1207 research outputs found
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Backreacted flavor in non-commutative gauge theories
Get PDFWe construct the gravity dual of N = 1 Non-Commutative SYM theory coupled to N_f smeared massless fundamental flavors. Our solution is analytic and non-perturbative. Near the origin the background reduces to the one corresponding to an ordinary SYM theory. At large radial distances, the dilaton diverges signaling the presence of a UV Landau pole. Considering a probe D3–brane we calculate the effective YM coupling and show that it is independent on the parameter of non-commutativity. We calculate the corresponding beta function and show that it remains positive at all energy scales
Characterization of a Crustal Transition Zone in Northern Tibet using Magnetotelluric Modelling
Get PDFThe overall objective of the final phase of the INDEPTH (International Deep Profiling of Tibet and Himalaya) project has been to develop a better understanding of the structure and evolution of the northern margins of the Tibetan plateau, namely the Kunlun and Altyn Tagh faults. For the Kunlun Fault, both INDEPTH Phase III and new Phase IV magnetotelluric (MT) data were investigated using 2D isotropic and anisotropic modelling, as well as 3D modelling. The resulting resistivity models characterize a northwards penetrative extension of the partially molten Tibetan middle crust, crossing the subvertical Kunlun Fault. Furthermore, the anisotropic observations highlighted by the INDEPTH MT modelling define progressive finger-like melt intrusion beneath the Kunlun Shan. However, this intrusion may not be homogeneous along the whole of the northern Tibetan border along the Kunlun Fault, as its depth and horizontal extension are likely to vary. The partial melt associated with the anisotropic anomaly observed on the INDEPTH resistivity models may have been triggered by strain heating associated with heat production during ductile deformation in a mid-crustal shear zone located beneath the Kunlun fault in the southern Kunlun ranges. This shear zone might be characterized by different levels of strain along the whole of the northern Tibetan border and may have developed into separated channels where the Songpan-Ganzi partially molten crust flows to the north, mechanically weakening the Kunlun crust. Melt penetration across the Kunlun Fault through intrusive channels likely accommodates crustal shortening in northern Tibet, but may also characterize a transition zone between the weak partially molten crust of the plateau and the more rigid Qaidam lithosphere, associated with the growth of the plateau to the north
Electrically charged black branes in N=4^+, D=5 gauged supergravity
Get PDFWe analyze the properties of asymptotically AdS electrically charged black brane solutions in a consistent truncation of the N = 4^+ , D = 5 Romans’ gauged supergravity which contains gravity, SU(2) and U(1) gauge fields, and a dilaton possessing a nontrivial potential approaching a constant negative value at infinity. We find that the U(1) × U(1) solutions become unstable to forming non-Abelian hair. These configurations emerge as zero modes of the Abelian solutions at critical temperature and a critical (nonvanishing) ratio of the electric charges and can be viewed as holographic p−wave superfluids
New global F-theory GUTs with U(1) symmetries
Get PDFWe construct global F-theory GUTs with SU(5)×U(1) gauge group defined by specifying a fully resolved Calabi-Yau fourfold and consistent four-form G-flux. Its specific U(1) charged matter spectrum allows the desired Yukawa couplings, but forbids dangerous proton decay operators. The model we find: (1) does not follow from an underlying higgsed E_8 gauge group (2) leaves the class of theories that can be analyzed with current split-spectral cover techniques. This avoids recently proposed no-go theorems for models with hypercharge flux, as required to break the GUT group. The appearance of additional fields is related geometrically to considering a more general class of sections and 4–1 splits. We show explicitly that the four-dimensional chiral matter index can still be computed using three-dimensional one-loop Chern-Simons terms
Quantum slit diffraction in space and in time of a Gaussian wave packet and semi-classical approximation
Get PDFWe revisit the famous problem of quantum slit diffraction of a three-dimensional Gaussian wave packet, taking into account the diffraction in time phenomenon for a reflective or absorbing slit. We first recall the theory of diffraction in space and in time to give an explicit integral formula for the single-slit propagator (for a two-dimensional aperture) assuming that the time of opening the aperture coincides with the time of emission of the particle. Then we derive a semiclassical expression for the amplitude when the parameter μ = m(|r|^2)/(ħt) is large, where r is the position of the particle with mass m detected on the screen at the time t. We also give corrections to the law giving the distance between two fringes in the Fraunhofer regime when the distances of the apparatus in the propagation direction are large compared to the size of the aperture of the slit. To conclude, we discuss the phenomenological consequences and we give a new perspective to investigate the quantum diffraction phenomenon particulary for the cold atom slit experiment
A non-Abelian Chern-Simons-Yang-Mills-Higgs system in 3+1 dimensions
Get PDFWe study spherically symmetric solutions of an SO(5) Chern-Simons–Yang-Mills-Higgs system in 3 + 1 dimensions. The Chern-Simons densities are defined in terms of both Yang-Mills fields and a 5-component isomultiplet Higgs. The SO(3) × SO(2) solutions are analysed in a systematic way, by employing numerical methods. These finite energy configurations possess both electric and magnetic global charges, differing radically, however, from Julia-Zee dyons. When two or more of these Chern-Simons densities are present in the Lagrangian, solutions with vanishing electric charge but nonvanishing electrostatic potential may exist
CFTs on Riemann surfaces of genus g ≥ 1: dependence on moduli
Get PDFThe dependence of the Virasoro-N-point function on the moduli of the Riemann surface is investigated. We propose an algebraic geometric approach that applies to any hyperelliptic Riemann surface. Our discussion includes a demonstration of our methods with the case g = 1
A Tipperary emigrant's manuscript
Get PDFA description, with historical background, of an Irish manuscript discovered in Quebec City and now deposited in the National Library of Ireland. The manuscript was brought to Quebec in the 1820s by an emigrant from Co. Tipperary