Integrated Calendar

In trying to understand quantum gravity at a fundamental level, one of the most confusing questions is where the degrees of freedom are. So-called holographic dualities help with this question, by showing that certain quantum gravity theories are equivalent to conventional quantum field theories, in which we understand in principle where the degrees of freedom are and how they interact. Using such dualities, a new way of understanding entanglement in quantum gravity, involving so-called “bit threads”, has recently been developed. From this point of view, space becomes a channel for carrying entanglement of fundamental degrees of freedom. We will explain what holographic dualities are, what bit threads are, and what they might tell us about the nature of space in quantum gravity.

Denise Cai:
Linking memories across time
The compilation of memories, collected and aggregated across a lifetime defines our human experience. My lab is interested in dissecting how memories are stored, updated, integrated and retrieved across a lifetime. Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. Using in vivo calcium imaging (with open-source Miniscopes in freely behaving mice), TetTag transgenic system, chemogenetics, electrophysiology and novel behavioral designs, we tested how hippocampal networks temporally link memories. Multiple convergent findings suggest that contextual memories encoded close in time are linked by directing storage into overlapping hippocampal ensembles, such that the recall of one memory can trigger the recall of another temporally-related memory. Alteration of this process (e.g. during aging, PTSD, etc) affect the temporal structure of memories, thus impairing efficient recall of related information.

Tristan Shuman:
Breakdown of spatial coding and interneuron synchronization in epileptic mice
Temporal lobe epilepsy causes severe cognitive deficits yet the circuit mechanisms that alter cognition remain unknown. We hypothesized that the death and reorganization of inhibitory connections during epileptogenesis may disrupt synchrony of hippocampal inhibition. To test this, we simultaneously recorded from CA1 and dentate gyrus (DG) in pilocarpine-treated epileptic mice with silicon probes during head-fixed virtual navigation. We found desynchronized interneuron firing between CA1 and DG in epileptic mice. Since hippocampal interneurons control information processing, we tested whether CA1 spatial coding was altered in this desynchronized circuit using a novel wire-free Miniscope. We found that CA1 place cells in epileptic mice were unstable and completely remapped across a week. This place cell instability emerged ~6 weeks after status epilepticus, well after the onset of chronic spontaneous seizures and interneuron death. Finally, our CA1 network model showed that desynchronized inputs can impair information content and stability of CA1 place cells. Together, these results demonstrate that temporally precise intra-hippocampal communication is critical for spatial processing and hippocampal desynchronization contributes to spatial coding deficits in epileptic mice.

Many planetary bodies experience tides, which produce time-varying stresses. Seismic activity on the Moon is modulated by tides, and there are hints of similar effects on Earth (but not, so far, Mars).
In this talk I'll describe two other places where tides modulate geological activity at different periods: Io, a highly volcanic moon of Jupiter; and Enceladus, a small icy moon of Saturn. In both cases we can use remote-sensing observations of the modulation to make inferences about the properties of these bodies' interiors. One could imagine similar approaches being used for tidally-distorted exoplanets (e.g. the TRAPPIST system).

In this talk, we consider a model of 2d one component plasma, i.e. a gas of identical negatively charged particles. These charges are at equilibrium at inverse temperature B in an external containing potential created by a positive charge smeared over the two dimensional plane. For specific potentials and temperatures, this problem is connected to the study of eigenvalues of non-Hermitian random matrices, to the quantum fluctuations of fermions in a rotating harmonic trap or in a Laughlin state. We study the extreme value statistics for this system as well as the full counting statistics, i.e. the number of charges in a given domain of space. For both these observables, the regime of typical fluctuations [1] and the large deviation regime [2, 3] have been characterized.
While one would naively expect a smooth matching between these regimes, as it is the case for example for observables of Hermitian random matrices, it is not the case here. We solve this puzzle by showing that for both cases, an intermediate regime" of fluctuations emerges and characterize it in detail [4, 5]. This regime is universal with respect to a large class of confining potential. We have also considered potentials that do not enter this class and shown that there are cases where an intermediate regime of fluctuation does not appear.

References
[1] T. Shirai, J. Stat. Phys. 123, 615 (2006).
[2] R. Allez, J. Touboul, G. Wainrib, J. Phys. A: Math. Theor. 47, 042001
(2014).
[3] F. D. Cunden, F. Mezzadri, P. Vivo, J. Stat. Phys. 164, 1062 (2016).
[4] B. Lacroix-A-Chez-Toine, A. Grabsch, S. N. Majumdar, G. Schehr, J. Stat.
Mech.: Theory Exp. 013203 (2018).

The implementation of an organic reaction on industrial scale requires not only the adjustment of scale, but not less importantly a different way of looking at it.
In addition to focusing on the reaction parameters, focusing on the process is essential.
This add the process-way-of-thinking to the scope of the industrial chemist.
In this talk a process-way-of-thinking will be presented via a case study containing:
1. New chemistry (to the best of our knowledge) for synthesis of organic compound containing sulfur.[1]
2. Implementation of this chemistry in a scalable manner.
3. Some industrial considerations required upon scale up.
4. Application of the above in a telescoping (domino) type process.
[1] PCT/US2018/060659