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Can a chatbot be a co-author? AI helps crack a long-stalled gluon amplitude proof

Like many scientists, theoretical physicist Andrew Strominger was unimpressed with early attempts at probing ChatGPT, receiving clever-sounding answers that didn’t stand up to scrutiny. So he was skeptical when a talented former graduate student paused a promising academic career to take a job with OpenAI. Strominger told him physics needed him more than Silicon Valley.

Still, Strominger, the Gwill E. York Professor of Physics, was intrigued enough by AI that he agreed when the former student, Alex Lupsasca, Ph.D., invited him to visit OpenAI last month to pose a thorny problem to the firm’s powerful in-house version of ChatGPT.

Strominger came away with much more than he expected—and the field of theoretical physics appears to have gained a little something too.

Twisting optical fiber creates a robust new pathway for light

Light powers everything from communications to sensing, yet even tiny imperfections can scatter it and weaken signals. To address this, a team led by the University of Bath—working with the University of Cambridge and international partners—has developed a new structure that keeps light flowing smoothly even through bends, twists or damage, with the potential to operate over unprecedented distances.

Quantum algorithm beats classical tools on complement sampling tasks

Quantum computers—devices that process information using quantum mechanical effects—have long been expected to outperform classical systems on certain tasks. Over the past few decades, researchers have worked to rigorously demonstrate such advantages, ideally in ways that are provable, verifiable and experimentally realizable.

A team of researchers working at Quantinuum in the United Kingdom and QuSoft in the Netherlands has now developed a quantum algorithm that solves a specific sampling task—known as complement sampling—dramatically more efficiently than any classical algorithm. Their paper, published in Physical Review Letters, establishes a provable and verifiable quantum advantage in sample complexity: the number of samples required to solve a problem.

“We stumbled upon the core result of this work by chance while working on a different project,” Harry Buhrman, co-author of the paper, told Phys.org. “We had a set of items and two quantum states: one formed from half of the items, the other formed from the remaining half. Even though the two states are fundamentally distinct, we showed that a quantum computer may find it hard to tell which one it is given. Surprisingly, however, we then realized that transforming one state into the other is always easy, because a simple operation can swap between them.”

Quantum computers go high-dimensional with a four-state photon gate

The collaboration of TU Wien with research groups in China has resulted in a crucial building block for a new kind of quantum computer: The realization of a novel type of quantum logic gate makes it possible to carry out quantum computations on pairs of photons that are each in four different quantum states, or combinations thereof. The advancement is an important milestone for optical quantum computers. The study has now been published in Nature Photonics.

The basic idea of quantum computers is simple: While a classical computer only works with the values “0” and “1,” quantum physics allows for arbitrary combinations of these states. In a certain sense, a quantum bit (“qubit”) can be in the states 0 and 1 simultaneously. This makes it possible to develop algorithms that can solve some problems much faster than a comparable classical computer.

However, such superpositions can in principle involve more than two states. Depending on what degree of freedom one considers, a quantum system such as a photon may not just have two different settings—two different outcomes of a potential measurement—but many. In this case, one refers to the system as a “qudit” rather than a “qubit.”

Ultra-efficient optical sensors can keep light circulating longer inside a microscopic chip

CU Boulder researchers have built high-performing optical microresonators, opening the door for new sensor technologies. At its simplest form, a microresonator is a tiny device that can trap light and build up its intensity. Once the intensity is high enough, researchers can perform unique light operations.

“Our work is about using less optical power with these resonators for future uses,” said Bright Lu, a fourth-year doctoral student in electrical and computer engineering and a lead author on the study. “One day these microresonators can be adapted for a wide range of sensors from navigation to identifying chemicals.”

For this endeavor, published in Applied Physics Letters, the team focused on “racetrack” resonators, named for their elongated shape that resembles a running track.

Sunray-like ripples emerge on a frozen reaction front

Researchers in Belgium have unveiled a striking chemical reaction in which ripples along a frozen reaction front resemble the rays of a shining star. Publishing their results in Physical Review Letters, Anne De Wit and colleagues at the Université Libre de Bruxelles have shed new light on the patterns that emerge in reaction–diffusion systems, offering fresh insight into how similar structures arise in the natural world.

From forest fires to the spread of infectious diseases, many natural processes involve a “front” forming between two distinct states: be they burned and unburned forest, infected and healthy individuals, or any number of other examples in which one state spreads by consuming another.

Such behavior is often described using reaction–diffusion systems, where local reactions are coupled to transport processes such as diffusion. In the lab, this mechanism can be recreated by injecting a chemical compound into the center of a circular chamber filled with another reactant. If the chemistry is autocatalytic —where one of the reaction products catalyzes its own formation—a circular reaction front will form around the injection point.

How to improve the performance of qubits: Super-fast fluctuation detection achieved

Using commercially available technology and innovative methods, researchers at NBI have pushed the limits of how fast you can detect changes in the sensitive quantum states in the qubit. Their work allows researchers to follow rapid changes in qubit performance that were previously invisible. The study is published in the journal Physical Review X.

The workhorse of any quantum-based application aimed at the coveted, but not yet fully realized quantum computer is the qubit. It is, however, a rather fragile workhorse.

Qubits, and quantum processors in general, are highly sensitive to their environment. Typically, the materials in which they are embedded contain microscopic defects that are still not fully understood. These defects can spatially fluctuate extremely fast, sometimes hundreds of times per second. As they fluctuate, the rate at which a qubit loses energy, and therefore useful quantum information, also changes.

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