Talks

The eigenstate thermalization hypothesis (ETH) provides a sufficient condition for thermalization and equilibration from any initial states in isolated systems with a large number of degrees of freedom. One part of this statement is that for large systems, the diagonal matrix elements of typical observables in the Hamiltonian eigenstate basis, that is, the expectation values of the energy eigenstates, depend smoothly on the corresponding energy values. This statement is highly related to the fact that the variance of the energy eigenstate expectation values is small. Indeed, it is conjectured that this variance shows power-law decay with respect to the Hilbert space dimension.

On the other hand, in general relativity, it is expected that heavy objects undergo gravitational collapse. Additionally, it is known that gravitational systems with black holes exhibit maximally chaotic properties. By using the holographic principle, or specifically the AdS/CFT correspondence, these facts imp...

Introduction: Additive manufacturing or 3D printing are key methodologies to produce libraries of bone substitutes to test them to identify highly osteoconductive microarchitectures for bone defects or bone augmentation. Bone is a lightweight, high strength structure and resembles in its trabecular microarchitecture a gothic style. TPMS architectures are also lightweight and high strength. Therefore, we produced triply periodic minimal surface (TPMS) lightweight-based scaffolds based on three different algorithms and tested them in a cranial defect and a bone augmentation model in rabbits. 8 Methodology For the production of scaffolds, we applied the CeraFab 7500 from Lithoz, a lithography-based additive manufacturing machine and studied tri-calcium phosphate- based and hydroxyapatite-based scaffolds. As in vivo test model, we used a calvarial defect and a bone augmentation model in rabbits. Histomorphometry revealed that all generatively produced structures were well osseointegrated i...

We construct baby universe corrected bulk black hole/ white hole orthonormal basis labeled by the geodesic length of timeslice in two sided black hole. Our construction gives manifestly well defined probability distribution for length as well as transition probability to a white hole. We compute these probability distributions perturbatively, and find that late time TFD state spreads over all BH/WH basis states, i.e. Susskind's grey hole, already at the second order in perturbation. We also comment on the inherent ambiguity in our construction of our geometric basis.

I will first consider the geometry of the complex hyperbolic plane and immersed surfaces therein, in particular the cases of Lagrangian and complex surfaces. The complex surfaces are all minimal, but there are many others as well. As it is a symmetric space, the more general case of harmonic maps from a Riemann surface into the complex hyperbolic plane naturally generates holomorphic data of a Higgs bundle. We impose a compactness condition to relate our study of minimal surfaces to Higgs bundles. Let S be a closed Riemann surface of genus at least 2. Consider then harmonic immersions of the universal cover of S into the complex hyperbolic plane which are equivariant with respect to some representation of the fundamental group of S into the group P U(2, 1) of holomorphic isometries of the complex hyperbolic plane. In this case, the nonlinear Hodge correspondence applies and thus there is a (poly-)stable Higgs bundle over S. In the standard case of the group GL(n, C), this consists of a...

Outline of Topics:

Minimal Surfaces in Diblock Copolymers: the P,G, and D triply periodic minimal surfaces.
Smectic Liquid Crystals: the simplest crystals and they are built from surfaces.
Using minimal surfaces to knit: geometric scaffolds in materials science.

Introduction: In the last decades, advances in bone tissue engineering mainly based on osteoinduction and on stem cell research. Only recently, new efforts focused on the micro- and nanoarchitecture of bone substitutes to improve and accelerate bone regeneration. By the use of additive manufacturing, diverse microarchitectures were tested to identify the ideal pore size [1], the ideal filament distance and diameter [2], or light-weight microarchitecture [3], for osteoconduction to minimize the chance for the development of non-unions. Overall, the optimal microarchitecture doubled the efficiency of scaffold-based bone regeneration without the need for growth factors or cells. Another focus is on bone augmentation, a procedure mainly used in the dental field.

Methods: For the production of scaffolds, we applied the CeraFab 7500 from Lithoz, a lithographybased additive manufacturing machine. Hydroxyapatite-based and tri-calcium-phosphate-based scaffolds were produced with Lithoz TCP 3...