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Google identifies low noise β€œphase transition” in its quantum processor

Back in 2019, Google made waves by claiming it had achieved what has been called "quantum supremacy"β€”the ability of a quantum computer to perform operations that would take a wildly impractical amount of time to simulate on standard computing hardware. That claim proved to be controversial, in that the operations were little more than a benchmark that involved getting the quantum computer to behave like a quantum computer; separately, improved ideas about how to perform the simulation on a supercomputer cut the time required down significantly.

But Google is back with a new exploration of the benchmark, described in a paper published in Nature on Wednesday. It uses the benchmark to identify what it calls a phase transition in the performance of its quantum processor and uses it to identify conditions where the processor can operate with low noise. Taking advantage of that, they again show that, even giving classical hardware every potential advantage, it would take a supercomputer a dozen years to simulate things.

Cross entropy benchmarking

The benchmark in question involves the performance of what are called quantum random circuits, which involves performing a set of operations on qubits and letting the state of the system evolve over time, so that the output depends heavily on the stochastic nature of measurement outcomes in quantum mechanics. Each qubit will have a probability of producing one of two results, but unless that probability is one, there's no way of knowing which of the results you'll actually get. As a result, the output of the operations will be a string of truly random bits.

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Protein structure and design software gets the Chemistry Nobel

On Wednesday, the Nobel Committee announced that it had awarded the Nobel Prize in chemistry to researchers who pioneered major breakthroughs in computational chemistry. These include two researchers at Google's DeepMind in acknowledgment of their role in developing AI software that could take a raw protein sequence and use it to predict the three-dimensional structure the protein would adopt in cells. Separately, the University of Washington's David Baker was honored for developing software that could design entirely new proteins with specific structures.

The award makes for a bit of a theme for this year, as yesterday's Physics prize honored AI developments. In that case, the connection to physics seemed a bit tenuous, but here, there should be little question that the developments solved major problems in biochemistry.

Understanding protein structure

DeepMind, represented by Demis Hassabis and John Jumper, had developed AIs that managed to master games as diverse as chess and StarCraft. But it was always working on more significant problems in parallel, and in 2020, it surprised many people by announcing that it had tackled one of the biggest computational challenges in existence: the prediction of protein structures.

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Β© Johan Jarnestad/The Royal Swedish Academy of Science

IBM opens its quantum-computing stack to third parties

As we described earlier this year, operating a quantum computer will require a significant investment in classical computing resources, given the amount of measurements and control operations that need to be executed and interpreted. That means that operating a quantum computer will also require a software stack to control and interpret the flow of information from the quantum side.

But software also gets involved well before anything gets executed. While it's possible to execute algorithms on quantum hardware by defining the full set of commands sent to the hardware, most users are going to want to focus on algorithm development, rather than the details of controlling any single piece of quantum hardware. "If everyone's got to get down and know what the noise is, [use] performance management tools, they've got to know how to compile a quantum circuit through hardware, you've got to become an expert in too much to be able to do the algorithm discovery," said IBM's Jay Gambetta. So, part of the software stack that companies are developing to control their quantum hardware includes software that converts abstract representations of quantum algorithms into the series of commands needed to execute them.

IBM's version of this software is called Qiskit (although it was made open source and has since been adopted by other companies). Recently, IBM made a couple of announcements regarding Qiskit, both benchmarking it in comparison to other software stacks and opening it up to third-party modules. We'll take a look at what software stacks do before getting into the details of what's new.

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We can now watch Grace Hopper’s famed 1982 lecture on YouTube

Rear Admiral Grace Hopper on Future Possibilities: Data, Hardware, Software, and People (Part One, 1982).

The late Rear Admiral Grace Hopper was a gifted mathematician and undisputed pioneer in computer programming, honored posthumously in 2016 with the Presidential Medal of Freedom. She was also very much in demand as a speaker in her later career. Hopper's famous 1982 lecture on "Future Possibilities: Data, Hardware, Software, and People," has long been publicly unavailable because of the obsolete media on which it was recorded. The National Archives and Records Administration (NARA) finally managed to retrieve the footage for the National Security Agency (NSA), which posted the lecture in two parts on YouTube (Part One embedded above, Part Two embedded below).

