Events
Biological and soft-matter physics
The cost of information and other mathematical biology problems
Prof. Yigal Meir
Dept. Of Physics, Ben-Gurion University Of The Negev & Dept. Of Physics, Princeton University
Thu, 06 May 2021, 12:10
ZOOM only - Meeting ID: 874 2021 0979
Abstract: In this talk I will discuss several projects in mathematical ecology and biology, such as the emergence of a finite number of ecological niches in a continuous environment and the conditions for co-existence of different species. The main part of the talk will concentrate on the strategies of phages/viruses and the cost of information about the environment they can pay in order to have an advantage over other species/strategies.
Join Zoom Meeting
https://us02web.zoom.us/j/87420210979
Meeting ID: 874 2021 0979
Particles and Fields Seminar
Catastrophic Production of Slow Gravitinos
Evan Mcdonough
University Of Chicago
Mon, 10 May 2021, 14:00
Sacta-Rashi Building for Physics (54), room 207
Abstract: In this talk I will discuss gravitational particle production of the massive spin-3/2 Rarita-Schwinger field, and its close relative, the gravitino. For masses lighter than the value of the Hubble expansion rate after inflation, there is catastrophic gravitational particle production, wherein the number of gravitationally produced particles is divergent, caused by a transient vanishing of the helicity-1/2 gravitino sound speed. In contrast with the conventional gravitino problem, the spectrum of produced particles is dominated by those with momentum at the UV cutoff. This suggests a breakdown of effective field theory, which might be cured by new degrees of freedom that emerge in the UV, i.e., in supergravity. A survey of supergravity models reveals those where the catastrophe is cured and models where it persists. Insofar as quantizing the gravitino is tantamount to quantizing gravity, as is the case in any UV completion of supergravity, the models exhibiting catastrophic production are prime examples of 4-dimensional effective field theories that become inconsistent when gravity is quantized, suggesting a link to the Swampland program. We propose the Gravitino Swampland Conjecture.
Zoom link will be sent separately.
Physics Colloquium
Quantum controlling levitated solids: a novel probe for the gravity-quantum interface
Markus Aspelmeyer
University Of Vienna
Mon, 10 May 2021, 16:10
Zoom
Abstract: The increasing level of control over motional quantum states of massive, solid-state mechanical devices opens the door to a hitherto unexplored parameter regime of macroscopic quantum physics. I will report on our recent progress towards controlling levitated solids in the quantum regime. I will discuss the prospects of using these systems for fundamental tests of physics, including the interface between quantum and gravitational physics.
*** The Zoom link will be sent to all the department members on the day of the event. ***
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