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2025 Nobel Prize in Physics Peer Review

Introduction.

Grounded in the scientific method, it critically examines the work’s methodology, empirical validity, broader implications, and opportunities for advancement, aiming to foster deeper understanding and iterative progress in quantum technologies. ## Executive Summary.

This work, based on experiments conducted in 1984–1985, addresses a fundamental question in quantum physics: the scale at which quantum effects persist in macroscopic systems.

By engineering a Josephson junction-based circuit where billions of Cooper pairs behave collectively as a single quantum entity, the laureates provided empirical evidence that quantum phenomena like tunneling through energy barriers and discrete energy levels can manifest in human-scale devices.

This breakthrough bridges microscopic quantum mechanics with macroscopic engineering, laying foundational groundwork for advancements in quantum technologies such as quantum computing, cryptography, and sensors.

Overall strengths include rigorous experimental validation and profound implications for quantum information science, though gaps exist in scalability to room-temperature applications and full mitigation of environmental decoherence.

Framed within the broader context, this award highlights the enduring evolution of quantum mechanics from theoretical curiosity to practical innovation, building on prior Nobel-recognized discoveries like the Josephson effect (1973) and superconductivity mechanisms (1972).

Nobel Prize in Physics 2025

A major question in physics is the maximum size of a system that can demonstrate quantum mechanical effects. This year’s Nobel Prize laureates conducted experiments with an electrical circuit in which they demonstrated both quantum mechanical tunnelling and quantised energy levels in a system big enough to be held in the hand.

Quantum mechanics allows a particle to move straight through a barrier, using a process called tunnelling. As soon as large numbers of particles are involved, quantum mechanical effects usually become insignificant. The laureates’ experiments demonstrated that quantum mechanical properties can be made concrete on a macroscopic scale.

In 1984 and 1985, John Clarke, Michel H. Devoret and John M. Martinis conducted a series of experiments with an electronic circuit built of superconductors, components that can conduct a current with no electrical resistance. In the circuit, the superconducting components were separated by a thin layer of non-conductive material, a setup known as a Josephson junction. By refining and measuring all the various properties of their circuit, they were able to control and explore the phenomena that arose when they passed a current through it. Together, the charged particles moving through the superconductor comprised a system that behaved as if they were a single particle that filled the entire circuit.

Rethinking Our Place in the Universe

The new map of the Universe’s expansion history released by the DESI Collaboration offers hints at a breakdown of the standard model of cosmology.

For nearly a century, we have known that our Universe is expanding. For the past quarter-century, we have also known that this expansion is accelerating, a discovery that earned the 2011 Nobel Prize in Physics [1, 2]. But what is the mysterious “dark energy” that drives this acceleration? The simplest explanation involves what Einstein dubbed a “cosmological constant” (Λ) and implies that dark energy is a constant energy inherent to spacetime itself. This idea is the cornerstone of the standard model of cosmology, the Λ cold dark matter (ΛCDM) model, which for decades has consistently explained all available astronomical observations. Now high-precision measurements of the Universe’s expansion history are putting this model to its most stringent test yet. The Dark Energy Spectroscopic Instrument (DESI) has created a cosmic map of unprecedented scale (Fig. 1) [3–9].

Strontium optical lattice clock exhibits record-high coherence time

Optical lattice clocks are emerging timekeeping devices based on tens of thousands of ultracold atoms trapped in an optical lattice (i.e., a grid of laser light). By oscillating between two distinct quantum states at a particular frequency, these atoms could help to measure time with much higher precision than existing clocks, which would be highly advantageous for the study of various fundamental physical processes and systems.

Researchers at JILA, National Institute of Standards and Technology and University of Chicago recently developed an clock based on strontium atoms that was keeping time with remarkable precision and accuracy. The new strontium , introduced in a paper published in Physical Review Letters, could open new possibilities for research aimed at testing variations in fundamental physics constants and the timing of specific physical phenomena.

“We have been pushing the performance of the optical lattice clock,” Kyungtae Kim, first author of the paper, told Phys.org. “Thanks to a major upgrade from 2019 to 2021, we demonstrated record differential frequency measurement capability, reaching a resolution of gravitational redshift below the 1-mm scale, as well as record accuracy (until this July) as a frequency standard. To push the performance further, one needs to understand and model the current system. This work provides a detailed snapshot of the clock’s current operation.”

Researchers integrate waveguide physics into metasurfaces for advanced light control

Ultrathin structures that can bend, focus, or filter light, metasurfaces are reshaping how scientists think about optics. These engineered materials offer precise control over lights behavior, but many conventional designs are held back by inefficiencies. Typically, they rely on local resonances within individual nanostructures, which often leak energy or perform poorly at wide angles. These shortcomings limit their usefulness in areas like sensing, nonlinear optics, and quantum technologies.

