לוח שנה משולב

Ranny Budnik
"Exploring the dark side with bright, pure crystals“
Dark matter surrounds us and passes through us, yet it has not been discovered, after over a decade of intense efforts. However, many "windows" to dark matter parameter space remain closed, and opening them has become a leading target for the particle cosmology community. I will go quickly through the basics of dark matter, detection methods and recent results, and present an effort we are pursuing in our lab at the Weizmann Institute, to develop a new type of detector, able to detect low mass dark matter, using rare defects in pure crystals.

Oren Raz
"Anomalous thermal relaxation: from your kitchen to trapped ions“

Take a cold system, and couple it to a hot environment. Evidently, the system will heat up. Surprisingly, many aspects of this common process are poorly understood. Examples range from the anomalous heating rate in trapped ions, where the observed heating rate is commonly three orders of magnitude higher than naively expected, to a "thermal overshoot" where the system's temperature, during the relaxation process, becomes higher than the environment's temperature.

Binghai Yan

“The history and new understanding of surface states”

"A story about the electronic state on the surface, from the Shockley state to the topological state."

Coherent Pulsed Laser Experiments on Light Harvesting Systems such as FMO and P645, as well as on Light-Induced Isomerization in visual photoreceptors such as retinal, have suggested a role for light-induced quantum coherences in Biology. We introduce the issues and show, using analytically soluble models, that such coherences will not occur in natural environments, where the turn-on time of the radiation is long
and the light is incoherent. However, stationary coherences related to the open system character of such systems may well prove significant, both in Biology and in the design of efficient solar-driven devices. In addition, we show that time scales for processes such as retinal isomerization in nature are a billion times longer than the femtosecond time scales suggested by pulsed laser experiments.

Drug addiction is a chronically relapsing disorder characterized by compulsive drug use despite catastrophic personal consequences (e.g., loss of family, job) and even when the substance is no longer perceived as pleasurable. In this talk, I will present results of human neuroimaging studies, utilizing a multimodal approach (neuropsychology, functional magnetic resonance imaging, event-related potentials recordings), to explore the neurobiology underlying the core psychological impairments in drug addiction (impulsivity, drive/motivation, insight/awareness) as associated with its clinical symptomatology (intoxication, craving, bingeing, withdrawal). The focus of this talk is on understanding the role of the dopaminergic mesocorticolimbic circuit, and especially the prefrontal cortex, in higher-order executive dysfunction (e.g., disadvantageous decision-making such as trading a car for a couple of cocaine hits) in drug addicted individuals. The theoretical model that guides the presented research is called iRISA (Impaired Response Inhibition and Salience Attribution), postulating that abnormalities in the orbitofrontal cortex and anterior cingulate cortex, as related to dopaminergic dysfunction, contribute to the core clinical symptoms in drug addiction. Specifically, our multi-modality program of research is guided by the underlying working hypothesis that drug addicted individuals disproportionately attribute reward value to their drug of choice at the expense of other potentially but no-longer-rewarding stimuli, with a concomitant decrease in the ability to inhibit maladaptive drug use. In this talk I will also explore whether treatment (as usual) and 6-month abstinence enhance recovery in these brain-behavior compromises in treatment seeking cocaine addicted individuals. Promising neuroimaging studies, which combine pharmacological (i.e., oral methylphenidate, or RitalinTM) and salient cognitive tasks or functional connectivity during resting-state, will be discussed as examples for using neuroimaging in the empirical guidance for the development of effective neurorehabilitation strategies (including cognitive training) in drug addiction.

The "active" aspect of active matter, from the statistical-physics perspective, is the breaking of detailed balance in the microscopic dynamics. Hence, modelling of nonequilibrium microscopic conditions and their implications, such as the appearance of emergent equilibrium, is now active as a field of research. Recent theory studies and experiments with ultracold ions trapped in vacuum, make surprising contact with these questions;
A fundamental model of transport in a noisy environment is that of the Brownian ratchet, or Brownian motor. It models the emergence of nonvanishing currents in a noisy system despite the vanishing of the mean force. Crucially based on symmetry breaking, it is a basic model for some of the physics underlying, e.g., biological molecular motors. I will discuss self-organized ion crystals featuring transport of ratchet-like discrete solitons. The rate and direction of selective topological-charge transport can be described as a Kramer's escape applied to a collective coordinate, with an emergent effective temperature [1].
If time permits, I will briefly discuss other relevant physics encountered with trapped ions - stochastic dynamics with single ions [2], and the simulation of microscopic friction models [3].

[1] J. Brox, P. Kiefer, M. Bujak, T. Schaetz (experiment), H. Landa (theory), PRL 119, 153602 (2017).
[2] V. Roberdel, A. Maitra, D. Leibfried, D. Ullmo, and H. Landa, in preparation.
[3] T. Fogarty, C. Cormick, H. Landa, V. M. Stojanović, E. Demler, and G. Morigi, PRL 115, 233602 (2015).

Increasing evidence indicates that the brain can control immunity. But how is the brain informed of the state of the immune response? What information is available to the brain regarding the immune system, and how do these essential systems communicate and interact? In this talk, I will try to bridge these gaps. I will demonstrate how specific activity in the brain affects the immune response, and how the peripheral nervous system can convey signals from the brain to the periphery to regulate immunity.