Anti-de Sitter BPS black holes in N=2 gauged supergravity

Electrically charged solutions breaking half of the supersymmetry in Anti-de Sitter four dimensional N=2 supergravity coupled to vector supermultiplets are constructed. These static black holes live in an asymptotic AdS₄ space time. The Killing spinor, i.e., the spinor for supersymmetry variation is explicitly constructed for these solutions.     

Nonlinear supersymmetry without the GSO projection and unstable D9-brane

Orientable open string theories containing both bosons and fermions without the GSO projection are expected to have the 10-dimensional N=2 space–time supersymmetry in a spontaneously broken phase. We study the low-energy theorem for the nonlinearly realized N=2 supersymmetry using the effective action for an unstable D9-brane. It is explicitly confirmed that the 4-fermion open string amplitudes without the GSO projection obey the low-energy theorem derived from the nonlinear N=2 supersymmetry. An intimate connection between the existence of the hidden supersymmetry and the open–open string (s–t) duality is pointed out.     

On a hydrodynamical description of the Dirac equation

A new form of the Dirac equation in curved spacetime (M, g) is given. It is based on the representation of a bispinor by means of an orthonormal vierbein e_α and a complex number ?. In the geometrical language the Dirac equation obtained this way is equivalent to the system of second order equations for the vierbein. The function ? is uniquely determined by the vierbein field.     

The one-loop N = 2 supercurrent anomaly

A one-loop superspace calculation of the N = 2 supercurrent anomaly is performed. The method preserves explicitly both N = 2 supersymmetry and gauge invariance.     

Two-loop vacuum amplitude in four-dimensional heterotic string models

The two-loop measure of four-dimensional heterotic strings with N=4, 2 and 1 space-time supersymmetry is explicitly calculated. It is shown that the cosmological constants of these models at two loops are zero.     

Grand unification with local supersymmetry

We study general conditions for obtaining spontaneous breaking of local supersymmetry in N = 1 supergravity coupled to supersymmetric matter. We consider in particular the coupling of N = 1 supergravity to grand unified theories like SU(5) and study the conditions which must be met in order to obtain a realistic model. Specific models are built in which local supersymmetry is broken at a scale √M_Wm_p ～ 10¹⁰ GeV. This breaking of supersymmetry is only detected at low energies through soft terms breaking explicitly the global supersymmetry. These soft terms (scalar masses, gaugino masses and trilinear scalar couplings) are renormalized at low energies according to the renormalization group. The (mass)² of the Higgs doublet evolve towards negative values at low energies giving rise to SU(2) × U(1) breaking as a radiative effect of local supersymmetry breaking. We finally point out the possible relevance of non-renormalizable superpotentials for the problem of fermion masses.     

Quasi goldstone fermions

We discuss a mechanism by which, in theories with an explicitly broken supersymmetry, we can obtain calculable fermion masses, provided certain softly broken R symmetries are incorporated. The corresponding fermion representations are determined by the pattern of internal symmetry breakdown. This mechanism is explicitly studied in a simple U(1) model. Prospects and limitations of this idea for constructing realistic fermion spectra are discussed.     

Vierbein singularities in CP2

The compact open four-dimensional manifold $\text{C}$P², with Euclidean metric, has recently attracted attention as an example of a spacetime in which fields of half-integral spin cannot be defined in the absence of additional structure (such as an electromagnetic background). In this note we identify the specific topological anomaly responsible for this phenomenon: $\text{C}$P² contains a class of two-dimensional spheres—“complex lines”— in small neighborhoods of each of which the two transverse degrees of freedom are forced to “twist” in a characteristic way. It is shown in detail how the twists force vierbeins—tetrads of orthonormal vector fields that play a central role in the theory of spinors—to have singularities on every complex line. As an aid to visualization we construct an example of a vierbein with, loosely speaking, the smallest possible set of singularities: It is ill-defined at every point of some one complex line and smooth everywhere else. The behavior of such a vierbein near any one of its singular points is characterized explicitly. The structure of the minimally singular vierbein is used to illuminate the observation of Hawking and Pope that in the presence of an appropriate electromagnetic background, fields of any spin can exist on $\text{C}$P² as long as their electric charges are correctly quantized, but that the charge values available to half-integral-spin fields differ from those available to integral-spin fields.     

IBFM form of SU(6/M) supergenerators for microscopic foundation

Canonical generators of the SU(6/M) supergroup are transformed to the IBFM form associated with the graded Schwinger realization which explicitly separates the SU(6)⊕SU(M) subalgebra. In the frame of this supersymmetry scheme we relate the IBFM hamiltonian to the microscopic quasiparticle-phonon hamiltonian.     

Explicit Construction of Supercharges of Supersymmetric Nonlinear Sigma Models in 1 + 1 Spacetime Dimensions

Considering the N = 1 supersymmetry transformations of supersymmetric nonlinear sigma models in 1 + 1 dimensions we construct explicitly conserved Noether currents associated with supersymmetry transformations and derive the associated conserved charges in terms of the basic fields. We compare this result with superspace calculations. Finally we review the connection between extended supersymmetry and the geometry of the target space and derive an explicit form of the supercharges for extended supersymmetry.     

