The title ‘Chiral extrapolations’ of this contribution refers more precisely to chiral extrapolations of lattice QCD data. We shall deal with low-energy aspects of QCD, which are not accessible to ordinary weak-coupling perturbation theory. Possible alternatives to weak-coupling perturbation theory in the low-energy domain of QCD include the investigation of specific models, Monte Carlo simulat...

A variational approach is proposed to determine some properties of the adiabatic Holstein-Hubbard model which describes the interactions between a static atomic lattice and an assembly of fermionic charge carriers. The sum of the electronic energy and the lattice elastic energy is proved to have minima with a polaron structure in a certain domain of the phase diagram. Our analytical work consis...

We formulate a new framework in lattice QCD to study the relevant energy scale of QCD phenomena. By considering the Fourier transformation of link variable, we can investigate the intrinsic energy scale of a physical quantity nonperturbatively. This framework is broadly available for all lattice QCD calculations. We apply this framework for the quark-antiquark potential and meson masses in quen...

Classical lattice spin systems provide an important and illuminating family of models in statistical physics. An interaction on a lattice L ⊂ Z determines a lattice spin system with potential A . The pressure P(A ) and free energy FA (β) = −(1/β)P (βA ) are fundamental characteristics of the system. However, even for the simplest lattice spin systems, the information about the potential that th...

Blackbody radiation BBR shifts of the P0S0 clock transition in the divalent atoms Mg, Ca, Sr, and Yb are evaluated. The dominant electric-dipole contributions are computed using accurate relativistic many-body techniques of atomic structure. At room temperatures, the resulting uncertainties in the E1 BBR shifts are large and substantially affect the projected 10−18 fractional accuracy of the op...

The leading order low energy parameters like the pion decay constant or the quark condensate are well-known from “classical” low energy theorems and experiments. It is a challenge, however, to find these parameters based exclusively on an ab-initio QCD calculation. We discuss results of a quenched lattice calculation of low energy constants using the chirally improved Dirac operator. Several la...

The leading order low energy parameters like the pion decay constant or the quark condensate are well-known from “classical” low energy theorems and experiments. It is a challenge, however, to find these parameters based exclusively on an ab-initio QCD calculation. We discuss results of a quenched lattice calculation of low energy constants using the chirally improved Dirac operator. Several la...

A square-cell lattice is considered consisting of point masses at its knots connected by linearly elastic bonds of nonzero density. Steady-state crack propagation is studied. A general relation between the knot mass and the bond mass is assumed; however, a detailed analytical examination is made for the material-bond lattice with no concentrated masses. It is assumed that the crack divides the ...

Lattice protein models are well studied abstractions of globular proteins. By discretizing the structure space and simplifying the energy model over regular proteins, they enable detailed studies of protein structure formation and evolution. But even in the simplest lattice protein models, the prediction of optimal structures is computationally hard. Therefore, often heuristic approaches are ap...

The spectrum of baryons containing three b quarks is calculated in nonperturbative QCD, using the lattice regularization. The energies of ten excited bbb states with J = 1 2 + , 3 2 + , 5 2 + , 7 2 + , 1 2 − , and 3 2 − are determined with high precision. A domain-wall action is used for the up-, downand strange quarks, and the bottom quarks are implemented with NRQCD. The computations are done...