We discuss the analytic presentations of the high-order correlation functions in the N-slit diffraction with thermal light in a recent paper [Phys. Rev. Lett. 109, 233603 (2012)]. Our analysis shows that the superresolving fringes in the high-order correlation measurement have two classical counterparts.
Using supersymmetric localization, we consider four-dimensional $mathcal{N}=2$ superconformal quiver gauge theories obtained from $mathbb{Z}_n$ orbifolds of $mathcal{N}=4$ Super Yang-Mills theory in the large $N$ limit at weak coupling. In particular, we show that: 1) The partition function for arbitrary couplings can be constructed in terms of universal building blocks. 2) It can be computed in perturbation series, which converges uniformly for $|lambda_I|<pi^2$, where $lambda_I$ are the t Hooft coupling of the gauge groups. 3) The perturbation series for two-point functions can be explicitly computed to arbitrary orders. There is no universal effective coupling by which one can express them in terms of correlators of the $mathcal{N}=4$ theory. 4) One can define twisted and untwisted sector operators. At the perturbative orbifold point, when all the couplings are the same, the correlators of untwisted sector operators coincide with those of $mathcal{N}=4$ Super Yang-Mills theory. In the twisted sector, we find remarkable cancellations of a certain number of planar loops, determined by the conformal dimension of the operator.
We describe a new approach to computing the chiral part of correlation functions of stress-tensor supermultiplets in N=4 SYM that relies on symmetries, analytic properties and the structure of the OPE only. We demonstrate that the correlation functions are given by a linear combination of chiral N=4 superconformal invariants accompanied by coefficient functions depending on the space-time coordinates only. We present the explicit construction of these invariants and show that the six-point correlation function is fixed in the Born approximation up to four constant coefficients by its symmetries. In addition, the known asymptotic structure of the correlation function in the light-like limit fixes unambiguously these coefficients up to an overall normalization. We demonstrate that the same approach can be applied to obtain a representation for the six-point NMHV amplitude that is free from any auxiliary gauge fixing parameters, does not involve spurious poles and manifests half of the dual superconformal symmetry.
We compute correlation functions of chiral primary operators in N=2 superconformal theories at large N using a construction based on supersymmetric localization recently developed by Gerchkovitz et al. We focus on N=4 SYM as well as on superconformal QCD. In the case of N=4 we recover the free field theory results as expected due to non-renormalization theorems. In the case of superconformal QCD we study the planar expansion in the large N limit. The final correlators admit a simple generalization to a finite N formula which exactly matches the various small $N$ results in the literature.
Gauged N=8 supergravity in four dimensions is now known to admit a deformation characterized by a real parameter $omega$ lying in the interval $0leomegale pi/8$. We analyse the fluctuations about its anti-de Sitter vacuum, and show that the full N=8 supersymmetry can be maintained by the boundary conditions only for $omega=0$. For non-vanishing $omega$, and requiring that there be no propagating spin s>1 fields on the boundary, we show that N=3 is the maximum degree of supersymmetry that can be preserved by the boundary conditions. We then construct in detail the consistent truncation of the N=8 theory to give $omega$-deformed SO(6) gauged N=6 supergravity, again with $omega$ in the range $0leomegale pi/8$. We show that this theory admits fully N=6 supersymmetry-preserving boundary conditions not only for $omega=0$, but also for $omega=pi/8$. These two theories are related by a U(1) electric-magnetic duality. We observe that the only three-point functions that depend on $omega$ involve the coupling of an SO(6) gauge field with the U(1) gauge field and a scalar or pseudo-scalar field. We compute these correlation functions and compare them with those of the undeformed N=6 theory. We find that the correlation functions in the $omega=pi/8$ theory holographically correspond to amplitudes in the U(N)_k x U(N)_{-k} ABJM model in which the U(1) Noether current is replaced by a dynamical U(1) gauge field. We also show that the $omega$-deformed N=6 gauged supergravities can be obtained via consistent reductions from the eleven-dimensional or ten-dimensional type IIA supergravities.
In traditional Hanbury Brown and Twiss (HBT) schemes, the thermal intensity-intensity correlations are phase insensitive. Here we propose a modified HBT scheme with phase conjugation to demonstrate the phase-sensitive and nonfactorizable features for thermal intensity-intensity correlation speckle. Our scheme leads to results that are similar to those of the two-photon speckle. We discuss the possibility of the experimental realization. The results provide us a deeper insight of the thermal correlations and may lead to more significant applications in imaging and speckle technologies.