Seminars

Creating, manipulating, and detecting coherent, entangled quantum states and isolating quantum systems from decoherence are at the heart of future quantum information science technologies. In this talk the new QUINTESSENCE project at the Molecular Foundry is presented. We aim to set up a quantum information instrument that opens the door for novel techniques that combine electron microscopy, surface analysis, and matter-wave interferometry. We will develop the first spin-polarized low-energy electron microscope with a helium temperature sample stage. We will construct a matter-wave interferometer with an electron biprism to directly map decoherence processes resulting from long-distance charge-surface interactions. Finally, we will develop a superconducting field-emission electron source with an ultra-low energy spread and therefore greatly increased coherence. This source has the potential to produce entangled free electron pairs with opposed spin and initial momentum, enabling research in quantum information science, Einstein–Podolsky–Rosen physics, as well as new modes of low-energy electron microscopy and decoherence mapping.
The talk will describe the current status of these experiments and present decoherence measurements in an electron biprism interferometer. Recent results also demonstrate that such a device can be used for signal transmission by a nontrivial quantum matter wave modulation that does not shift the transverse phase or position of the electron beam. This was achieved by using a Wien Filter to switch the fringe contrast between maximum and minimum. The origin of this binary encoding is a longitudinal shift between the separated matter wave packets that is longer than the longitudinal coherence length. The information is read out by a dynamic contrast analysis in a delay line detector.

Dr. Alexander Stibor studied Physics in Austria (Graz, Vienna) and in The Netherlands (Groningen). He finished his Doctorate thesis with the title: Optical Methods for Macromolecule Interferometry in 2005 at the University of Vienna, Austria, in the group of Prof. Arndt and Prof. Zeilinger. Then he moved to the University of Tübingen, Germany, to work as a postdoc (Marie Curie ER Fellowship) in the groups of Prof. Zimmermann and Prof. Fortágh on detection methods for ultracold quantum gases in magnetic microchip traps. In 2010, Dr. Stibor got the Emmy Noether Research Grant from the German Research Association (DFG) which allowed him to establish his own group Quantum Electron and Ion Interferometry at the University of Tübingen. The research focus is on matter wave experiments with electrons and ions including decoherence measurements, sensor technology and the development of novel coherent beam sources. In 2016, Dr. Stibor got the opportunity to be a Visiting Scholar at Stanford University, USA, in the Atom Science group of Prof. Kasevich to create novel laser pulsed nanotip electron beam sources for quantum microscopy. Since April 2018, he has held a Physicist Project Scientist position at Berkeley Lab at the Molecular Foundry. Dr. Stibor and his colleagues (Dr. Schmid, Dr. Ogletree, and others) wrote the project proposalQUINTESSENCE which was recently funded by the DOI in the framework of the QIS initiative. Thereby, novel superconducting entangled electron beam sources and surface probing techniques by decoherence analysis are developed in connection with a new cryo-stage cooled low energy electron microscope.

As evidenced by numerous experimental and theoretical studies, application of high pressure can dramatically modify the atomic arrangement and electronic structures of both elements and compounds. However, the great majority of research has been focused on the effect of pressure on compounds with constant stoichiometries (typically those stable under ambient conditions). Recent experimental studies and theoretical predictions, using advanced search algorithms, suggest that the more stable stoichiometry at elevated pressures, and thus the chemical properties of elements, is not a priory the same as that at ambient pressure. Indeed, thermodynamically stable compounds with novel compositions were theoretically predicted and experimentally verified even in relatively simple chemical systems including: Na-Cl, C-N, Na-H Cs-N, H-N, Na-He, Xe-Fe, Ar-Ni. These materials are stable due to the formation of novel chemical bonds that are absent, or even forbidden, at ambient conditions.

By varying the stoichiometry one can design novel materials with enhanced properties (e.g. high energy density, hardness, superconductivity etc.), that are metastable at ambient conditions and synthesized at thermodynamic conditions less extreme than those required for known stoichiometries. Moreover, current outstanding questions, in geo- and planetary science (e.g. the xenon paradox) could be addressed based on the stability of surprising stoichiometries that challenge our traditional “textbook” picture. In this talk, I will present recent results and highlight the need of close synergy between experimental and theoretical efforts to understand the novel chemical properties of elements under high-pressure conditions in the challenging and complex field of variable stoichiometry under pressure. Finally, possible new routes for the synthesis of novel materials will be discussed.

This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

Dr. Elissaios Stavrou received his Ph.D. from the National Technical University of Athens, Greece. Currently he is a staff scientist in the Materials Science Division at Lawrence Livermore National Laboratory. Prior to joining LLNL in 2014, he worked as a postdoc on high-pressure phase transitions, lattice dynamics, and synthesis of novel compounds at the Max Planck Institute for solid state research and at the Geophysical Laboratory/Carnegie institution of Washington. His main research interests focus on the equation of state of energetic materials and the synthesis of novel compounds under extreme thermodynamic conditions.

Fluctuations, Brownian motion or thermal noise is where materials store thermal energy. Fluctuations are what keeps materials in equilibrium or allows them to change in response to external changing conditions. X-ray photon correlation spectroscopy (XPCS) is a technique that uses the coherence properties of x-rays to give detailed information about structural fluctuations and their dynamics at nanometer length scales, both in equilibrium and non-equilibrium systems. After discussing the basis of the technique, this talk will discuss three aspects of XPCS. First, some of the interesting results obtained to date; second, the current status and limitations of XPCS; and finally, the exciting new capabilities opened up by new sources such as the APS Upgrade and x-ray free-electron lasers.

