Non-Equilibrium Production of Photons via \pi^0\to 2\gamma in DCC's

We study production of photons via the non-equilibrium relaxation of a Disoriented Chiral Condensate with the chiral order parameter having a large initial amplitude along the \pi^0 direction. Assuming the validity of the low energy coupling of the neutral pion to photons via the U_A(1) anomalous vertex, we find that for large initial amplitudes along the \pi^0 direction, photon production is enhanced by parametric amplification. These processes are non-perturbative with a large contribution during the non-equilibrium stages of the evolution and result in a distinct distribution of the produced photons and a polarization asymmetry. For initial amplitudes of the \pi^0 component of the order parameter between 200-400 MeV, corresponding to energy densities between 1-12 GeV/fm^3 we find a peak in the photon distribution at energies between \approx 300 -600 MeV. We also find polarization asymmetries typically between 5-10%. We discuss the potential experimental impact of these results as well as the problems associated with its detection.Comment: 36 pages, 14 figures, uses revte

Women\u27s Schooling, Home Teaching, and Economic Growth

The hypothesis that increases in the schooling of women enhance the human capital of the next generation and thus make a unique contribution to economic growth is assessed on the basis of data describing green revolution India. Estimates are obtained that indicate that a component of the significant and positive relationship between maternal literacy and child schooling in the Indian setting reflects the productivity effect of home teaching and that the existence of this effect, combined with the increase in returns to schooling for men, importantly underlies the expansion of female literacy following the onset of the green revolution

Women\u27s Schooling, Home Teaching, and Economic Growth

The hypothesis that increases in the schooling of women enhance the human capital of the next generation and thus make a unique contribution to economic growth is assessed on the basis of data describing green revolution India. Estimates are obtained that indicate that a component of the significant and positive relationship between maternal literacy and child schooling in the Indian setting reflects the productivity effect of home teaching and that the existence of this effect, combined with the increase in returns to schooling for men, importantly underlies the expansion of female literacy following the onset of the green revolution

Intermediate progenitors support migration of neural stem cells into dentate gyrus outer neurogenic niches.

The hippocampal dentate gyrus (DG) is a unique brain region maintaining neural stem cells (NCSs) and neurogenesis into adulthood. We used multiphoton imaging to visualize genetically defined progenitor subpopulations in live slices across key stages of mouse DG development, testing decades old static models of DG formation with molecular identification, genetic-lineage tracing, and mutant analyses. We found novel progenitor migrations, timings, dynamic cell-cell interactions, signaling activities, and routes underlie mosaic DG formation. Intermediate progenitors (IPs, Tbr2+) pioneered migrations, supporting and guiding later emigrating NSCs (Sox9+) through multiple transient zones prior to converging at the nascent outer adult niche in a dynamic settling process, generating all prenatal and postnatal granule neurons in defined spatiotemporal order. IPs (Dll1+) extensively targeted contacts to mitotic NSCs (Notch active), revealing a substrate for cell-cell contact support during migrations, a developmental feature maintained in adults. Mouse DG formation shares conserved features of human neocortical expansion

Photoproduction Enhancement from Non Equilibrium Disoriented Chiral Condensates

We study photoproduction during the non-equilibrium stages of the formation of chiral condensates within the ``quench'' scenario of the chiral phase transition. The dynamics is modeled with a gauged linear sigma model. A novel quantum kinetic approach to the description of photoproduction far off equilibrium is developed. We find that non-equilibrium spinodal instabilities of long wavelength pion fluctuations are responsible for an enhanced photoproduction rate for energies $\leq 80$ MeV at order $\alpha$. These non-equilibrium effects lead to a larger contribution than the typical processes in the medium, including that of the anomalous neutral pion decay $\pi^0 \rightarrow 2 \gamma$ (which is of order $\alpha^2$). We follow the evolution of the dynamics throughout the phase transition, which in this scenario occurs on a time scale of about $2.5-3$ fm/c and integrate the photon yield through its evolution. The spectrum of photons produced throughout the phase transition is a non- equilibrium one. For thermal initial conditions at the time of the quench it interpolates between a thermal distribution about 6% above the initial temperature (at the time of the quench) for low energy $\leq 80$ MeV photons, and a high energy tail in thermal equilibrium at the initial temperature, with a smooth crossover at 100 MeV. The rate displays a peak at $\sim 35$ MeV which receives a larger enhancement the closer the initial temperature at the time of the quench is to the critical temperature. It is found that the enhancement of photoproduction at low energies is not an artifact caused by the initial distribution of the photons, but is due to the pionic instabilities. We suggest that these strong out of equilibrium effects may provide experimental signatures for the formation and relaxation of DCC's in heavy ion collisions.Comment: 33 pages, 11 figures, uses revtex and epsfi

