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.
Biological and Soft Matter Physics
Dynamics of Complex Fluids and Geophysical Flows
Roiy Sayag
Experiment of polymer solution flowing radially under weak friction
The front of a fluid that displaces a less viscous fluid in shear-dominated flows is known to be stable. We show that in predominantly extensional flows on a sphere, a similar front of a strain-rate-softening fluid can become unstable and evolve fingerlike patterns comprised of rifts and tongues. The number of rifts and tongues declines with time and is selected by competition between interfacial hoop stress, geometric stretching, momentum dissipation, and spatial curvature. Our results elucidate fracture dynamics in complex fluids under extension and are applicable to a wide range of systems, including planetary-scale ice shelves as in snowball epochs and icy moons.
Atomic, Molecular and Optical Physics
Attosecond Science and Nanophotonics Lab
Eugene Frumker
We are setting up a brand-new research laboratory of Attosecond Science and Nanophotonics in the Physics Department of the Ben-Gurion University. In our group, we focus on both experimental and theoretical studies at the interface of ultrafast nonlinear optics, attosecond science and nanoscience. More specifically, our work involves generation, measurement and control of the interaction of light and matter in atoms, molecules and nanosystems in space and time at extremely short (attosecond=10^(-18)sec) time scales. Our interests range from fundamental physical phenomena to applications.
Condensed Matter Theory
Topological Supercoductors and Majorana Fermions
Eytan Grosfeld
Majorana fermion based superconducting qubit
We are interested in properties of topological superconductors, a fascinating state of matter that could be harnessed to create a new type of quantum computer [E. Ginossar and E. Grosfeld, Nature Communications 5, 4772 (2014), Tunability of microwave transitions as a signature of coherent parity mixing effects in the Majorana-transmon qubit.]
Astrophysics and Cosmology
The largest objects: galaxy clusters
Uri Keshet
The Perseus cluster core (Chandra) with highlighted spiral cold fronts and X-ray cavities.
Galaxy clusters, as the largest virialized objects ever to form in the Universe, link cosmology and astrophysics. These 'island-universe' objects are mainly composed of dark matter and a hot, dilute plasma. Their stability is an open question, as the strong X-ray emission should have naively led to catastrophic cooling and collapse. Over the past decade, mysterious spiral structures were found in practically all clusters. They may be driven by the giant black hole lurking in the center of every cluster, for example through the relativistically hot bubbles it injects into the plasma (figure).
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).