The Quantum Chaos Group 

Highlights  
Dynamics of condensed particles in a few site system ()
The physics of bosons in an site system is described by the BoseHubbard Hamiltonian. The problem is integrable and equivalent to spin problem, while the problem has both nontrivial topology and mixed phase space. Our studies concerns the analysis of fluctuations, occupation statistics and quantum stirring in such systems.
The time dependent dynamics in a Bosonic Josephson junction with no driving can be regarded as a quantum version of a pendulum. Adding driving to this system, we have studied the adiabaticdiabaticsudden crossover of the manybody LandauZener dynamics; the Kapitza pendulum dynamics; and the Quantum Zeno dynamics due to erratic driving. In particular we have studied the stabilization and the suppression of collisioninduced dephasing by periodic, erratic, or noisy driving. The problem is the minimal configuration for the study of quantum thermalization and manybody localization. Specifically we consider the equilibration of the occupation in a weakly coupled subsystems. Fig1: From left to right: (a) The Wigner function of a prepared Fock state. The red dashed line is the separatrix. (b) The same, viewed from the right, after a finite time evolution. Fig2: From left to right: (a) The time evolution of the Bloch vector for various coherent preparations. (b) The quantum Zeno effect for Pi preparation due to the presence of noise. Fig3: Phase space tomography for a kickedtop: the participation number for all coherent preparations is imaged for an integrable phasespace (left), for a mixed phasespace (middle) and for a chaotic phasespace (right). In the latter case one observes the effect of scarring. For references click here 

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