Non-supersymmetric Backgrounds Research Articles

D-terms in generalised complex geometry

Generalised Complex Geometry provides a natural interpretation of the N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetry conditions for warped solutions of type II supergravity as differential equations on polyforms on the internal manifold. Written in this language the supersymmetry conditions correspond to calibration conditions for probe D-branes: D-string, domain-wall or space-filling branes, depending on the directions they span in the non-compact four-dimensional space. The BPS condition corresponding to the calibration of space-filling D-branes has been reformulated by Tomasiello, eliminating the explicit dependence on the metric. We generalise this derivation to the case of non-supersymmetric backgrounds violating the domain-wall and D-string calibration conditions. We use this reformulation to derive constraints that the ten-dimensional solutions with BPS space-filling sources must respect in order to dimensionally reduce to solutions of four-dimensional N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supergravity with non-vanishing F-terms and potentially non-vanishing D-terms. We give the equations of motion for the class of type II vacua satisfying these constraints in the language of pure spinors. We investigate how restrictive these constraints are for the class of type IIB SU(3) backgrounds with BPS space-filling O5-planes.

Holographic evidence for nonsupersymmetric conformal manifolds

We provide the first holographic evidence for the existence of a nonsupersymmetric conformal manifold arising from exactly marginal but supersymmetry-breaking deformations of a superconformal three-dimensional field theory. In particular, we construct a 2-parameter nonsupersymmetric deformation of a supersymmetric AdS nongeometric background in type IIB string theory. We prove that the nonsupersymmetric backgrounds are perturbatively stable and also do not suffer from various nonperturbative instabilities. Finally, we argue that diffeomorphism symmetry protects our solutions against higher-derivative string corrections.

Non-supersymmetric AdS6 and the swampland

We discuss infinite families of non-supersymmetric AdS6 solutions in Type IIB string theory. They are siblings of supersymmetric solutions which are associated with (p, q) 5-brane webs and holographically dual to 5d SCFTs engineered by those brane webs. The non-supersymmetric backgrounds carry identical 5-brane charges and are connected to the supersymmetric ones by RG flows. We study the stability of the non-supersymmetric solutions, identifying perturbative and non-perturbative decay channels for all the backgrounds explicitly available. We also identify likely decay mechanisms for solutions that have not been constructed explicitly but may be expected to exist based on brane web considerations. Finally, we exclude scale separation by constructing universal spin 2 modes with masses comparable to the mass-scale of the cosmological constant.

Holographic entanglement entropy, subregion complexity and Fisher information metric of ‘black’ non-susy D3 brane

The BPS D3 brane has a non-supersymmetric cousin, called the non-susy D3 brane, which is also a solution of type IIB string theory. The corresponding counterpart of black D3 brane is the ‘black’ non-susy D3 brane and like the BPS D3 brane, it also has a decoupling limit, where the decoupled geometry (in the case we are interested, this is asymptotically AdS5 × S5) is the holographic dual of a non-conformal, non-supersymmetric QFT in (3+1)-dimensions. In this QFT we compute the entanglement entropy (EE), the complexity and the Fisher information metric holographically using the above mentioned geometry for spherical subsystems. The fidelity and the Fisher information metric have been calculated from the regularized extremal volume of the codimension one time slice of the bulk geometry using two different proposals in the literature. Although for AdS black hole both the proposals give identical results, the results differ for the non-supersymmetric background.

Supersymmetric and non-supersymmetric Seiberg-like dualities for gauged Wess–Zumino–Witten theories, realised on branes

In this work we extend the results of previous derivations of Seiberg-like dualities (level-rank duality) between gauged Wess–Zumino–Witten theories. The arguments in use to identify a potential dual for the supersymmetric WZW theory based on the coset U(N+M)kU(N)k can be extended to be applied to a wider variety of gauge groups, notably USp(2N+2M)2kUSp(2N)2k and SO(2N+2M)2kSO(2N)2k, which will be dealt with briefly. Most interestingly, non-supersymmetric versions of the latter theories can also be shown to have duals in a similar fashion. These results are supported by several pieces of evidence, string phenomenological interpretations of Seiberg duality, even in non-supersymmetric backgrounds, are helpful to justify the formulation, then, from field theory, quantities such as central charges or Witten indices are shown to match exactly. The stability of these non-supersymmetric models is also discussed and shown to be consistent.

The non-SUSY baryonic branch: soft supersymmetry breaking of $ \mathcal{N} = 1 $ gauge theories

We study a non-supersymmetric deformation of the field theory dual to the baryonic branch of Klebanov-Strassler. Using a combination of analytical (series expansions) and numerical methods we construct non-supersymmetric backgrounds that smoothly interpolate between the desired UV and IR behaviors. We calculate various observables of the field theory and propose a picture of soft breaking by gaugino masses that is consistent with the various calculations on the string side.

Nonsupersymmetric strong coupling background from the largeNquantum mechanics of two matrices coupled via a Yang-Mills interaction

We derive the planar large N non-supersymmetric background of the quantum mechanical hamiltonian of two hermitean matrices coupled via a Yang-Mills interaction, in terms of the density of eigenvalues of one of the matrices. This background satisfies an implicit non linear integral equation, with a perturbative small coupling expansion and a solvable large coupling solution, which is obtained. The energy of system and the expectation value of several correlators are obtained in this strong coupling limit. They are free of infrared divergences.

