Biological and Soft Matter Physics
Nonlinear Dynamics and Biological Applications
Arik Yochelis
Simulation of waves in a model for intra-cellular actin polymerization and membrane ruffles
Biological systems show a plethora of fascinating self-organized behaviors that range from organ to cellular levels, such as spiral waves, pulses, synchronization, and steady states that are periodic in space. These non-equilibrium phenomena emerge through either spontaneous or forced symmetry breaking mechanisms. Employing nonlinear dynamics methods, we attempt to understand specific cases (localized waves in the inner ear) as well as gain general insights into the emergence of traveling waves with motivation taken from molecular motors, actin polymerization and cardiac system.
Condensed Matter Theory
Disordered Systems
Yevgeny Bar Lev
Characterization of the anomalous ergodic phase, leaves many questions open.
Disorder allows avoiding thermalization and defy conventional statistical mechanics, through the mechanisms of Anderson or many-body localization. We study these ergodicity breaking mechanisms in detail. In particular the nature of transport and correlations spreading in systems on the verge of localization.
Atomic, Molecular and Optical Physics
Quantum Cheshire Cat
Daniel Rohrlich
If D1 clicks, then intermediate measurements find the Cat (photon) in |L> while its grin (polarization) is nonzero only in |R>.
Y. Aharonov, S. Popescu, D. Rohrlich and P. Skrzypczyk, "Quantum Cheshire Cats", New J. Phys. 15 (2013) 113015. We present a quantum Cheshire Cat. Weak measurements on a pre- and post-selected ensemble find the Cat in one place and its grin in another. The Cat could be a photon, with circular polarization as its quantum "grin" state. But see T. Denkmayr et al., "Observation of a quantum Cheshire Cat in a matter-wave interferometer experiment", Nat. Comm. 5, 4492 (2014); they send neutrons through a silicon crystal interferometer, while weakly probing their locations and magnetic moments. The results suggest that the neutrons go along one beam path while magnetic moments go along the other.
Astrophysics and Cosmology
Black Holes
Uri Keshet
Stellar trajectories around SgA*, the central black hole of the Milky Way
Black holes play a dual role in physics, both as astronomical objects routinely discovered nowadays in binaries and in galactic centers, and as basic elements in quantum gravity. The presence of a supermassive black hole in the center of our own galaxy is evident from the trajectories of stars around a small region known as SgA* (see movie). We study black holes such as the one hiding in SgA*, and their dense stellar environment.
High-Energy Physics
Fluid-Gravity Correspondence
Michael Lublinsky
Illustration of a collision of two gold nuclei at RHIC.
Quark Ggluon Plasma (QGP) is created in Heavy Ion Collisions at the Relativistic Heavy Ion Collider (RHIC) and LHC. A striking discovery of RHIC is that QGP produced there is strongly coupled and behaves like a nearly perfect fluid with relativistic hydrodynamics being an appropriate description of the observed phenomena. Remarkably, hydrodynamical properties of QGP could be studied using gravitational theory of Black Holes in curved five-dimensional spaces. The fluid/gravity correspondence relates graviton`s absorption by a Black Hole to dissipation taking place in the QGP.
Condensed Matter Experimental
Mechanical properties on the nm scale
Yishay Manassen
Strain map from Gd islands and Local young modulus of nanoparticles.
The scanning tunneling microscope is a device capable of observing an image with atomic resolution and is capable of observing physical phenomena on the atomic scale. In this study we are interested in the nm scale mechanical properties, normally studied macroscopically, which can vary in different locations on the surface. These properties are the stress and strain tensors, the elastic constants, the surface energy and stress. These values can be measured either using a external perturbation (the STM tip) or internal perturbation (a heteroepitaxial island, chemical reaction).