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Helmut Kroeger

Publications and source records attributed to Helmut Kroeger.

3 recordsLinked to original sources

Does the 1/f frequency-scaling of brain signals reflect self-organized critical states?

Many complex systems display self-organized critical states characterized by 1/f frequency scaling of power spectra. Global variables such as the electroencephalogram, scale as 1/f, which could be the sign of self-organized critical states in neuronal activity. By analyzing simultaneous recordings of global and neuronal activities, we confirm the 1/f scaling of global variables for selected frequency bands, but show that neuronal activity is not consistent with critical states. We propose a model of 1/f scaling which does not rely on critical states, and which is testable experimentally.

q-bio.NC

Quantum chaos and regularity in $Φ^4$ theory

We check the eigenvalue spectrum of the $Φ^{4}_{1+1}$ Hamiltonian against Poisson or Wigner behavior predicted from random matrix theory. We discuss random matrix theory as a tool to discriminate the validity of a model Hamiltonian compared to an analytically solvable Hamiltonian or experimental data.

hep-lat

Improving the Lattice QCD Hamiltonian

Improvement of the Hamiltonian in lattice gauge theory is considered. We give explicit expressions for classical improvement and discuss also quantum corrections.

hep-lat