arXiv subjects

Thomas Papenbrock

Publications and source records attributed to Thomas Papenbrock.

39 records · Page 3Linked to original sources

arXiv1998

Nonergodic Behavior of Interacting Bosons in Harmonic Traps

We study the time evolution of a system of interacting bosons in a harmonic trap. In the low-energy regime, the quantum system is not ergodic and displays rather large fluctuations of the ground state occupation number. In the high energy regime of classical physics we find nonergodic behavior for modest numbers of trapped particles. We give two conditions that assure the ergodic behavior of the quantum system even below the condensation temperature.

cond-mat↗

arXiv1998

Spectral Correlations in the Crossover Transition from a Superposition of Harmonic Oscillators to the Gaussian Unitary Ensemble

We compute the spectral correlation functions for the transition from a harmonic oscillator towards the Gaussian Unitary Ensemble (GUE). We use a variant of the supersymmetry method to obtain analytical results in a fast and elegant way. In contrast to certain related transitions, the k-point correlation function possesses the k*k determinant structure of the GUE limit for the entire transition. The results are used to consider also the spectral correlations of a superposition of M transition spectra. Our results are non-perturbative and are valid for all values of the transition parameter.

chao-dyn↗

arXiv1998

Bremsstrahlung in Alpha-Decay

We present the first fully quantum mechanical calculation of photon radiation accompanying charged particle decay from a barrier resonance. The soft-photon limit agrees with the classical results, but differences appear at next-to-leading-order. Under the conditions of alpha-decay of heavy nuclei, the main contribution to the photon emission stems from Coulomb acceleration and may be computed analytically. We find only a small contribution from the tunneling wave function under the barrier.

nucl-th↗