Ort / Place
Physik Campus Riedberg, Max-von-Laue-Str. 1, 60438 Frankfurt
Großer Hörsaal, Raum 0.111

Zeit / Time
Mittwochs / Wednesday , 16.00 Uhr c.t.



Dr. Oleksandr Tsyplyatyev
Institut für Theoretische Physik, Goethe-Universität Frankfurt

A n t r i t t s v o r l e s u n g

Interacting electrons in one dimension beyond the low energy limit

Quantum many-body phenomena fascinate physicists since the very development
of the quantum mechanics due to their richness in various branches of physics
ranging from atomic to solid-state and low temperatures. Interactions produce
strong correlations (entanglement) between quantum particles resulting in an
exponentially large Fock space and provide a huge room for a counterintuitive,
from the naïve microscopic point of view, states of matter that can emerge.
Contemporary examples that intrigue researchers nowadays include the quantum
magnets that host the unconventional spin-liquid states and the strongly-
correlated materials that undergo the phase transition to the superconducting
state already at a high temperature. While the theoretical understanding of the
quantum man-body systems is not complete at the moment, a number of the
exact solutions to specific models such as the Bethe ansatz approach to the
quantum spin chains in one dimension or the Richardson solution to the BCS
model of the conventional superconductors in a grain and some systematic
approaches in particular regimes such as the diagrammatic perturbation
technique for Green functions are already available.

In this talk, I will give an overview of the effect of interactions on the low-lying
electronic excitations in a solid body in the linear regime. Furthermore, I will
briefly present the recent progress in the nonlinear regime beyond low energy in
one dimension.



Prof. Dr. Anna Watts
University of Amsterdam

Neutron stars in the spotlight

Densities in neutron star cores can reach up to ten times the density of a normal atomic nucleus, and the stabilising effect of gravitational confinement permits long-timescale weak interactions. This generates matter that is neutron-rich, and opens up the possibility of stable states of strange matter. Our uncertainty about the nature of matter under these conditions is encoded in the Equation of State, which can be linked to macroscopic observables like mass, radius, tidal deformation or moment of inertia. One very promising technique for measuring the EOS exploits hotspots that form on the neutron star surface due to the pulsar mechanism, accretion streams, or during thermonuclear explosions in the neutron star ocean. How the spots form is not always clear, and I will discuss some of the unsolved puzzles related to spot generation. I will then explain how the hotspot technique is being used by NICER, an X-ray telescope installed last year on the International Space Station - and why the technique is a mission driver for the next, larger-area generation of telescopes. 

Rückblick Physikalisches Kolloquium:
SS 2010, WS 2010/11, SS 2011, WS 2011/12, SS 2012, WS 2012/13, SS 2013, WS 2013/14, SS 2014, WS2014/15, SS2015, WS2015/16, SS2016, WS2016/17, SS 2017, WS 2017/18, SS 2018