The O(N) model on a squashed S^3 and the Klebanov-Polyakov correspondence

We solve the O(N) vector model at large N on a squashed three-sphere with a conformal mass term. Using the Klebanov-Polyakov version of the AdS_4/CFT_3 correspondence we match various aspects of the strongly coupled theory with the physics of the bulk AdS Taub-NUT and AdS Taub-Bolt geometries. Remarkably, we find that the field theory reproduces the behaviour of the bulk free energy as a function of the squashing parameter. The O(N) model is realised in a symmetric phase for all finite values of the coupling and squashing parameter, including when the boundary scalar curvature is negative.Comment: 1+27 pages. 6 figures. LaTeX. References adde

Soliton Squeezing in a Mach-Zehnder Fiber Interferometer

A new scheme for generating amplitude squeezed light by means of soliton self-phase modulation is experimentally demonstrated. By injecting 180-fs pulses into an equivalent Mach-Zehnder fiber interferometer, a maximum noise reduction of $4.4 \pm 0.3$ dB is obtained ($6.3 \pm 0.6$ dB when corrected for losses). The dependence of noise reduction on the interferometer splitting ratio and fiber length is studied in detail.Comment: 5 pages, 4 figure

Quantum Noise Randomized Ciphers

We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by the salient feature responsible for their increased security. We describe a concrete system known as AlphaEta and show that it is equivalent to a random cipher in which the required randomization is effected by coherent-state quantum noise. We describe the currently known security features of AlphaEta and similar systems, including lower bounds on the unicity distances against ciphertext-only and known-plaintext attacks. We show how AlphaEta used in conjunction with any standard stream cipher such as AES (Advanced Encryption Standard) provides an additional, qualitatively different layer of security from physical encryption against known-plaintext attacks on the key. We refute some claims in the literature that AlphaEta is equivalent to a non-random stream cipher.Comment: Accepted for publication in Phys. Rev. A; Discussion augmented and re-organized; Section 5 contains a detailed response to 'T. Nishioka, T. Hasegawa, H. Ishizuka, K. Imafuku, H. Imai: Phys. Lett. A 327 (2004) 28-32 /quant-ph/0310168' & 'T. Nishioka, T. Hasegawa, H. Ishizuka, K. Imafuku, H. Imai: Phys. Lett. A 346 (2005) 7

An N=1 duality cascade from a deformation of N=4 SUSY Yang-Mills

We study relevant deformations of an N=1 superconformal theory which is an exactly marginal deformation of U(N) N=4 SUSY Yang-Mills. The resulting theory has a classical Higgs branch that is a complex deformation of the orbifold C^3/Z_n x Z_n that is a non-compact Calabi-Yau space with isolated conifold singularities. At these singular points in moduli space the theory exhibits a duality cascade and flows to a confining theory with a mass gap. By exactly solving the corresponding holomorphic matrix model we compute the exact quantum superpotential generated at the end of the duality cascade and calculate precisely how quantum effects deform the classical moduli space by replacing the conifold singularities with three-cycles of finite size. Locally the structure is that of the deformed conifold, but the global geometry is different. This desingularized quantum deformed geometry is the moduli space of probe D3-branes at the end of a duality cascade realized on the worldvolume of (fractional) D3-branes placed at the isolated conifold singularities in the deformation of the orbifold C^3/Z_n x Z_n with discrete torsion.Comment: Uses Latex, JHEP.cls, 43 pages, 3 figure