room 0.06, Pasteura 5 at 15:30
Prof. dr hab. Jerzy Lewandowski (Instytut Fizyki Teoretycznej Wydziału Fizyki UW)
room 0.06, Pasteura 5 at 15:30
Dr hab. Piotr Szymczak, prof. UW (Instytut Fizyki Teoretycznej Wydziału Fizyki UW)
The waves of the sea, the little ripples on the shore, the sweeping curve of the sandy bay between the headlands, the outline of the hills, the shape of the clouds, all these are so many riddles of form, so many problems of morphology, and all of them the physicist can more or less easily read and adequately solve" - wrote D'Arcy Wentworth Thompson in 1917 in his famous book "On growth and form". Modern physics has progressed along the way outlined by Thompson, discovering the principles by which multiplicity of relatively simple interactions can give rise to the emergence of organized structures or qualitatively new behaviors. In this talk, I will give two examples of self-organizing growth processes driven by the flow: the growth of "wormholes" in a dissolving rock during early stages of cave formation and the growth of seepage channels incised by groundwater flow. In particular, I will discuss the question why the initially planar fracture is dissolving in an inhomogeneous manner, leading to the appearance of karst conduits and why the tributaries of Apalachicola river in Florida join each other at an angle of 72 degrees
room 0.06, Pasteura 5 at 15:30
Prof. dr hab. Iwo Białynicki-Birula (CFT PAN)
In recent years, angular momentum has become a valuable resource that extends our ability to transmit information and also to increase the usefulness of beams in carrying various “mechanical” tasks. Even though the Maxwell and Dirac equations are well known, the description of beams has been treated with the use of approximations that have hidden important aspects of relativistic beams. In my talk, I will give a simple recipe to produce exact solutions of relativistic equations describing the photon and electron beams and I will show that these solutions exhibit intricate properties not seen in the textbook, plane wave solutions.