Hopper earned undergraduate degrees in math and physics from Vassar College and a PhD in math from Yale in 1930. She returned to Vassar as a professor, but when World War II broke out, she sought to enlist in the US Naval Reserve. She was initially denied on the basis of her age (34) and low weight-to-height ratio, and also because her expertise elsewhere made her particularly valuable to the war effort. Hopper got an exemption, and after graduating first in her class, she joined the Bureau of Ships Computation Project at Harvard University, where she served on the Mark I computer programming staff under Howard H. Aiken.

She stayed with the lab until 1949 and was next hired as a senior mathematician by Eckert-Mauchly Computer Corporation to develop the Universal Automatic Computer, or UNIVAC, the first computer. Hopper championed the development of a new programming language based on English words. "It's much easier for most people to write an English statement than it is to use symbols," she reasoned. "So I decided data processors ought to be able to write their programs in English and the computers would translate them into machine code."

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People game AIs via game theory

A judge's gavel near a pile of small change.

Enlarge / In the experiments, people had to judge what constituted a fair monetary offer. (credit: manusapon kasosod)

In many cases, AIs are trained on material that's either made or curated by humans. As a result, it can become a significant challenge to keep the AI from replicating the biases of those humans and the society they belong to. And the stakes are high, given we're using AIs to make medical and financial decisions.

But some researchers at Washington University in St. Louis have found an additional wrinkle in these challenges: The people doing the training may potentially change their behavior when they know it can influence the future choices made by an AI. And, in at least some cases, they carry the changed behaviors into situations that don't involve AI training.

Would you like to play a game?

The work involved getting volunteers to participate in a simple form of game theory. Testers gave two participants a pot of moneyβ€”$10, in this case. One of the two was then asked to offer some fraction of that money to the other, who could choose to accept or reject the offer. If the offer was rejected, nobody got any money.

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Lightening the load: AI helps exoskeleton work with different strides

Image of two people using powered exoskeletons to move heavy items around, as seen in the movie Aliens.

Enlarge / Right now, the software doesn't do arms, so don't go taking on any aliens with it. (credit: 20th Century Fox)

Exoskeletons today look like something straight out of sci-fi. But the reality is they are nowhere near as robust as their fictional counterparts. They’re quite wobbly, and it takes long hours of handcrafting software policies, which regulate how they workβ€”a process that has to be repeated for each individual user.

To bring the technology a bit closer to Avatar’s Skel Suits or Warhammer 40k power armor, a team at North Carolina University’s Lab of Biomechatronics and Intelligent Robotics used AI to build the first one-size-fits-all exoskeleton that supports walking, running, and stair-climbing. Critically, its software adapts itself to new users with no need for any user-specific adjustments. β€œYou just wear it and it works,” says Hao Su, an associate professor and co-author of the study.

Tailor-made robots

An exoskeleton is a robot you wear to aid your movementsβ€”it makes walking, running, and other activities less taxing, the same way an e-bike adds extra watts on top of those you generate yourself, making pedaling easier. β€œThe problem is, exoskeletons have a hard time understanding human intentions, whether you want to run or walk or climb stairs. It’s solved with locomotion recognition: systems that recognize human locomotion intentions,” says Su.

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Researchers describe how to tell if ChatGPT is confabulating

Researchers describe how to tell if ChatGPT is confabulating

Enlarge (credit: Aurich Lawson | Getty Images)

It's one of the world's worst-kept secrets that large language models give blatantly false answers to queries and do so with a confidence that's indistinguishable from when they get things right. There are a number of reasons for this. The AI could have been trained on misinformation; the answer could require some extrapolation from facts that the LLM isn't capable of; or some aspect of the LLM's training might have incentivized a falsehood.

But perhaps the simplest explanation is that an LLM doesn't recognize what constitutes a correct answer but is compelled to provide one. So it simply makes something up, a habit that has been termed confabulation.

Figuring out when an LLM is making something up would obviously have tremendous value, given how quickly people have started relying on them for everything from college essays to job applications. Now, researchers from the University of Oxford say they've found a relatively simple way to determine when LLMs appear to be confabulating that works with all popular models and across a broad range of subjects. And, in doing so, they develop evidence that most of the alternative facts LLMs provide are a product of confabulation.

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