Dramatic progress has been made in the last decade and a half towards realizing solid-state systems for quantum information processing with superconducting quantum circuits. Artificial atoms (or qubits) based on Josephson junctions have improved their coherence times more than a million-fold, have been entangled, and used to perform simple quantum algorithms. The next challenge for the field is demonstrating quantum error correction that actually improves the lifetimes, a necessary step for building more complex systems.
Here we demonstrate a fully operational quantum error correction system, based on a logical encoding comprised of superpositions of cat states in a superconducting cavity. This system uses real-time classical feedback to encode, track the naturally occurring errors, decode, and correct, all without the need for post-selection. Using this approach we reach, for the first time, the break-even point for QEC and preserve quantum information through active means.
Moreover, the performance of the system matches with predictions, and can be dramatically improved by making the protocol more fault tolerant. Mastering the practice of error correction, and understanding the overhead and complexity required, are the main scientific challenges remaining for reaching scalable quantum computation with this technology.
Robert Schoelkopf is the Sterling Professor of Applied Physics and Physics at Yale University. His research focuses on the development of superconducting devices for quantum information processing, which will lead to revolutionary advances in computing.
Over 300 years ago, an English carpenter realized that the key to safely navigating the ocean was being able to precisely measure time. Since then, timing and localization technologies have continued to push the limits of technology resulting in systems like GPS and our most sophisticated scientific instruments. Our new challenge in localization is providing coverage for indoor spaces where barriers attenuate and scatter radio signals. Precise indoor localization has the potential to enable applications ranging from asset tracking, indoor navigation and augmented reality all the way to highly optimized beam forming for improved spatial capacity of wireless networks.
In this talk, I will describe a localization system that uses time synchronized beacons with a combination of Bluetooth Low-Energy (BLE) and ultrasonic signals that are able to provide decimeter-ranging accuracy. The ultrasonic transmissions are designed to be inaudible to humans, but still detectable by microphones found on standard mobile devices. We are able to further improve localization performance by fusing information from the phone’s IMU as well as constraints derived from building floor plans. As these systems scale, we show how pedestrian range-based Simultaneous Localization and Mapping (SLAM) can be used to bootstrap the beaconing infrastructure as well as detect and correct configuration faults.
Anthony Rowe is an Associate Professor in the Electrical and Computer Engineering Department at Carnegie Mellon University. His research interests are in networked real-time embedded systems with a focus on wireless communication. His most recent projects have related to large-scale... read more »
As computing becomes increasingly pervasive in our daily life, it is generally recognized that energy efficiency will be one of the key design considerations for any future computing scheme. Consequently, significant research is currently ongoing on exploring new physics, material systems and system level designs to improve energy efficiency. In this talk, I shall discuss some of our recent progresses in this regard. Specifically, the physics of ordered and correlated systems allow for fundamental improvement of the energy efficiency when a transition happens between two distinguishable states. Our recent experiments show that this theoretical promise can indeed be realized in transistors and spintronic memory devices. The resulting gain in energy efficiency can easily exceed orders of magnitude.
Sayeef Salahuddin is an associate professor of Electrical Engineering and Computer Sciences at the University of California, Berkeley. His research interests are in the transport physics of nano structures currently focusing on novel electronic and spintronic devices for low power logic... read more »