Mark Sutton is a Professor Emeritus at McGill University. He has more than 35 years of experience using synchrotrons. He has been involved with the design and construction of Beamline X20 at the National Synchrotron Light Source and Sector 8 at the Advanced Photon Source. His studies concentrate on equilibrium and non-equilibrium dynamics of systems of interest to materials science. Most recently, he has been employing the ability to perform x-ray photon correlation spectroscopy using coherent x-ray beams. This technique exploits the unique properties of the coherent radiation from undulators at third-generation synchrotron sources, as well as recent developments in x-ray optics and detector technology. He is a fellow of the Royal Society of Canada and a member of the Canadian Association of Physics. He has been awarded the Compton Medal from the Advanced Photon Source and the Brockhouse Medal and the Medal for Lifetime Achievement in Physics from the Canadian Association of Physicists.

Cataracts, named for the lens opacity, remain the leading cause of human blindness in the world. The lens, mainly consisting of a bulk of elongated fibers, is like a liquid crystal to provide a focused imaging of our vision. However, the principle and maintenance of lens transparency throughout our life remain poorly understood. Cataract risk factors include aging, predisposed genetic factors, and radiation damage. I will talk about how lens transparency and cataractogenesis are influenced by lens architecture, fiber cell morphogenesis, and metabolism, and will discuss the molecular and cellular regulations of lens elongating fibers and different genetic variances of cytoskeleton and cell junctions that coordinately control lens development and transparency. I will also share a recent achievement of the generation of a bio-artificial lens by using a novel lensgineering technology in discovering new reagents in vitro for controlling lens formation. Finally, I will address the challenges for understanding the principles of lens transparency and optic properties and for developing nonsurgical approaches to suppress the cataract formation.

Dr. Xiaohua Gong is currently a full professor of Optometry and Vision Science, Stem Cell Center, UC Berkeley-UCSF. He performed his graduate studies in Bioengineering in UC Berkeley, USA. He is also an affiliated professor at Tsinghua Berkeley Shenzhen Institute, China. He received a BA from the school of pharmacy, Fudan University and MS from the department of biochemistry and molecular genetics at Shanghai Medical School, Fudan University, China; and PhD from the department of cell biology at The Scripps Research Institute, and a Postdoctoral fellowship in School of Medicine at UC San Diego, USA.

Dr. Gong’s research aims to study molecular and cellular mechanisms of eye development and diseases, especially cataracts and retinal degenerations, by using multidisciplinary techniques from the fields of genetics, molecular and cellular biology, biochemistry, and physiology. Dr. Gong has been granted five NIH research grants since 2000 and one East Bay Community Foundation grant and a NIH/NEI core grant for vision research. He has more than 60 publications in peer-reviewed journals.

Dr. Gong is a permanent member of the NIH Peer Review Committee—BVS study section, a permanent member of the Biology & Medicine Panel of the Research Grant Council of Hong Kong, and an editorial board member for JBC, served as a reviewer for many academic journals including PNAS, Development, JBC, J of Cell Science, Investigative Ophthalmology & Visual Science (IOVS), Experimental Eye Research, Mechanisms of Development, etc. He is a member of the Association for Research in Vision and Ophthalmology, a member of the American Society for Cell Biology. At UC Berkeley, Dr. Gong is a member of the graduate advisory committee in the Vision Science program, a member of thesis committee of Ph.D. candidates, a member of qualifying exam committee of Ph.D. graduate students, and a member of the admission committee for the UCSF/UCB Bioengineering graduate program.

Computing is at a momentous point, as devices approach the 10-nm dimension even as new breakthrough AI/QC architectures evolve. In this talk, I will outline the framework that combines energy/dimension scaling (Moore’s law), computer error rates (Shannon computing), and modern AI architectures. I also outline how the next room-temperature computing device can be made from quantum materials exploiting the correlated electron phenomenon.

We describe a quantum materials-centric approach to enable the compute device layer for beyond the CMOS era. I will outline a number of pathways for computing devices that utilize quantum materials. In particular, I will describe the concept device (named Magneto-electric Spin Orbit Logic) used by Intel to drive high functionality materials in magneto-electrics and topological materials. In particular, the path to computing at aJ/bit (~30X more energy efficient than advanced CMOS) with 10-20X relaxation of the interconnect requirements will be described.

In the second half, I will describe the connection between AI computing and memory, identifying the key bottlenecks for reaching 1000 TOPS/W (a 100X leap over today’s GPUs/ASICs). Quantum materials, especially next-generation ferro-electrics and magnetics, can mitigate this memory wall. I will also describe the experimental methods to scale switching voltages to 100 mV (5X below advanced CMOS) using logic and SOTMRAM. Finally, a systems approach to modern computing comprehending spin/quantum circuit (the first industrially used Spin SPICE to design spin/quantum logic devices) and stochasticity that allows a holistic compute scaling will be described.

Sasikanth Manipatruni is working on building the next room-temperature transistor with quantum materials. He was the founding research director of Intel-FEINMAN center (Functional Electronics Integration and Manufacturing) and also senior counsel to the CTO of the Intel AI group. He received his PhD from Cornell, working with Prof. Michal Lipson in silicon photonics where he demonstrated ultra-fast silicon electro-optic switches, opto-mechanical non-reciprocity, and synchronization of opto-mechnical systems. At Intel, he developed materials and devices for beyond-CMOS memory/logic and built the first industrially adopted spintronic/quantum SPICE tool. He was awarded the IEEE/ACM Under-40 Innovators Award at DAC 2017, 2016 Mahboob Khan Outstanding Liaison Award, 2016 C-SPIN Outstanding Industry Liaison, and serves on several industry panels for research selection. His work is cited ~3600 times, and he holds ~200 granted/applied patents in spin/photonics/MEMS/CAD/AI/QC. He coaches middle and high school students for USA-PHO physics Olympiads.