Welcome to the Zwerger group
Welcome to the theory group led by Prof. Wilhelm Zwerger at the Physik-Department of the Technical University in Munich (TUM). Research in our group is focused on quantum and statistical physics in a wide range of areas, from condensed matter physics and nanostructures to ultracold gases and the interface between quantum optics, quantum information and solid state physics. We are working in collaboration with a number of groups in the Munich area and beyond, in particular with the Max-Planck-Institute for Quantum Optics (MPQ) and within the Nano-Inititative Munich (NIM).
News
October 2011
PRL Editors' Suggestions: Quantum capillary waves at the superfluid-Mott insulator interface
We discuss quantum fluctuations of the interface between a
superfluid and a Mott-insulating state of ultracold atoms in a
trap. The fluctuations of the boundary are due to a new type of
surface modes, whose spectrum is similar - but not identical - to
classical capillary waves. The corresponding quantum capillary
length sets the scale for the penetration of the superfluid into the
Mott-insulating regime by the proximity effect and may be on the
order of several lattice spacings. It determines the typical
magnitude of the interface width due to quantum fluctuations, which
may be inferred from single-site imaging of ultracold atoms in an
optical lattice.
Steffen
Patrick Rath, Boris Spivak, and Wilhelm Zwerger, Phys. Rev. Lett 107, 155703 (2011)
March 2011
Phonon-tunnelling dissipation in mechanical resonators
Microscale and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example, in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavours. Their performance is in many cases limited by the deleterious effects of mechanical damping. In this study, we report a significant advancement towards understanding and controlling support-induced losses in generic mechanical resonators...
Garrett D. Cole, Ignacio Wilson-Rae, Katharina Werbach, Michael R. Vanner, and Markus Aspelmeyer,
Nature Communications 2, 231 (2011).
Press release
September 2010
Viscosity and Scale Invariance of the Unitary Fermi Gas
The unitary Fermi gas, a scale invariant quantum fluid,
appears to be the most perfect non-relativistic fluid that
exists in nature: the ratio between its shear viscosity and
the entropy density exhibits a minimum near the superfluid transition
temperature, whose value is larger than the string theory bound
ℏ/4πkB by a factor of about seven.
Tilman Enss, Rudolf Haussmann, and
Wilhelm Zwerger,
Annals of Physics 326, 770–796 (2011).