Learn More
Amblyopic sensitivities to spatial distortions of compound gratings and checker-board textures were studied. Iso-energy target signals were used by employing phase modulations which leave the stimulus power spectra unaltered. The non-amblyopic eyes of the 6 amplyopes tested showed supranormal sensitivities at 1 s exposure duration for both types of(More)
We compute the nucleon matrix elements of QCD operators of twist 3 and 4 in the instanton vacuum. We consider the operators determining 1/Q 2 –power corrections to the Bjorken, Ellis–Jaffe and Gross–Llewellyn-Smith sum rules. The nucleon is described as a soliton of the effective chiral theory derived from instantons in the 1/N c –expansion. QCD operators(More)
We observe transport of electrons through a metallic island on the tip of a nanomechanical pendulum. The resulting tunneling current shows distinct features corresponding to the discrete mechanical eigenfrequencies of the pendulum. We report on measurements covering the temperature range from 300 down to 4.2 K. We explain the I-V curve, which unexpectedly(More)
We study the off-forward quark distributions (OFQD's) in the chiral quark-soliton model of the nucleon. This model is based on the large-N c picture of the nucleon as a soliton of the effective chiral lagrangian and allows to calculate the leading twist quark– and antiquark distributions at a low normalization point. We demonstrate the consistency of the(More)
  • D I Diakonov, M V Polyakov, C Weiss
  • 1996
We propose a method to evaluate hadronic matrix elements of QCD gluon operators in the instanton vacuum. We construct the ground state of the interacting instanton ensemble for non-zero ϑ–angle using a variational principle. A method to study the ϑ–dependence of observables on the lattice is suggested. We then derive the effective fermion action, which(More)
Motivated by recent experiments, we calculate both the average current and the current fluctuations for a metallic island which oscillates between two symmetric electrodes. Electrons can only tunnel on or off the island when it is close to one of the electrodes. Using a Master equation we investigate the accuracy of such an electron shuttle both(More)
We study the non-forward matrix elements of twist–2 QCD light–ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly including all twist–2 structures in the double distribution representation, which naturally leads to a " two–component "(More)
The 1/N c –expansion of QCD suggests large flavor asymmetries of the polarized antiquark distributions in the nucleon. This is confirmed by model calculations in the large–N c limit (chiral quark–soliton model), which give sizable results for ∆¯ u(x)− ∆ ¯ d(x) and ∆¯ u(x)+ ∆ ¯ d(x)− 2∆¯ s(x). We compute the contributions of these flavor asymmetries to the(More)
We compute in the instanton vacuum the nucleon matrix elements of the twist–4 QCD operators describing power corrections to the second moments of the unpolar-ized structure functions, F L and F 2. Our approach takes into account the leading contribution in the packing fraction of the instanton medium, ¯ ρ/ ¯ R ≪ 1. Paramet-rically leading are the matrix(More)