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Professor Dorsa Sadigh joins Professor Russ Altman for a recent The Future of Everything podcast, titled "How do you build a better robot? By understanding people."
Whether it's autonomous vehicles or assistive technology in healthcare that can do things like help the elderly do core tasks like feeding themselves, some of the most challenging problems in the field of robotics involve how robots interact with humans, with all of our many complexities.
Drawing from fields as varied as cognitive neuroscience, psychology, and behavioral economics, Stanford computer scientist Dorsa Sadigh is exploring how to train robots to better understand humans – and how to give humans the skills to more seamlessly work with robots.
Learn more on this episode of Stanford Engineering's The Future of Everything, with host Professor Russ Altman. Listen and subscribe here.
Dan is a featured faculty on EE's "Meet our Faculty!" YouTube playlist. During the next few weeks, more videos about Dan and his research will post. Subscribe to receive notifications about new videos. Watch videos: Meet Assistant Professor Dan Congreve and learn about nanomaterial research in his lab.
Co-lead authors Koosha Nassiri Nazif and Alwin Daus, both EE postdoctoral scholars, describe their tungsten diselenide solar cells that boast a power-per-weight ratio on par with established thin-film solar cell technologies in their recently published paper. Their prototype achieves 5.1 percent power conversion efficiency, and the team projects they could practically reach 27 percent efficiency upon optical and electrical optimizations. That figure would be on par with the best solar panels on the market today, silicon included.
Their prototype realized a 100-times greater power-to-weight ratio of any transition metal dichalcogenides (TMDs) yet developed. That ratio is important for mobile applications, like drones, electric vehicles and the ability to charge expeditionary equipment on the move. When looking at the specific power – a measure of electrical power output per unit weight of the solar cell – the prototype produced 4.4 watts per gram, a figure competitive with other current-day thin-film solar cells, including other experimental prototypes.
Pictured below are Professor Krishna Saraswat (left) and Dr. Koosha Nassiri Nazif (right), and a photograph of WSe2 solar cells on a flexible polyimide substrate held up with a pair of tweezers. Photo credit: Dr. Koosha Nassiri Nazif.
Excerpted from "Stanford engineers and physicists study quantum characteristics of 'combs' of light"
Professor & Chair Jelena Vučković states, "Many groups have demonstrated on-chip frequency combs in a variety of materials, including recently in silicon carbide by our team. However, until now, the quantum optical properties of frequency combs have been elusive. We wanted to leverage the quantum optics background of our group to study the quantum properties of the soliton microcomb."
While soliton microcombs have been made in other labs, the Stanford researchers are among the first to investigate the system's quantum optical properties, using a process that they outline in a paper published Dec. 16 in Nature Photonics. When created in pairs, microcomb solitons are thought to exhibit entanglement – a relationship between particles that allows them to influence each other even at incredible distances, which underpins our understanding of quantum physics and is the basis of all proposed quantum technologies. Most of the "classical" light we encounter on a daily basis does not exhibit entanglement.
"This is one of the first demonstrations that this miniaturized frequency comb can generate interesting quantum light – non-classical light – on a chip," said Kiyoul Yang, a research scientist in Vučković's Nanoscale and Quantum Photonics Lab and co-author of the paper. "That can open a new pathway toward broader explorations of quantum light using the frequency comb and photonic integrated circuits for large-scale experiments."
Proving the utility of their tool, the researchers also provided convincing evidence of quantum entanglement within the soliton microcomb, which has been theorized and assumed but has yet to be proven by any existing studies.
"I would really like to see solitons become useful for quantum computing because it's a highly studied system," said Melissa Guidry, a graduate student in the Nanoscale and Quantum Photonics Lab and co-author of the paper. "We have a lot of technology at this point for generating solitons on chips at low power, so it would be exciting to be able to take that and show that you have entanglement."
