Kalb-Ramond backgrounds in α′-complete cosmology

We study the matter-coupled equations of motion for cosmological NS massless fields including all α′ corrections in an O(d, d) duality invariant approach, with emphasis on the Kalb-Ramond two-form field B(2) and its source. Solutions for the vacuum and matter cases are found and the corresponding Einstein frame cosmologies are discussed. We also show that the ansatz for B(2) required by the duality invariant framework implies that the two-form is non-isotropic.

Quantum motion, coherent states and geometric phase of a generalized damped pendulum

In this work, we analyze the quantum dynamics of a generalized pendulum with a time-varying mass increasing exponentially and constant gravitation. By using Lewis–Riesenfeld invariant approach and Fock states, we solve the time-dependent Schrödinger equation for this system and write its solutions in terms of solutions of the Milne–Pinney equation. We also construct coherent states for the quantized pendulum and use both Fock and coherent states to investigate some important physical proprieties of the quantized pendulum such as eigenvalues of the angular displacement and momentum, their quantum variances as well as the respective uncertainty principle. Finally, we derive the geometric, dynamical and Berry phases for the time-dependent generalized pendulum.