Integrated Calendar

Nuclear magnetic resonance (NMR) spectroscopy is a versatile tool for probing structure, dynamics, folding, and interactions at atomic resolution. While naturally occurring magnetically active isotopes, such as 1H, 13C, or 15N, are most commonly used in biomolecular NMR, with 15N and 13C isotopic labeling routinely employed at the present time, 19F is a very attractive and sensitive alternative nucleus, which offers rich information on biomolecules in solution and in the solid state. This presentation will summarize the unique benefits of solution and solid-state 19F NMR spectroscopy for the study of biomolecular systems. Particular focus will be placed on the most recent studies and on unique and important potential applications of fluorine NMR methodology.

I will describe the photonic approach to quantum computation, which is the only technology that has been originally designed to reach the massive scaling required for fault- tolerant universal computation (> 106 physical qubits). It combines topological error correction and measurement-based quantum computation, with the leading effort relying on massive-scale silicon photonics.
I will then describe how cavity-QED with single atoms allows deterministic photon-atom two qubit gates, which in turn can drastically simplify the road towards fault-tolerant photonic quantum computing and improve its scaling to even larger numbers of physical qubits.

Molecular crystals are supramolecules “par excellence"1 as they are macroscopic objects composed by millions of molecules periodically disposed and held together by non-covalent interactions with specific physico-chemical properties dictated by their architectures. This offers a vibrant solid-state chemistry playground to build organic solids with tailored functionalities, such as novel luminescent materials,2 solid-state molecular machines,3 and multicomponent crystals with complex topologies.4 The inherent dynamic nature of the weak intermolecular forces that are driving organic crystals self-assembly is also conferring adaptive responsiveness, e.g., mechanical reconfiguration and shape-memory effect, to this class of materials making them ideal building blocks for the design and synthesis of multifunctional crystalline systems that can be exploited as actuators, flexible single-crystalline optoelectronic devices, and self-healing materials.5

When we fall asleep, brain function and physiology are rapidly transformed. Understanding the neural basis of sleep requires imaging methods that can capture multiple aspects of brain physiology at fast timescales. We develop approaches for analyzing human brain physiology using multimodal neuroimaging, and apply them to investigate the neural origins and consequences of sleep. We found that accelerated methods for fMRI can enable imaging subsecond neural dynamics throughout the human brain. We applied these methods to investigate the neural dynamics that occur at state transitions, and identified temporal sequences within thalamocortical networks that precede the moment of awakening from sleep. In addition, we developed a method to image cerebrospinal fluid flow, and discovered large waves of fluid flow that appear in the sleeping human brain. Together, these studies highlight the new biological information that can be extracted from fast fMRI data, and use this approach to discover neurophysiological dynamics unique to the sleeping brain.
Link: https://weizmann.zoom.us/j/95406893197?pwd=REt5L1g3SmprMUhrK3dpUDJVeHlrZz09
Meeting ID: 954 0689 3197
Password: 750421

X-ray precision polarimetry and the detection of vacuum birefringence

Vacuum isn’t just empty space. Rather there is a continuous creation and annihilation of virtual pairs. A strong electric field can align them to a certain degree such that vacuum becomes birefringent – according to quantum electrodynamics. The effect has been predicted almost 90 years ago, but never been directly verified to date.

We have been developing X-ray polarimetry over the past 12 years in order to detect vacuum birefringence. The current status is an extinction ratio of 11 orders of magnitude using channel-cut crystals. This is a figure not nearly matched by any other polarimeter in any spectral region. Besides the physics of X-ray polarimetry, I will also discuss the remaining issues for the detection of vacuum birefringence.


The Helium hydride ion in strong laser fields

The Helium hydride ion is considered to be the first molecule that has formed after the big bang, a fact already pointing to the fundamental importance of this ion. Nevertheless, its behavior in intense, ultrashort laser fields has not been addressed until recently. This is in strong contrast to another fundamentally important molecule, the hydrogen molecular ion, on which many thousands of papers have been published.

I will discuss a series of experiments using different isotopologues of the Helium hydride ion at different wavelengths. The dissociation and ionization dynamics turns out to be vastly different from the hydrogen molecular ion. Moreover, it changes dramatically when moving from the near- to the mid-infrared spectral region. Although Helium hydride and the hydrogen molecule are isoelectronic, they can be seen as opposing extremes.