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Light is all around us, essential for one of our primary senses (sight) as well as life on Earth itself. It underpins many technologies that affect our daily lives, including energy harvesting with solar cells, light-emitting-diode (LED) displays and telecommunications through fiber optic networks.

The smartphone is a great example of the power of light. Inside the box, its electronic functionality works because of quantum mechanics. The front screen is an entirely photonic device: liquid crystals controlling light. The back too: white light-emitting diodes for a flash, and lenses to capture images.

We use the word photonics, and sometimes optics, to capture the harnessing of light for and technologies. Their importance in is celebrated every year on 16 May with the International Day of Light.

Quantum entanglement—a connection between particles that produces correlations beyond what is classically possible—will be the backbone of future quantum technologies, including secure communication, cloud quantum computing, and distributed sensing. But entanglement is fragile; noise from the environment degrades entangled states over time, leaving scientists searching for methods to improve the fidelity of noisy entangled states.

Now, researchers at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME), University of Illinois Urbana-Champaign, and Microsoft have shown that it is fundamentally impossible to design a single one-size-fits-all protocol to counteract that noise.

“In , we often hope for a protocol that works in all scenarios—a kind of cure-all,” said Asst. Prof. Tian Zhong, senior author of the new work published in Physical Review Letters. “This result shows that when it comes to purifying entanglement, that’s simply too good to be true.”

To improve photonic and electronic circuitry used in semiconductor chips and fiber optic systems, researchers at the McKelvey School of Engineering at Washington University in St. Louis tinkered with the rules of physics that govern the movement of light over time and space. They have introduced a new way to manipulate light transmission, opening possibilities for advanced optical devices.

Their method causes a “mirror-flip of the system,” said Lan Yang, the Edwin H. & Florence G. Skinner Professor of electrical and and senior author of the research, now published in Science Advances.

Using parity-time (PT) symmetric photonic waveguides, they can manipulate the light waves to “reverse time” so the system behaves the same as before, Yang added.

As demand surges for batteries that store more energy and last longer—powering electric vehicles, drones, and energy storage systems—a team of South Korean researchers has introduced an approach to overcome a major limitation of conventional lithium-ion batteries (LIBs): unstable interfaces between electrodes and electrolytes.

Most of today’s consumer electronics—such as smartphones and laptops—rely on graphite-based batteries. While graphite offers long-term stability, it falls short in .

Silicon, by contrast, can store nearly 10 times more lithium ions, making it a promising next-generation anode material. However, silicon’s main drawback is its dramatic volume expansion and contraction during charge and discharge, swelling up to three times its original size.

While some quantum computing companies push to demonstrate near-term commercial value, Rigetti Computing is taking a different approach. The company has identified specific technical milestones it said must be achieved before quantum systems can deliver meaningful business results, including 99.9% fidelity, 20-nanosecond gate speeds and real-time error correction.

In an interview we conducted at The Economist Commercializing Quantum event, Rigetti CEO Subodh Kulkarni outlined how the company’s novel chiplet-based architecture could help scale systems to 10,000 qubits, while also revealing an intriguing potential role for quantum computing in advancing artificial general intelligence.

Enter Quantum: What’s your take on the debate between return on investment versus technical capability in quantum computing?

A scientist from Tokyo Metropolitan University has solved the longstanding problem of a “dissonance” in gravitational waves emitted by a black hole.

Using high precision computing and a new theoretical physics framework, it was discovered that it was caused by a resonance between a pair of distinctive “modes” i.e. different ways in which a black hole can “ring.” The phenomenon offers new insights into the nascent field of black hole spectroscopy.

The research is published in the journal Physical Review Letters.

Anyone who speculates on likely events ahead of time and prepares accordingly can react quicker to new developments. What practically every person does every day, consciously or unconsciously, is also used by modern computer processors to speed up the execution of programs. They have so-called speculative technologies which allow them to execute instructions on reserve that experience suggests are likely to come next. Anticipating individual computing steps accelerates the overall processing of information.

However, what boosts computer performance in normal operation can also open up a backdoor for hackers, as recent research by computer scientists from the Computer Security Group (COMSEC) at the Department of Information Technology and Electrical Engineering at ETH Zurich shows.

The computer scientists have discovered a new class of vulnerabilities that can be exploited to misuse the prediction calculations of the CPU (central processing unit) in order to gain unauthorized access to information from other processor users. They will present their paper at the 34th USENIX Security Symposium (USENIX 2025), to be held August 13–15, 2025, in Seattle.

As more data is archived digitally, the inherent fragility of bits remains a pressing issue. The answer may lie in ceramics. Western Digital has invested in Cerabyte, a company developing a groundbreaking storage technology designed to preserve data reliably for millennia.

Cerabyte’s technology stores digital data on ceramic nanolayers, using lasers to etch QR code-like matrices representing bits. Ceramics, known for their resistance to corrosion and extreme heat, have endured for millennia. The German startup claims its storage method could preserve digital data for over 5,000 years.

Cerabyte recently demonstrated its technology’s durability by heating a prototype storage medium to 250°C in an oven. Both the medium and the archived data emerged unscathed. The company stated its ceramic-based solution could meet the rising demand for long-term data storage platforms.