General N=1 supersymmetric flux vacua of massive type IIA string theory

We derive conditions for the existence of four-dimensional N=1 supersymmetric flux vacua of massive type IIA string theory with general supergravity fluxes turned on. For an SU(3) singlet Killing spinor, we show that such flux vacua exist when the internal geometry is nearly K?hler. The geometry is not warped, all the allowed fluxes are proportional to the mass parameter, and the dilaton is fixed by a ratio of (quantized) fluxes. The four-dimensional cosmological constant, while negative, becomes small in the vacuum with the weak string coupling.     

On quasi-self-dual fields in N=4 supersymmetric Yang-Mills theory

A general representation for a quasi-self-dual gauge field which is a generalization of the 't Hooft ansatz is obtained in the Euclidean conformally invariant Yang-Mills theory with a sextuplet of real scalar fields-the boson sector of N=4 supersymmetric Yang-Mills theory. The existence of an O(4)-symmetric quasi-self-dual solution in the region g ²>0 is proved. An explicit example of the quasi-self-dual instanton in the region g ²<0 is constructed.     

N = 1 complex supersymmetric theory in the harmonic superspace

The N = 1 complex supersymmetric algebra is studied using the harmonic techniques. The massless representations and the classification of their field content in terms of SU(2) n-uplets is obtained. The superspace formulation is developed and the U(1) × U(1) gauge supermultiplet is examined. Other features are discussed.     

Metamaterials mimicking dynamic spacetime,D-brane and noncommutativity in string theory

We propose a scheme to mimic the expanding cosmos in 1+2$1+2$ dimensions in laboratory. Furthermore, we develop a general procedure to use nonlinear metamaterials to mimic D-brane and noncommutativity in string theory.     

Vanishing three-loop beta function in N = 4 supersymmetric Yang-Mills theory

We have calculated the beta function of the N = 4 supersymmetric Yang-Mills theory through three-loop order and find that it is zero. The calculation was performed using superspace techniques that also allowed the calculation of the complete three-loop chiral-multiplet propagator, which turned out to be quite simple. These results strongly support the speculations that the theory is finite order-by-order in perturbation theory.     

N=1 supersymmetric truncations and the superstring low-energy effective theory

The question of discarding heavy fields in N=1 supersymmetric theories is analyzed. The analysis is applied to the compactification of the E₈ × E₈ superstring.     

Dijet production at large rapidity separation in N = 4 supersymmetric Yang-Mills theory

Ratios of azimuthal angle correlations between two jets produced at large rapidity separation are studied in the N = 4 maximally supersymmetric Yang-Mills (MSYM) theory. It is shown that these observables, which directly prove the SL(2,C) symmetry present in gauge theories in the Regge limit, exhibit an excellent perturbative convergence. They are compared to those calculated in QCD for different renormalization schemes concluding that the momentum-substraction scheme with the Brodsky-Lepage-Mackenzie scale-fixing procedure captures the bulk of the MSYM results.     

Thermal spectral functions of strongly coupled N = 4 supersymmetric Yang-Mills theory

We use the gauge-gravity duality conjecture to compute spectral functions of the stress-energy tensor in finite-temperature N = 4 supersymmetric Yang-Mills theory in the limit of large N(c) and large 't Hooft coupling. The spectral functions exhibit peaks characteristic of hydrodynamic modes at small frequency, and oscillations at intermediate frequency. The nonperturbative spectral functions differ qualitatively from those obtained in perturbation theory. The results may prove useful for lattice studies of transport processes in thermal gauge theories.     

Lagrangian of the N = 1 supersymmetric Yang-Mills theory in the formalism of unified field

A method is proposed to use matrix nonlinear equations in order to construct the Lagrangian of the N = 1 supersymmetric Yang-Mills theory and the algebra of generators of transformations, closed off-shell in the 1.5-order formalism. Contrary to the superfield approach, there is no need to impose a Wess—Zumino type gauge fixing.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 16–21, September 1989.     

Restoring reality for the self-dual N = 2 string

It is known that the critical N = (2,2) string describes 2 + 2 dimensional self-dual gravity in a non-covariant form, since it requires the choice of a complex structure in the target, which leaves only U(1,1) Lorentz symmetry. We briefly review picture-changing and spectral flow and show that the world-sheet Maxwell instantons individually break the Lorentz group further to SU(1,1). However, their contributions conspire to restore full SO(2,2) global symmetry if dilaton and axion fields are assembled in a null anti-self-dual two-form, denying them the status of Lorentz scalars. We present the fullySO (2,2) invariant tree-level three-point amplitude and the corresponding extension of the Plebanski action for self-dual gravity.     

Renormalization of N = 1 supersymmetric Yang-Mills theories: (I). The classical theory

We investigate the classical N = 1 supersymmetric Yang-Mills theories and pay special attention to the search for the most general action fulfilling the Slavnov identity used to define the theory. It turns out that the well-known action of Ferrara, Zumino and Salam, Strathdee represents a special case, our general solution being equivalent to it through a redefinition of the gauge-fixing condition.