| Friday 19 April 2024 | |
| Events for day: Wednesday 07 September 2022 |
| 11:00 - 12:00 Wednesday Weekly Seminar - meeting Strong and weak coupling limit of U(1) lattice model in fourier basis School PARTICLES AND ACCELERATORS Abstract: The transfer-matrix of the U(1) lattice gauge theory is investigated in the field Fourier space, the basis of which consists of the quantized currents on lattice links. In the strong coupling limit, a series expansion is developed for the elements of the transfer matrix, to which a diagrammatic representation based on the occurrence of virtual link and loop currents can be associated. Either by interpretation or through their role in fixing the relevant terms, the diagrams are reminiscent of the Feynman ones of the perturbative small coupling expansions. The issues of Gauss law constraint and gauge invariant states ar ... 14:00 - 15:00 Weekly Seminar Resonant photovoltaic effect of two-dimensional spin-3/2 hole systems School NANO SCIENCES The resonant photovoltaic effect (RPE) is a second-order nonlinear optical effect that converts light into electrical current. The non-linear optical transition occurs between heavy-hole (HH) and light-hole (LH) bands with Td-symmetry in a triangular quantum well (QW). The magnitude of RPE peak can be tuned by the momentum relaxation time and electric field. We also derive the Rashba spin-orbit coupling that is generated by electric-dipole coupling for LH and HH states. It is found that GaAs QWs can be employed as the basis for a terahertz photo-detector To join the webinar, please follow this link and log in as a guest: 19:00 - 20:30 Webinar Perception is non-conceptual School COGNITIVE SCIENCES Abstract : This talk will argue that the reason that perception is fundamentally different from cognition is that perception is non-conceptual whereas cognition is conceptual. I will review evidence that infants between the ages of 6 and 11 months can see colors but cannot accomplish even the simplest kinds of cognition involving colors. Children of the same ages can see shapes and also exhibit cognition with shape concepts. I will argue that the upshot is that color perception of these infants is non-conceptual and that one can extrapolate from this finding to all of perception. ... |