HIP NEWS June 6th 2016
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HIP Staff News
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Dr. Antti Väihkönen will start as HIP Research Coordinator on August 1st. He is moving to HIP from the Academy of Finland.
DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS
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Monday 6 June 2016 at 10.15 in A315
Juan Pedraza (Amsterdam) (Note day!)
Spread of entanglement in holographic theories
Abstract: In this talk I will present recent results of the propagation of entanglement entropy after a global quench in the context of AdS/CFT. I will start by reviewing the heuristic picture for entanglement propagation dubbed as ‘entanglement tsunami’, and explain why this interpretation fails for general theories and entangling regions. In the second part of the talk I will present an analytic perturbative calculation for small subregions and show that in this regime the spread of entanglement exhibit some distinct features: i) the instantaneous rate of growth is not constrained by causality, but rather its time average, and ii) the saturation is always continuous, regardless the shape of the entangling region. I will also comment on the generalization of these results for non-relativistic scale invariant theories in some generic examples (1602.05934).
Tuesday 7 June 2016 at 10.15 in A315
Ilpo Vattulainen (Helsinki)
Cholesterol, tiny but tough! How membranes sense changes in cholesterol structure.
Abstract: Cholesterol is one of the vital components in regulating the physical properties of animal cell membranes. Further, there are membrane proteins whose function is dependent on cholesterol, however the mechanisms and physical principles used by cholesterol to modulate protein function remain unknown. What makes cholesterol exceptionally intriguing is the fact that other sterols are not able to replace cholesterol, thus its structure is unique in a manner that is not yet understood. In this talk, we discuss how cell membranes sense cholesterol and changes in its structure. We consider synthetic sterols non-existent in nature to elucidate the roles of cholesterol’s individual structural elements. This brings out the critical components in cholesterol structure that are critical to its function. To clarify how reactive oxygen species affect cholesterol and its role in cell function, we also discuss how oxysterols based on oxidation of cholesterol affect membrane properties that turn out to be distinct from those induced by cholesterol. We further discuss how cholesterol is able to govern cellular signaling by modulating the structure and dynamics of membrane receptors that manage the signaling between the outside and the inside of cells. The data emerged from molecular simulations as well as experiments provide a basis to better understand why cholesterol is indeed unique in modulating membrane properties and membrane protein function, and the insight found by simulations can possibly be used to predict new synthetic sterols with applications in biotechnology.
Thursday 9 June 2016 at 14.15 in A315
Kai Schmidt-Hoberg (Desy) (Note time!)
The case for dark matter self interactions – evidence in Abell 3827?
Abstract: I will review motivations for the existence of self interacting dark matter and discuss possible astrophysical observables. Self-interactions of dark matter particles can potentially lead to an observable separation between the dark matter halo and the stars of a galaxy moving through a region of large dark matter density. Such a separation has recently been observed in a galaxy falling into the core of the galaxy cluster Abell 3827. I discuss the DM self-interaction cross section needed to reproduce the observed effects.
Upcoming Events: Nuclear Science and Technology Symposium – NST2016
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The Finnish Nuclear Society (FNS) organizes the Nuclear Science and
Technology Symposium – NST2016 on November 2-3, 2016 in Helsinki. The
symposium gathers together research, industry and authority
representatives from Finland and abroad for scientific talks and
industry presentations. The FNS 50-year anniversary dinner and lectures
for the general public are held in connection with the symposium. For
details see the webpage http://www.ats-fns.fi/en/nst2016.
Visitors
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P. Dendooven 6.6.-9.6. ; 20.6.-8.7.
B.S. DiNunno 1.6. – 3.7. (NJ)
C. Carlson 31.5.-15.6. (MS)
M. Hindmarsh 29.4. – 12.6. (KR)
A. Lopez 29.4. – 13.6. (MH, KR)
J. Pedraza 1.6. – 7.6. (NJ)