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New Chern-Simons densities in both odd and even dimensions
Get PDFAfter reviewing briefly the dimensional reduction of Chern–Pontryagin densitie, we define new Chern–Simons densities expressed in terms of Yang-Mills and Higgs fields. These are defined in all dimensions, including in even dimensional spacetimes. They are constructed by subjecting the dimensionally reduced Chern–Pontryagin densites to further descent by two steps
On free quotients of complete intersection Calabi-Yau manifolds
Get PDFIn order to find novel examples of non-simply connected Calabi-Yau three-folds, free quotients of complete intersections in products of projective spaces are classified by means of a computer search. More precisely, all automorphisms of the product of projective spaces that descend to a free action on the Calabi-Yau manifold are identified
Numerical Hermitian Yang-Mills connections and vector bundle stability in heterotic theories
Get PDFA numerical algorithm is presented for explicitly computing the gauge connection on slope-stable holomorphic vector bundles on Calabi-Yau manifolds. To illustrate this algorithm, we calculate the connections on stable monad bundles defined on the K3 twofold and Quintic threefold. An error measure is introduced to determine how closely our algorithmic connection approximates a solution to the Hermitian Yang-Mills equations. We then extend our results by investigating the behavior of non slope-stable bundles. In a variety of examples, it is shown that the failure of these bundles to satisfy the Hermitian Yang-Mills equations, including field-strength singularities, can be accurately reproduced numerically. These results make it possible to numerically determine whether or not a vector bundle is slope-stable, thus providing an important new tool in the exploration of heterotic vacua
Entanglement of a two-particle Gaussian state interacting with a heat bath
Get PDFThe effect of a thermal reservoir is investigated on a bipartite Gaussian state. We derive a pre-Lindblad master equation in the non-rotating wave approximation for the system. We then solve the master equation for a bipartite harmonic oscillator Hamiltonian with entangled initial state. We show that for strong damping the loss of entanglement is the same as for freely evolving particles. However, if the damping is small, the entanglement is shown to oscillate and eventually tend to a constant nonzero value
Modular symmetry and temperature flow of conductivities in quantum Hall systems with varying Zeeman energy
Get PDFThe behaviour of the critical point between quantum Hall plateaux, as the Zeeman energy is varied, is analysed using modular symmetry of the Hall conductivities following from the law of corresponding states. Flow diagrams for the conductivities as a function of temperature, with the magnetic field fixed, are constructed for different Zeeman energies, for samples with particle-hole symmetry
Mionteangú na Gaeilge
Get PDFTá cur síos san alt seo ar chur chuige Fishmanach maidir le mionteangú na Gaeilge. Tráchtaim ar an nua-aoiseachas agus a chuid impleachtaí le haghaidh mhionteangacha an domhain. Tá cur síos ann ar imeallú na Gaeilge agus mionteangacha go ginearálta i gcomhthéacs sochshíceolaíochta mórtheanga fearacht an Bhéarla. Spíonaim castachtaí i leith an dátheangachais fhadsaolaigh i bhfianaise an bhaile ilteangaigh Cupvar san India; agus an fabht don mhionteanga atá sa ngaol dátheangach le mórtheanga. Tráchtaim ar shealbhú laghdaithe agus neamhthraidisiúnta na Gaeilge; agus ar anáil il-láithreacht na meán cumarsáide. Ar deireadh, tugaim moltaí maidir le tacú le sealbhú optamach na Gaeilge agus maidir le Tearmann Gaeilge le pobal Gael a tharrtháil
Hot defect superconformal field theory in an external magnetic field
Get PDFIn this paper we investigate the influence of an external magnetic field on a flavored holographic gauge theory dual to the D3/D5–brane intersection at finite temperature. Our study shows that the external magnetic field has a freezing effect on the meson melting phase transition. We construct the corresponding phase diagram. We investigate some thermodynamic quantities of the theory. A study of the entropy density reveals enhanced relative jump of the entropy density at the “chiral” phase transition. A study of the magnetization shows that both the confined and deconfined phases exhibit diamagnetic response. The diamagnetic response in the deconfined phase has a stronger temperature dependence reflecting the temperature dependence of the conductivity. We study the meson spectrum of the theory and analyze the stability of the different phases by looking at both normal and quasinormal semi-classical excitations. For the symmetry breaking phase we analyze the corresponding pseudo–Goldstone modes and prove that they satisfy non-relativistic dispersion relation
The Zero Temperature Phase Diagram of the Kitaev Model
Get PDFWe show that the zero temperature phase diagram of the vortex free sector of the Kitaev model is in one to one correspondence with that of the classical dimer model on the same lattice. We find that the model generically has three distinct phases. On a honeycomb lattice with a 3 × 3 fundamental domain all three phases are accessible. As the couplings are varied there are two distinct transitions. The new transition is one to a gapped phase that opens up in the interior of the B phase