相关论文: Relativistic, model-independent determination of e…
We present a model-independent and relativistic approach to analytically derive electromagnetic finite-size effects beyond the point-like approximation. The key element is the use of electromagnetic Ward identities to constrain vertex…
We consider electromagnetic finite-volume effects through order $1/L^3$ in different formulations of QED, where $L$ is the periodicity of the spatial volume. An inherent problem at this order is the appearance of structure-dependent…
In Carrasco et al. we have recently proposed a method to calculate $O(e^2)$ electromagnetic corrections to leptonic decay widths of pseudoscalar mesons. The method is based on the observation that the infrared divergent contributions (that…
The relativistic calculations of the electromagnetic form factors and static moments of $\rho$-meson are given in the framework of the relativistic Hamiltonian dynamics with different model wave functions. The impulse approximation is used.…
We demonstrate that the leading and next-to-leading finite-volume effects in the evaluation of leptonic decay widths of pseudoscalar mesons at $O(\alpha)$ are universal, i.e. they are independent of the structure of the meson. This is…
We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the…
The electromagnetic form factors of $\pi$ and $K$ mesons and deuteron are calculated in modified impulse approximation using instant form of relativistic Hamiltonian dynamics. The different model wave functions are used. Meson wave function…
We present a non-perturbative lattice calculation of the form factors which contribute to the amplitudes for the radiative decays $P\to \ell \bar \nu_\ell \gamma$, where $P$ is a pseudoscalar meson and $\ell$ is a charged lepton. Together…
In this talk we present some preliminary results and discuss the prospects of determining the leading structure-dependent finite-volume effects in the hadronic vacuum polarisation associated to order $e^2$ electromagnetic corrections. In…
We study the Effective Field Theory of Large Scale Structure for cosmic density and momentum fields. We show that the finite part of the two-loop calculation and its counterterms introduce an apparent scale dependence for the leading order…
A study of electromagnetic structure of the deuteron in the framework of relativistic quantum mechanics is presented. The deuteron form factors dependencies on the transferred 4-momentum Q are calculated. We compare results obtained with…
The formation of local magnetic moments and its size effect in one- and three-dimension finite systems with magnetic impurity are investigated based on the Anderson hybridizing model in real space. By the exact diagonalization within the…
The electromagnetic form factors of light and heavy pseudoscalar mesons are calculated within two covariant constituent-quark models, a light-front and a dispersion relation approach. We investigate the details and physical origins of the…
We present a non-perturbative calculation of the form factors which contribute to the amplitudes for the radiative decays $P\to \ell \bar \nu_\ell \gamma$, where $P$ is a pseudoscalar meson and $\ell$ is a charged lepton. Together with the…
The relativistic approach to electroweak properties of two-particle composite systems developed in previous work is generalized here to the case of nonzero spin. This approach is based on the use of the instant form of relativistic…
We calculate the orbital magnetization of a confined 2DEG as a function of the number of electrons in the system. Size effects are investigated by systematically increasing the area of the confining region. The results for the finite system…
Magnetic effects on free electron systems have been studied extensively in the context of spin-to-orbital angular momentum conversion. Starting from the Dirac equation, we derive a fully relativistic expression for the energy of free…
We consider finite volume effects on the electro-magnetic pion form factor near the chiral limit, in the so-called $\epsilon$ regime. The pseudoscalar-vector-pseudoscalar three-point function is calculated in the $\epsilon$ expansion of…
Linear response calculations based on the time-dependent density-functional theory are presented. Especially, we report results of the finite amplitude method which we have recently proposed as an alternative and feasible approach to the…
Electromagnetic effects in the leptonic decay rates $\pi^+ \to \mu^+ \nu$ and $K^+ \to \mu^+ \nu$ are evaluated for the first time on the lattice. Following a method recently proposed in Ref. [1] the emission of virtual photons at leading…