. By an explicit calculation, using the Nambu-Goto action in the static gauge, we show that the first subleading term agrees precisely on the two sides. We then give a general argument to show that the agreement extends to all orders.

Extended self-dual Yang-Mills from the N = 2 string

Nuclear Physics B, 1998

We show that the physical degrees of freedom of the critical open string with N =2 superconformal symmetry on the worldsheet are described by a self-dual Yang-Mills field on a hyperspace parametrised by the coordinates of the target space R 2,2 together with a commuting chiral spinor. A prepotential for the self-dual connection in the hyperspace generates the infinite tower of physical fields corresponding to the inequivalent pictures or spinor ghost vacua of this string. An action is presented for this tower, which describes consistent interactions amongst fields of arbitrarily high spin. An interesting truncation to a theory of five fields is seen to have no graphs of two or more loops. * supported in part by the 'Deutsche Forschungsgemeinschaft'; grant LE-838/5-1

SO(3)×U(1) Isometric Instantons with Non-Abelian Hair in Four-Dimensional String Theory

Modern Physics Letters A, 1997

We compute the exact effective string vacuum backgrounds of the level k=81/19 SU(2,1)/U(1) coset model. A compact SU(2) isometry present in this seven-dimensional solution allows one to interpret it after compactification as a four-dimensional non-Abelian SU(2) charged instanton with a singular submanifold and an SO(3) × U(1) isometry. The semiclassical backgrounds, solutions of the type II strings, present similar characteristics

Instanton String and M-Wave in Multiple M4-branes system

2013

We consider the non-abelian self-dual two-form theory [1] and find new exact solutions. Our solutions are supported by Yang-Mills (anti)instantons in 4-dimensions and describe wave moving in null directions. We argue and provide evidence that these instanton string solutions correspond to M-wave (MW) on the worldvolume of multiple M5-branes. When dimensionally reduced on a circle, the MW/M5 system is reduced to the D0/D4 system with the D0-branes represented by the Yang-Mills instanton of the D4-branes Yang-Mills gauge theory. We show that this picture is precisely reproduced by the dimensional reduction of our instanton string solutions.

String Theory and ALE Instantons

Arxiv preprint hep-th/ …, 1994

We show that the classical equations of motion of the low-energy effective field theory describing the massless modes of the heterotic (or type I) string admit two classes of supersymmetric self-dual backgrounds. The first class, which was already considered in the literature, consists of solutions with a (conformally) flat metric coupled to axionic instantons. The second includes Asymptotically Locally Euclidean (ALE) gravitational instantonic backgrounds coupled to gauge instantons through the so-called "standard embedding".