Diana Vaman

Holographic duals of flavored N = 1 super Yang-Mills: beyond the probe approximation

We construct backreacted D3/D7 supergravity backgrounds which are dual to four-dimensional N = 1 and N = 2 supersymmetric Yang-Mills at large Nc with ∞avor quarks in the fundamental representation of SU(Nc). We take into account the backreaction of D7-branes on either AdS5£S 5 or AdS5£T 1;1 , or more generically on backgrounds where the space transverse to the D3-branes is Kahler. The construction of the backreacted geometry splits into two stages. First we determine the modiflcation of the six-dimensional space transverse to the D3 due to the D7, and then we compute the warp factor due to the D3. TheN = 2 background corresponds to placing a single stack of Nf D7-branes in AdS5£S 5 . Here the Kahler potential is known exactly, while the warp factor is obtained in certain limits as a perturbative expansion. By placing another D7 0 probe in the backreacted D3/D7 background, we derive the efiect of the D7-branes on the spectrum of the scalar ∞uctuations to flrst order in Nf. The two systems with N = 1 supersymmetry that we discuss are D3/D7/D7 0 and D3/D7 on the conifold. In both cases, the Kahler potential is obtained perturbatively in the number of D7-branes. We provide all the ingredients necessary for the computation of each term in the expansion, and in each case give the flrst few terms explicitly. Finally, we comment on some aspects of the dual gauge theories.

Regge trajectories for mesons in the holographic dual of large-N(c) QCD

We discuss Regge trajectories of dynamical mesons in large-Nc QCD, using the supergravity background describing Nc D4-branes compactified on a thermal circle. The flavor degrees of freedom arise from the addition of Nf << Nc D6 probe branes. Our work provides a string theoretical derivation, via the gauge/string correspondence, of a phenomenological model describing the meson as rotating point-like massive particles connected by a flux string. The massive endpoints induce nonlinearities for the Regge trajectory. For light quarks the Regge trajectories of mesons are essentially linear. For massive quarks our trajectories qualitatively capture the nonlinearity detected in lattice calculations.

Bit strings from Script N = 4 gauge theory

We present an improvement of the interacting string bit theory proposed in [1], designed to reproduce the non-planar perturbative amplitudes between BMN operators in = 4 gauge theory. Our formalism incorporates the effect of operator mixing and all non-planar corrections to the inner product. We use supersymmetry to construct the bosonic matrix elements of the light-cone hamiltonian to all orders in g2, and make a detailed comparison with the non-planar amplitudes obtained from gauge theory to order g22. We find a precise match.

Tracing the string: BMN correspondence at finite J2/N

Employing the string bit formalism of [18], we identify the basis transformation that relates BMN operators in = 4 gauge theory to string states in the dual string field theory at finite g2 = J2/N. In this basis, the supercharge truncates at linear order in g2, and the mixing amplitude between 1 and 2-string states precisely matches with the (corrected) answer of [5] for the 3-string amplitude in light-cone string field theory. Supersymmetry then predicts the order g22 contact term in the string bit hamiltonian. The resulting leading order mass renormalization of string states agrees with the recently computed shift in conformal dimension of BMN operators in the gauge theory.

Regge trajectories revisited in the gauge / string correspondence

Abstract We attempt to obtain realistic glueball Regge trajectories from the gauge/string correspondence. To this end we study closed spinning string configurations in two supergravity backgrounds: Klebanov–Strassler (KS) and Maldacena–Nunez (MN) which are dual to confining gauge theories. These backgrounds represent two embeddings of N =1 SYM, in the large rank N limit, in string theory. The classical configuration that we consider is that of a folded closed string spinning in a supergravity region with vanishing transverse radius (τ=0) which is dual to the IR of the gauge theory. Classically, a spinning string yields a linear Regge trajectory with zero intercept. By performing a semi-classical analysis we find that quantum effects alter both the linearity of the trajectory and the vanishing classical intercept: J≡α(t)=α 0 +α′t+β t . Two features of our Regge trajectories are compatible with the experimental pomeron trajectory: positive intercept and positive curvature. The fact that both KS and MN string backgrounds give the same functional expression of the Regge trajectories suggests that in fact we are observing string states dual to N =1 SYM.

Strings in the Ramond-Ramond plane wave background at finite temperature

We calculate the thermal partition function in the canonical ensemble for type IIB superstrings in the plane wave background with a constant null RR five-form. The Hagedorn temperature is found to be higher than the corresponding value for strings in flat space. In the limit corresponding to the weakly coupled field theory we find that the Hagedorn temperature is pushed to infinity. The key property of strings in the plane wave background under investigation on which our result relies is that the effective mass of the bosonic and fermionic coordinates in the light-cone gauge is proportional to the momentum

On black hole thermodynamics of 2-D type 0A

{p}^{+}.

Spinning particles in Taub-NUT space

The free energy is finite as the Hagedorn temperature is approached from below, suggesting a possible phase transition.

Supersymmetries and constants of motion in Taub - NUT spinning space

Wepresentadetailedanalysisofthethermodynamicsoftwodimensionalblack hole solutions to type 0A with q unitsof electric andmagnetic ∞ux. We compute the free energyandderivedquantitiessuchasentropyandmassforanarbitrarynon-extremalblack hole. Thefree energy is non-vanishing, in contrast to the case of dilatonic 2-d black holes withoutelectric andmagnetic ∞uxes. Theentropyoftheextremalblackholesisobtained, and we flnd it to be proportional to q 2 , the square of the RR ∞ux. We compare these thermodynamicsquantities withthose fromcandidate matrix modelduals.

On horizons and plane waves

The geodesic motion of pseudoclassical spinning particles in Euclidean Taub-NUT space is analyzed. The constants of motion are expressed in terms of Killing-Yano tensors. Some previous results from the literature are corrected.