Related papers: Instanton Screening in the Nonperturbative Gluodyn…
Finite-size effects in the free energy density for Abelian (anti-)self-dual gluon field are investigated within $SU(3)$ gluodynamics. In particular, the role of gluon quasi-zero modes is studied. The effective potential is calculated within…
We calculate the lowest-dimensional nonlocal quark and gluon condensates within the single instanton approximation of the instanton liquid model. As a result, we determine the values of average virtualities of quarks $\lambda_q^2$ and…
We show how to do semiclassical nonperturbative computations within the worldline approach to quantum field theory using ``worldline instantons''. These worldline instantons are classical solutions to the Euclidean worldline loop equations…
We discuss non-perturbative effects in the ABJM model due to monopole instantons. We begin by constructing the instanton solutions in the $U(2)\times U(2)$ model, explicitly, and computing the Euclidean action. The Wick-rotated Lagrangian…
The contribution of instanton-induced effective inter-quark interactions to the baryon mass splittings was considered in the bag model. It is found that results are different from those obtained in the constituent quark model where the…
Instanton effects and three-loop perturbative contributions are incorporated into QCD sum-rule analyses of pseudoscalar ($J^{PC}=0^{-+}$) gluonium. Gaussian sum-rules are shown to be superior to Laplace sum-rules in optimized predictions…
In this talk, we compare two states: the stationary state in stochastic inflation and the ground state wave function of the universe. We already know that, for the potential with a static field, two pictures give the same probability…
The explicit multi-instanton solutions by 'tHooft and Jackiw, Nohl & Rebbi are generalized to curvilinear coordinates. The idea is that a gauge transformation can notably simplify the expressions obtained after the change of variables. The…
The contribution of the nonperturbative quark-gluon interaction induced by the instantons to $g_1^p(x,Q^2)$ and $F_2^p(x,Q^2)$ structure functions is estimated. It is shown that nontrivial $Q^2$ dependence of the instanton contribution to…
The concepts of an instanton vacuum and F-invariance are used to derive a complete effective theory of massless edge excitations in the quantum Hall effect. We establish, for the first time, the fundamental relation between the instanton…
A new process associated with the nonlinear optical properties of the electromagnetic vacuum, as predicted by quantum electrodynamics, is described. This can be called photon acceleration in vacuum, and corresponds to the frequency shift…
We compute instantonic effects in globally consistent T^6/Z2xZ2 orientifold models with discrete torsion and magnetised D-branes. We consider fractional branes and instantons wrapping the same rigid cycles. We clarify and analyse in detail…
Instanton-dyons, also known as instanton-monopoles or instanton-quarks, are topological constituents of the instantons at nonzero temperature and nonzero expectation value of $A_4$. While the interaction between instanton-dyons has been…
We discuss four-dimensional "spatially homogeneous" gravitational instantons. These are self-dual solutions of Euclidean vacuum Einstein's equations with potentially non-vanishing cosmological constant. They are endowed with a product…
We examine the role of instantons in the zero-temperature chiral phase transition in an SU(N) gauge theory. For a range of N_f (the number of fermion flavors) depending on N, the theory exhibits an infrared fixed point at coupling…
In recent years, significant progress was reached in understanding of vacuum and hadronic structure. We review recent works on the {\it point-to-point correlation functions}, comparing those obtained from phenomenology, ``instanton liquid"…
We investigate effects of field theory instantons by considering D-instantons in a suitable D3-brane background. In supersymmetric QCD with SU(N_c) gauge group with N_f=N_c flavors, the moduli space of vacua is deformed by instantons. This…
We investigate oscillating instanton solutions of a self-gravitating scalar field between degenerate vacua. We show that there exist O(4)-symmetric oscillating solutions in a de Sitter background. The geometry of this solution is finite and…
We remark that the weak coupling regime of the stochastic stabilization of 2D quantum gravity has a unique perturbative vacuum, which does not support instanton configurations. By means of Monte Carlo simulations we show that the…
Instanton contributions to the Laplace sum-rules for correlation functions of scalar gluonic currents are calculated. The role of the constant low-energy theorem term, whose substantial contribution is unique to the leading Laplace sum-rule…