PP-WAVES ON SUPERBRANE BACKGROUNDS

In this paper we discuss a method of generating solutions of the Einstein equations on supersymmetric and non-supersymmetric backgrounds. The method involves the embedding of a supersymmetric spacetime into another, curved spacetime. We present three examples with constituent spacetimes which support "charges", one of which was known previously and the other two of which are new. All of the examples have PP-waves as one of the embedding constituents.

Non-supersymmetric deformations of non-critical superstrings

We study certain supersymmetry breaking deformations of linear dilaton backgrounds in different dimensions. In some cases, the deformed theory has bulk closed strings tachyons. In other cases there are no bulk tachyons, but there are localized tachyons. The real time condensation of these localized tachyons is described by an exactly solvable worldsheet CFT. We also find some stable, non-supersymmetric backgrounds.

Chiral symmetry breaking driven by dilaton

Dynamical properties of gauge theories with light flavor quarks are studied in a dual supergravity by adding a D7 brane probe into the AdS background deformed by the dilaton. By estimating the vev of flavor quark-bilinear in both the supersymmetric and non-supersymmetric gravity duals, we find spontaneous chiral symmetry breaking in the case of the non-supersymmetric background. We also study quark–antiquark potential for light quarks to see the quark confinement in the models considered here.

Chiral dynamics from AdS space

We study the low energy dynamics of pions in a gravity dual of chiral symmetry breaking. The string theory construction consists of a probe D7 brane in the Constable Myers non-supersymmetric background, which has been shown to describe chiral symmetry breaking in the pattern of QCD. We expand the D7 brane's Dirac Born Infeld action for fluctuations that correspond to the Goldstone mode and show that they take the form of a non-linear chiral lagrangian. We numerically compute the quark condensate, pion decay constant and higher order Gasser Leutwyler coefficients. We find their form is consistent with naive dimensional analysis estimates. We also explore the gauging of the quark's chiral symmetries and the vector meson spectrum.

Multi-spin string solutions in AdS black hole and confining backgrounds

We study semi-classical multi-spin strings in the non-supersymmetric backgrounds of AdS black hole and Witten's confining model. We consider constant radius strings with rotations along the isometries of the backgrounds. In the AdS black hole, solutions exist only if there is a non-zero spin in the black hole part. In contrast with the AdS background, we find solutions which although have no rotation in the S 5 part, have a regular λ expansion in the expression for large energy. In the near-extremal D 3 and D 4 backgrounds, we find that strings have to be located on the confining wall. We also discuss the stability of solutions by considering the fluctuation Lagrangians.

Analytic non-supersymmtric background dual of a confining gauge theory and the corresponding plane wave theory of Hadrons

We find a regular analytic 1st order deformation of the Klebanov-Strassler background. From the dual gauge theory point of view the deformation describes supersymmetry soft breaking gaugino mass terms. We calculate the difference in vacuum energies between the supersymmetric and the non-supersymmetric solutions and find that it matches the field theory prediction. We also discuss the breaking of the $U(1)_R$ symmetry and the space-time dependence of the gaugino bilinears two point function. Finally, we determine the Penrose limit of the non-supersymmetric background and write down the corresponding plane wave string theory. This string describes ``annulons''-heavy hadrons with mass proportional to large global charge. Surprisingly the string spectrum has two fermionic zero modes. This implies that the sector in the non-supersymmetric gauge theory which is the dual of the annulons is supersymmetric.

A note on orientifolds and dualities of type 0B string theory

We generalize the construction of four dimensional non-tachyonic orientifolds of type 0B string theory to non-supersymmetric backgrounds. We construct a four dimensional model containing self-dual D3 and D9-branes and leading to a chiral anomaly-free massless spectrum. Moreover, we discuss a further tachyon-free six dimensional model with only D5 branes. Eventually, we speculate about strong coupling dual models of the ten-dimensional orientifolds of type 0B.

Einstein spaces in five and seven dimensions and non-supersymmetric gauge theories

A one-parameter family of new solutions representing Einstein spaces in d=5,7 is presented, and used to construct non-supersymmetric backgrounds in type IIB and M-theory that asymptotically approach AdS 5× S 5 and AdS 7× S 4. Upon dimensional reduction, the latter gives a type IIA solution representing a 4-brane with Ramond-Ramond charge, which interpolates between the “near-horizon" non-extremal D4 brane and a geometry connected by T-duality to a new constant dilaton solution in type IIB. We discuss the possibility that M-theory on this space may be related to a (0,2) six-dimensional field theory on S 1× S 1, with fermions obeying antiperiodic boundary conditions in both circles.

Supersymmetry and dualities

Duality transformations with respect to rotational isometries relate supersymmetric with non-supersymmetric backgrounds in string theory. We find that non-local world-sheet effects have to be taken into account in order to restore supersymmetry at the string level. The underlying superconformal algebra remains the same, but in this case T-duality relates local with non-local realizations of the algebra in terms of parafermions. This is another example where stringy effects resolve paradoxes of the effective field theory. (Contribution to the proceedings of the Trieste conference on S-Duality and Mirror Symmetry; to appear in Nucl Phys B Proc Suppl)