Reliability of genetic networks is evolvable

Control of the living cell functions with remarkable reliability despite the stochastic nature of the underlying molecular networks -- a property presumably optimized by biological evolution. We here ask to what extent the property of a stochastic dynamical network to produce reliable dynamics is an evolvable trait. Using an evolutionary algorithm based on a deterministic selection criterion for the reliability of dynamical attractors, we evolve dynamical networks of noisy discrete threshold nodes. We find that, starting from any random network, reliability of the attractor landscape can often be achieved with only few small changes to the network structure. Further, the evolvability of networks towards reliable dynamics while retaining their function is investigated and a high success rate is found.Comment: 5 pages, 3 figure

Double diffractive rho-production in gamma^* gamma^* collisions

We present a first estimate of the cross-section for the exclusive process gamma^*_L (Q_1^2) gamma^*_L(Q_2^2) -> rho^0_L rho^0_L, which will be studied in the future high energy e^+ e^- linear collider. As a first step, we calculate the Born order approximation of the amplitude for longitudinally polarized virtual photons and mesons, in the kinematical region s >> -t, Q_1^2, Q_2^2. This process is completely calculable in the hard region Q_1^2, Q_2^2 >> Lambda^2_{QCD}. We perform most of the steps in an analytical way. The resulting cross-section turns out to be large enough for this process to be measurable with foreseen luminosity and energy, for Q_1^2 and Q_2^2 in the range of a few GeV^2.Comment: 25 pages, 5 figures. Published version in EPJC. Minor changes and several references added with respect to v

The C-Odd Four-Gluon State in the Color Glass Condensate

The study of the perturbative Odderon at high gluon densities in the color glass condensate requires to take into account states with more than three gluons. We formulate evolution equations for these states in which the number of gluons is not fixed during the evolution. We further determine the coupling of these Odderon states to the gamma to eta_c impact factor for arbitrary numbers of gluons. We find an exact solution of the evolution equation for the four-gluon Odderon state in terms of the three-gluon Odderon state. It is shown that a similar solution exists also for a different class of Odderon solutions which does not couple to the gamma to eta_c impact factor. We discuss the implications of our result from the perspective of constructing an effective field theory of reggeized gluons for the color glass condensate.Comment: 32 pages; v2: references, comments and one equation adde

γ∗γ∗→ρρ\gamma ^* \gamma ^* \to \rho \rho at very high energy

The next generation of $e^+e^-$-colliders will offer a possibility of clean testing of QCD dynamics in the Regge limit. Recent progress in the theoretical description of exclusive processes permits for many of them a consistent use of the perturbative QCD methods. We advocate that the exclusive diffractive production of two $\rho$ mesons from virtual photons at very high energies should be measurable at the future linear collider (LC).Comment: 4 pages, 2 figures, talk given at the conference Baryon 0