相关论文: Edge Singularity in ``Induced QCD"
We study the behaviour of a universal combination of susceptibility and correlation length in the Ising model in two and three dimensions, in presence of both magnetic and thermal perturbations, in the neighbourhood of the critical point.…
Quantum polarization effects associated with the conformal anomaly in a static magnetic field background may generate a transverse electric current in the vacuum. The current may be produced either in an unbounded curved spacetime or in a…
Strassler's formulation of the string-derived Bern-Kosower formalism is extended to consider QED processes in homogeneous constant external field. A compact expression for the contribution of the one-loop with arbitrary number of external…
Recently, Kaplan proposed an interesting extension of QCD named Extended QCD or XQCD with bosonic auxiliary fields [1]. While its partition function is kept exactly the same as that of QCD, XQCD naturally contains properties of low-energy…
We construct composite operators in two-dimensional bosonized QCD, which obey a $W_\infty$ algebra, and discuss their relation to analogous objects recently obtained in the fermionic language. A complex algebraic structure is unravelled,…
QED_2 with mass and flavor has in common many features with QCD, and thus is an interesting toy model relevant for four dimensional physics. The model is constructed using Euclidean path integrals and mass perturbation series. The vacuum…
We study the spectrum of meson masses in large $N_c$ QCD$_2$ governed by celebrated 't Hooft's integral equation. We generalize analytical methods proposed by Fateev, Lukyanov and Zamolodchikov to the case of arbitrary, but equal quark…
Numerical results on the positronium spectrum in the front form of QED at large coupling constant are presented. Emphasis is put on the question whether one can derive an effective interaction at all, and whether this effective interaction…
We study a $\mathcal PT$-symmetric scalar Euclidean field theory with a complex action, using both theoretical analysis and lattice simulations. This model has a rich phase structure that exhibits pattern formation in the critical region.…
The limit of a large number of QCD colours gives a useful approximation scheme to the physical hadronic world. A brief overview of the mesonic sector is presented. The large-Nc constraints on the low-energy chiral couplings are summarized…
We analyse the meson spectrum in quenched QCD using lattice gauge theory. By studying hadron propagation with a variety of operators (both smeared and local), we are able to extract the ground state and first excited state masses with…
It is shown for a class of random, time-independent, square-integrable, three-dimensional magnetic fields that the one-loop effective fermion action of four-dimensional QED increases faster than a quadratic in B in the strong coupling…
Gauge theories induced by scalars in the fundamental representation of the $U(N_c)_{gauge}\times U(N_f)_{global}$ group are investigated in the large $N_c$ and $N_f$ limit. A master field is defined from bilinears of the scalar field…
A matrix model describing surfaces embedded in a Bethe lattice is considered. From the mean field point of view, it is equivalent to the Kazakov-Migdal induced gauge theory and therefore, at $N=\infty$ and $d>1$, the latter can be…
The inclusion of electromagnetic effects in unquenched QCD can be accomplished using ensembles generated in dynamical simulations with pure QCD provided the change in the quark determinant induced by a weak electromagnetic field can be…
A scalar field with an exponential potential has the particular property that it is attracted into a solution in which its energy scales as the dominant component (radiation or matter) of the Universe, contributing a fixed fraction of the…
Recent progress in quantum field theory and quantum gravity relies on mixed boundary conditions involving both normal and tangential derivatives of the quantized field. In particular, the occurrence of tangential derivatives in the boundary…
Effective field theory methods are used to study factorization of the deep inelastic scattering cross-section. The cross-section is shown to factor in QCD, even though it does not factor in perturbation theory for some choices of the…
We consider four scalar mesons scattering in large-Nc QCD. Using the worldline formalism we show that the scattering amplitude can be written as a formal sum over Wilson loops. The AdS/CFT correspondence maps this sum into a sum over string…
The meson spectrum of QCD is studied in the framework of nonperturbative QCD as a function of varying quark masses $m_q$. It is shown, that the total spectrum consists of two branches: 1) the standard one, which may be called the flux-tube…