Thema: 
Spinorbitronics: controlling magnets with electric currents 
Datum: 
18.06.18 
Uhrzeit: 
16:15 
Ort: 
H6 
Vortragender: 

ETH Zürich 

Inhalt: 
The coupling of spin and orbital angular momenta underlies the magnetoelectric properties of matter. Although small, the spinorbit interaction determines the equilibrium properties of magnets as well as the possibility to excite the magnetization out of equilibrium while ensuring the conservation of angular momentum. In this talk, I will review prominent mechanisms due to spinorbit coupling that give rise to spin currents in ferromagnetic and antiferromagnetic heterostructures, showing how unusual magnetoresistance and spin torque phenomena emerge from chargespin conversion in these materials. Finally, I will present recent results based on pumpprobe magnetooptic experiments that allow us to measure the spin Hall effect in nonmagnetic conductors and image currentinduced magnetization switching of ferromagnetic dots on a timescale of 100 ps. 
Ansprechpartner: 
Thema: 
Upper and lower Lipschitz bounds for the perturbation of edges of the essential spectrum 
Datum: 
01.06.18 
Uhrzeit: 
16:15 
Ort: 
V3204 
Vortragender: 

TU Dortmund 

Inhalt: 
Let $A$ be a selfadjoint operator, $B$ a bounded symmetric operator and $A+t B$ a perturbation. I will present upper and lower Lipschitz bounds on the function of $t$ which locally describes the movement of edges of the essential spectrum. Analogous bounds apply also for eigenvalues within gaps of the essential spectrum. The bounds hold for an optimal range of values of the coupling constant $t$. This is result is applied to Schroedinger operators on unbounded domains which are perturbed by a nonnegative potential which is mostly equal to zero. Unique continuation estimates nevertheless ensure quantitative bounds on the lifting of spectral edges due to this semidefinite potential. This allows to perform spectral engineering in certain situations. The talks is based on the preprint https://arxiv.org/abs/1804.07816 
Ansprechpartner: 
Thema: 
tba 
Datum: 
10.07.18 
Uhrzeit: 
14:15 
Ort: 
D6135 
Vortragender: 
Jens Mund 
UFJF, Juiz de Fora, Brazil 

Inhalt: 

Ansprechpartner: 
Thema: 
Impact of Eigenstate Thermalization on the Route to Equilibrium 
Datum: 
14.06.18 
Uhrzeit: 
14:15 
Ort: 
D5153 
Vortragender: 

Universität Osnabrück 

Inhalt: 
The eigenstate thermalization hypothesis (ETH) and the theory of linear response (LRT) are celebrated cornerstones of our understanding of the physics of manybody quantum systems out of equilibrium. While the ETH provides a generic mechanism of thermalization for states arbitrarily far from equilibrium, LRT extends the successful concepts of statistical mechanics to situations close to equilibrium. In our work, we connect these cornerstones to shed light on the route to equilibrium for a class of properly prepared states. We unveil that, if the odiagonal part of the ETH applies, then the relaxation process can become independent of whether or not a state is close to equilibrium. Moreover, in this case, the dynamics is generated by a single correlation function, i.e., the relaxation function in the context of LRT. Our analytical arguments are illustrated by numerical results for idealized models of randommatrix type and more realistic models of interacting spins on a lattice. Remarkably, our arguments also apply to integrable quantum systems where the diagonal part of the ETH may break down. 
Ansprechpartner: 
Thema: 
Eigenvectorrelated correlation functions and their connection with generalized chiral random matrix ensembles with a source 
Datum: 
11.01.18 
Uhrzeit: 
16:00 
Ort: 
D5153 
Vortragender: 
Jacek Grela 
LPTMS Université ParisSud 

Inhalt: 
We will introduce eigenvectorrelated correlation functions, discuss briefly their significance in dynamical Ginibre ensemble [1,2] and present asymptotic results in the large matrix size limit. Motivated by recent work [3] on joint eigenvectoreigenvalue correlation function valid for finite matrix size N in the complex and real Ginibre Ensembles, we study integrable structure of a certain generalized chiral Gaussian Unitary Ensemble with a source [4]. This model can be also interpreted as a deformation of the complex Ginibre Ensemble with an external source with additional determinant term. We present compact formulas for the characteristic polynomial, inverse characteristic polynomial and the kernel. In the case of a special source, we calculate asymptotics in the joint "bulkedge" regime of all aforementioned objects and show their Besseltype behaviour. References: [1] ''Dysonian dynamics of the Ginibre ensemble'', Z. Burda, J. Grela, M. A. Nowak, W. Tarnowski, P. Warcho?, Phys. Rev. Lett. 113, 104102 (2014) [2] ''Unveiling the significance of eigenvectors in diffusing nonhermitian matrices by identifying the underlying Burgers dynamics'', Z. Burda, J. Grela, M. A. Nowak, W. Tarnowski, P. Warcho?, Nucl. Phys. B 897, 421 (2015) [3] ''On statistics of biorthogonal eigenvectors in real and complex Ginibre ensembles: combining partial Schur decomposition with supersymmetry'', Y. V. Fyodorov, arXiv:1710.04699 [4] ''On characteristic polynomials for a generalized chiral random matrix ensemble with a source", Y. V. Fyodorov, J. Grela, E. Strahov, arXiv:1711.07061 
Ansprechpartner: 
Thema: 
The Random Normal Matrix Model: Insertion of a Point Charge 
Datum: 
27.06.18 
Uhrzeit: 
16:15 
Ort: 
V3201 
Vortragender: 

Lund University 

Inhalt: 
We study conditional twodimensional loggases in the determinantal case, given that there is a point charge in the interior of the support of the equilibrium measure (the ''droplet''). On a microscopic level, we obtain near the inserted charge a family of universal pointfields, depending on the strength of the charge and so on, which are characterized by special entire functions  MittagLeffler functions. The charge also affects the microscopic behaviour near the boundary of the droplet, where it gives rise to a kind of balayage operation. One motivation for studying this kind of conditional pointprocesses is that they are closely related to the characteristic polynomial of a random normal matrix  an object of interest for field theories and multiplicative chaos. The talk is based on joint work with Kang and Seo. 
Ansprechpartner: 