The dynamical differential forms of the Klein—Gordon field

We classify the conserved currents for the Klein-Gordon field. We show that there are many which are not associated with invariances of the Lagrangian.     

Translation,dilatation, Lorentz invariant two-particle interactions

The existence of an infinite number of symmetric two-particle interactions is shown. These interactions are translation invariant, Lorentz invariant, and lead to second-order differential equations. Examples are analytic.     

Corrected Sommerfeld-Wilson rule in geometric quantization

A systematic correction to the geometric quantum conditions of Bohr, Sommerfeld, Wilson, Einstein, and Brillouin is given, which provides the extra $\text{1}\text{2}$ for the harmonic oscillator without disturbing the values they give for the hydrogen atom.     

Excited-state relaxation of Ag8 clusters embedded in helium droplets

Neutral silver clusters Ag(N) are grown in ultracold helium nanodroplets. By exploiting a strong absorption resonance recently found for Ag8, first photoelectron spectra of this neutral species are recorded. Variation of the laser photon energy reveals that direct vertical two-photon ionization is hindered by rapid relaxation into the lower edge of a long-living excited state manifold. The analysis of the dynamics gives a precise value of (6.89+/-0.09) eV for the vertical ionization potential of Ag8. The influence of the helium matrix on photoemission is discussed.     

QCD dirac operator at nonzero chemical potential: lattice data and matrix model

Recently, a non-Hermitian chiral random matrix model was proposed to describe the eigenvalues of the QCD Dirac operator at nonzero chemical potential. This matrix model can be constructed from QCD by mapping it to an equivalent matrix model which has the same symmetries as QCD with chemical potential. Its microscopic spectral correlations are conjectured to be identical to those of the QCD Dirac operator. We investigate this conjecture by comparing large ensembles of Dirac eigenvalues in quenched SU(3) lattice QCD at a nonzero chemical potential to the analytical predictions of the matrix model. Excellent agreement is found in the two regimes of weak and strong non-Hermiticity, for several different lattice volumes.