Read full article: Stanford News, "Stanford engineers and physicists study quantum characteristics of 'combs' of light"
Today's quantum computers are complicated to build, difficult to scale up, and require temperatures colder than interstellar space to operate. These challenges have led researchers to explore the possibility of building quantum computers that work using photons — particles of light. Photons can easily carry information from one place to another, and photonic quantum computers can operate at room temperature, so this approach is promising. However, although people have successfully created individual quantum "logic gates" for photons, it's challenging to construct large numbers of gates and connect them in a reliable fashion to perform complex calculations.
Professor Shanhui Fan and Ben Bartlett (PhD candidate, Applied Physics) have proposed a design that uses a laser to manipulate a single atom that, in turn, can modify the state of the photons via a phenomenon called "quantum teleportation." The atom can be reset and reused for many quantum gates, eliminating the need to build multiple distinct physical gates, vastly reducing the complexity of building a quantum computer. Their paper on the proposed design has been published in Optica.
The scientists' design consists of two main sections: a storage ring and a scattering unit. The storage ring, which functions similarly to memory in a regular computer, is a fiber optic loop holding multiple photons that travel around the ring. Analogous to bits that store information in a classical computer, in this system, each photon represents a quantum bit, or "qubit." The photon's direction of travel around the storage ring determines the value of the qubit, which like a bit, can be 0 or 1. Additionally, because photons can simultaneously exist in two states at once, an individual photon can flow in both directions at once, which represents a value that is a combination of 0 and 1 at the same time.
The researchers can manipulate a photon by directing it from the storage ring into the scattering unit, where it travels to a cavity containing a single atom. The photon then interacts with the atom, causing the two to become "entangled," a quantum phenomenon whereby two particles can influence one another even across great distances. Then, the photon returns to the storage ring, and a laser alters the state of the atom. Because the atom and the photon are entangled, manipulating the atom also influences the state of its paired photon.
Excerpted from: "Stanford engineers propose a simpler design for quantum computers"
Professor Chelsea Finn joins Professor Russ Altman for a recent The Future of Everything podcast, titled "How to make artificial intelligence more meta."
In one of computer science's more meta moments, professor Chelsea Finn created an AI algorithm to evaluate the coding projects of her students. The AI model reads and analyzes code, spots flaws and gives feedback to the students. Computers learning about learning—it's so meta that Chelsea calls it "meta learning."
Chelsea says the field should forgo training AI for highly specific tasks in favor of training it to look at a diversity of problems to divine the common structure among those problems. The result is AI able to see a problem it has not encountered before and call upon all that previous experience to solve it. This new-look AI can adapt to new courses, often enrolling thousands of students at a time, where individual instructor feedback would be prohibitive.
Emboldened by results in class, she is now applying her breadth-over-specificity approach to her other area of focus, robotics. Chelsea hopes to develop new-age robots that can adapt to unfamiliar surroundings and can do many things well, instead of a few, as she tells host Russ Altman and listeners to this episode of Stanford Engineering's The Future of Everything podcast. Listen and subscribe here
Professor Gordon Wetzstein and his colleagues are working to come up with solutions to bridge a gap between simulation and reality while creating displays that are more visually appealing and easier on the eyes.
The research published in Science Advances details a technique for reducing a speckling distortion often seen in regular laser-based holographic displays, while the SIGGRAPH Asia paper proposes a technique to more realistically represent the physics that would apply to the 3D scene if it existed in the real world.
Excerpted from "Stanford researchers are using artificial intelligence to create better virtual reality experiences," November 12, 2021.
Founded in 2018, CBR's primary mission is to support the thriving blockchain ecosystem by developing new technologies needed to advance the field by bringing together engineering, law, and economics faculty, as well as post-docs, students, and visitors, to work on technical challenges in the field.
CBR has built an extensive education and outreach program, including on-campus courses, student groups (Blockchain Club and Blockchain Collective), MOOCs, workshops, and conferences for the general blockchain community.
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