Date:
Mon, 15/05/201712:00-13:30
Location:
Levin building, Lecture Hall No. 8
Lecturer: Prof. Efi Efrati
Affiliation:
Department of Physics of Complex Systems,
Weizmann Institute of Science
Abstract:
When Robert Brown first observed the random motion of colloidal pollen grains in water he concluded that the motion observed arose “neither from currents in the fluid, nor from its gradual evaporation, but belonged to the particle itself”. We now know that the motion’s random nature is due to the grains' interaction with a myriad of distinct fluid constituents whose collective contributions provide the system with a stochastic driving. Such processes pervade our lives and are at the heart of novel fabrication techniques as well as cellular biological processes. In this work we study the dynamics of a classical tri-atomic molecule consisting of three masses and three harmonic springs suspended in free space that displays a rotational random walk that “belongs to the particle itself”. The geometric non-linearities arising from the non-zero rest-lengths of the springs connecting the masses suffice to break the integrability of the harmonic system and lead to chaotic dynamics in many regimes of the phase space. The non-trivial connection of the system’s shape space allows it, much like falling cats, to rotate with zero angular momentum and manifest its chaotic dynamics as an orientational random walk.
Affiliation:
Department of Physics of Complex Systems,
Weizmann Institute of Science
Abstract:
When Robert Brown first observed the random motion of colloidal pollen grains in water he concluded that the motion observed arose “neither from currents in the fluid, nor from its gradual evaporation, but belonged to the particle itself”. We now know that the motion’s random nature is due to the grains' interaction with a myriad of distinct fluid constituents whose collective contributions provide the system with a stochastic driving. Such processes pervade our lives and are at the heart of novel fabrication techniques as well as cellular biological processes. In this work we study the dynamics of a classical tri-atomic molecule consisting of three masses and three harmonic springs suspended in free space that displays a rotational random walk that “belongs to the particle itself”. The geometric non-linearities arising from the non-zero rest-lengths of the springs connecting the masses suffice to break the integrability of the harmonic system and lead to chaotic dynamics in many regimes of the phase space. The non-trivial connection of the system’s shape space allows it, much like falling cats, to rotate with zero angular momentum and manifest its chaotic dynamics as an orientational random walk.