N=2 boundary supersymmetry in integrable models and perturbed boundary conformal field theory

Boundary integrable models with N=2 supersymmetry are considered. For the simplest boundary N=2 superconformal minimal model with a Chebyshev bulk perturbation we show explicitly how fermionic boundary degrees of freedom arise naturally in the boundary perturbation in order to maintain integrability and N=2 supersymmetry. A new boundary reflection matrix is obtained for this model and N=2 boundary superalgebra is studied. A factorized scattering theory is proposed for a N=2 supersymmetric extension of the boundary sine-Gordon model with either (i) fermionic or (ii) bosonic and fermionic boundary degrees of freedom. Exact results are obtained for some quantum impurity problems: the boundary scaling Lee–Yang model, a massive deformation of the anisotropic Kondo model at the filling values g=2/(2n+3) and the boundary Ashkin–Teller model.     

Superprojectors

We present a simple algorithm for constructing the N-extended superfield projection operators for irreducible representations of supersymmetry, and explicitly perform all simplifications due to spinor derivative algebra. The method is based on covariant expansion of a general superfield in terms of chiral superfields, and requires no knowledge of Casimir operators. We list these superprojectors for various N = 1, 2, and 4 superfields, and apply our results to quantized the linearized N = 2 vector multiplet in a supersymmetric gauge.     

Heterotic p-branes from massive sigma models

We explicitly construct massive (0,4) supersymmetric ADHM sigma models which have heterotic p-brane solitons as their conformal fixed points. These yield the familiar gauge 5-brane and a new 1-brane solution which preserve half and a quarter of the space-time supersymmetry, respectively. We also discuss an analogous construction for the type 11 NS-NS p-branes using (4,4) supersymmetric models.     

Mixing-induced spontaneous supersymmetry breaking

It is conjectured that flavor mixing furnishes a universal mechanism for the spontaneous breaking of supersymmetry. The conjecture is proved explicitly for the mixing of two chiral N=1 supermultiplets and arguments for its general validity are given. That is an instance of the O?Raifeartaigh Lagrangian for which there is no tree-level nor perturbative breaking. Nonetheless, the dynamical breaking occurs due to the vacuum condensate, a mixing-induced nonperturbative effect that lifts the zero point energy.     

Another supersymmetric extension of local Lorentz symmetry in the vierbein formalism of Einstein gravity

A supersymmetric extension of the vierbein formalism of Einstein gravity is investigated by takingSL(N, 2;C) superalgebra, which is shown to be the sole possibility other than the previously investigatedOSp(N 2;C). After general discussion on the ξ-field realization, a non-linear realization of linear representation introduced in a previous paper, it is applied to the fundamental representation ofSL(N, 2;C) t0 which the vierbein supermultiplet belongs. The chiral symmetry derived in the theory is shown to beSO(N) in the same way as in theOSp(N,2;C)-symmetric extension.     

Four-dimensional supersymmetric black holes of type IIA superstring

We systematically construct a large class of four-dimensional supersymmetric black hole solutions of toroidally compactified type IIA superstring theory by explicitly solving the Killing spinor equations. They correspond to orthogonally intersecting configurations in ten dimensions. With the Kaluza-Klein monopole, they are parameterized by four charges and preserve of the N = 8 supersymmetry. We found a simple map to associate each charge with the corresponding Killing spinor constraints. The embedding of the N = 4 supersymmetry of a toroidally compactified heterotic string into the N = 8 supersymmetry of the IIA superstring was explicitly shown. We also found explicitly the configurations with only Ramond-Ramond charges, and those with both Neveu-Schwarz Neveu-Schwarz charges and Ramond-Ramond charges, including the dilaton and the internal metrics. The T-dual of these configurations were shown to satisfy the Killing spinor equations as well.     

Mass formula for pseudo-goldstone fermions in broken supersymmetry

The goldstino of spontaneously broken supersymmetry develops a mass in the presence of perturbations which violate supersymmetry explicitly. In analogy to the chiral dynamics of pions, the general current algebra formula for this mass is derived. It is verified and illustrated in simple models at the tree level or through loop expansions. Some subtleties of the renormalization and the vacuum stability of the relevant O'Raifeartaigh-type models are examined.     

N = 2 harmonic superspace with central charges and its application to self-interacting massive hypermultiplets

We investigate the structure of the harmonic superspace formalism with central charges for N = 2 supersymmetry, which is applicable to a wide class of N = 2 theories. As a simple application, the Lagrangian for self-interacting N = 2 massive scalar hypermultiplets is constructed in this formalism, and the interactions are explicitly obtained in terms of physical fields in the lowest order in the coupling constant. Although the theory looks highly unrenormalizable, remarkable cancellations take place so that all radiative corrections vanish in the lowest nontrivial order in the coupling constant.     

Covariant canonical formalism for gravity

We continue the previous discussion (A. D'Adda, J. E. Nelson, and T. Regge, Ann. Phys. (N.Y.)165) of the covariant canonical formalism for the group manifold and relate it to the standard canonical vierbein formalism as pioneered by Dirac. The form bracket is related to the Poisson bracket of classical mechanics. We utilise systematically the calculus of differential forms and a compound notation which labels Poincaré multiplets. In this way we obtain a particularly clear and compact expression for the Hamiltonian and the constraints algebra of the vierbein formalism.     

The supersymmetric Adler-Bardeen theorem and regularization by dimensional reduction

We examine the subtraction scheme dependence of the anomaly of the supersymmetric, gauge singlet axial current in pure and coupled supersymmetric Yang-Mills theories. Preserving supersymmetry and gauge invariance explicitly by using supersymmetric background field theory and dimensional reduction, we show that only the one-loop value of the axial anomaly is subtraction scheme independent, and that one can always define a subtraction scheme in which the Adler-Bardeen theorem is satisfied to all orders in perturbation theory. In general this subtraction scheme may be non-minimal, but in both the pure and the coupled theories, the Adler-Bardeen theorem is satisfied to two loops in minimal subtraction.