A growing area of research looks instead to nonlocal metasurfaces, where interactions between many elements create collective optical effects. These collective behaviors can trap light more efficiently, producing sharper resonances and stronger interactions with matter. One of the most promising possibilities in this field is the development of photonic flatbands, where resonant behavior stays uniform across a wide range of viewing angles.

Another is creating chiral responses, which allow devices to distinguish between left-and right-handed circularly polarized light. Until now, however, achieving both flatband and chiral behavior with high efficiency on a single platform has remained a major challenge.

Quantum uncertainty captured in real time using femtosecond light pulses

Researchers from the University of Arizona, working with an international team, have captured and controlled quantum uncertainty in real time using ultrafast pulses of light. Their discovery, published in the journal Light: Science & Applications, could lead to more secure communication and the development of ultrafast quantum optics.

At the heart of the breakthrough is “squeezed light,” said Mohammed Hassan, the paper’s corresponding author and associate professor of physics and optical sciences.

In , light is identified by two linked properties that roughly correspond to a particle’s position and intensity—but can never be known with perfect precision, a concept known as uncertainty. The product of these two measurements cannot fall below a certain threshold, much like the fixed amount of air in a balloon, with each measurement representing one side of the balloon.

Third dimension of data storage: Physicists demonstrate first hybrid skyrmion tubes for higher-density quantum computing

Typically, the charge of electrons is used to store and process information in electronics-based devices. In spintronics, the focus is instead on the magnetic moment or on magnetic vortices, so-called skyrmions—the goal is smaller, faster, and more sustainable computers. To further increase storage density, skyrmions will not only be two-dimensional in the future, but will also conquer the third dimension.

Researchers from the Institute of Physics at Johannes Gutenberg University Mainz (JGU) have now succeeded in creating three-dimensional skyrmions, so-called hybrid skyrmion tubes, in synthetic antiferromagnets and have demonstrated for the first time that these skyrmion tubes move differently than two-dimensional skyrmions.

“Three-dimensional skyrmions are of interest for and brain-inspired computing, among other things—here the higher resulting from the third dimension is essential,” says Mona Bhukta from Professor Mathias Kläui’s research group. The results were published on September 26 in Nature Communications.

Harnessing GeSn semiconductors for tomorrow’s quantum world

An international team of researchers from Forschungszentrum Jülich (Germany), Tohoku University (Japan), and École Polytechnique de Montréal (Canada) has made a significant discovery in semiconductor science by revealing the remarkable spin-related material properties of Germanium-Tin (GeSn) semiconductors.

Semiconductors control the flow of electricity that power everyday technology all around us (such as cars and computers). However, technology is progressing at such a breakneck speed that it is straining current technologies.

“Semiconductors are approaching their physical and energy-efficiency limits in terms of speed, performance, and ,” says Makoto Kohda from Tohoku University. “This is a huge issue because we need semiconductors that can keep up as we shift to more demanding needs such as 5G/6G networks and the increased use of artificial intelligence.”

Chip-based phonon splitter brings hybrid quantum networks closer to reality

Researchers have created a chip-based device that can split phonons—tiny packets of mechanical vibration that can carry information in quantum systems. By filling a key gap, this device could help connect various quantum devices via phonons, paving the way for advanced computing and secure quantum communication.

“Phonons can serve as on-chip quantum messages that connect very different quantum systems, enabling hybrid networks and new ways to process in a compact, scalable format,” said research team leader Simon Gröblacher from Delft University of Technology in the Netherlands.

“To build practical phononic circuits requires a full set of chip-based components that can generate, guide, split and detect individual quanta of vibrations. While sources and waveguides already exist, a compact splitter was still missing.”

Physicist: After 33 billon years, universe ‘will end in a big crunch’

The universe is approaching the midpoint of its 33-billion-year lifespan, a Cornell physicist calculates with new data from dark-energy observatories. After expanding to its peak size about 11 billion years from now, it will begin to contract – snapping back like a rubber band to a single point at the end.

Henry Tye, the Horace White Professor of Physics Emeritus in the College of Arts and Sciences, reached this conclusion after adding new data to a model involving the “cosmological constant” – a factor introduced more than a century ago by Albert Einstein and used by cosmologists in recent years to predict the future of our universe.

“For the last 20 years, people believed that the cosmological constant is positive, and the universe will expand forever,” Tye said. “The new data seem to indicate that the cosmological constant is negative, and that the universe will end in a big crunch.”

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