What happens to matter when it’s crushed beyond the point where atoms can exist? Inside a neutron star, the densest visible object in the universe, matter is compressed into states so extreme that physicists still don’t fully understand what’s there.
In this calm long-form space documentary, we take a journey layer by layer through the interior of a neutron star — from the crystalline crust where exotic nuclei form structures unlike anything on Earth, through the bizarre \.
Let’s say you have a probabilistic computer with a single bit of memory. Some algorithms on the computer will stochastically flip the single bit of memory such that its new value will be uniformly distributed with a 50% chance of being 0 and a 50% chance of being 1. Other programs will place it into a degenerate distribution, meaning it either has 100% chance of being 0 every time you run the program, or other programs will produce 1 100% of the time.
A magician tells you to run one of the programs in one of the two categories of your choosing and then copy the computer’s memory state onto a thumb drive and hand it to him. You pick one, run the program, copy the bit of the memory to your thumb drive, then hand it to the magician. The magician then does something with the thumb drive you cannot see, then looks up at you and tell you exactly what category the program you ran to produce that bit came from.
Curious, you repeat this many times over: you run a program from one of the two categories (degenerate or uniform), copy the bit value produced from the algorithm, and then hand the thumb drive to the magician. Each and every time he always correctly guesses which category of program was ran to produce it.
A 19th-century theory of elasticity inspires a new way to analyze a quantum phase transition that has become central to modern quantum materials research.
When a crystalline metal enters a so-called nematic state, the onset of strong fluctuations among interacting electrons spontaneously breaks the crystal’s rotational symmetry and distorts both the physical lattice and the notional Fermi surface. This transition, known as nematic criticality, has been observed near the onset of superconductivity in cuprates, pnictides, and twisted bilayer graphene and could hold the key to explaining these poorly understood forms of superconductivity. Now Joe Meese and Rafael Fernandes of the University of Illinois-Champaign have proposed that nematic criticality is more selective in how it breaks rotational symmetry than previously assumed [1, 2]. The selectivity arises not from a novel microscopic mechanism but from a geometric constraint.
Nematic order typically develops spontaneously upon cooling; hydrostatic pressure can shift the transition, while uniaxial stress can tune the transition or induce nematicity by linearly coupling to lattice strain. Because of this connection, nematic order obeys the same mechanical laws as other continuous lattice deformations do. Consequently, as Meese and Fernandes showed, nematic order splits into two classes. One class is compatible with the lattice and can turn critical; the other is incompatible with the lattice and is therefore suppressed (Fig. 1). In the conventional picture, the energy cost of completing a nematic transition is “softened”—that is, reduced by the emergence of fluctuations as the transition is approached. That condition remains true in Meese and Fernandes’ picture, but the softening is not spread over all the possible distortions allowed by symmetry. Rather, elasticity itself selects the modes that participate in nematic criticality.
Few concepts in physics are as familiar, yet as enigmatic, as time. In Einstein’s theory of relativity, time is not absolute: its passage depends on motion and gravity. But when combined with quantum physics, this relativistic form of time becomes even more counterintuitive.
According to quantum theory, the flow of time itself may exist in a genuine quantum superposition, ticking faster and slower at the same time. Now, a new paper titled “Quantum signatures of proper time in optical ion clocks”, published in Physical Review Letters, shows that this striking possibility may soon be tested in the laboratory.
In this work, a team led by Assistant Professor of theoretical physics Igor Pikovski at Stevens Institute of Technology, in collaboration with experimental groups of Christian Sanner at Colorado State University and Dietrich Leibfried at the National Institute of Standards and Technology (NIST), explores quantum aspects of the flow of time and how they can be accessed with atomic clocks.
Two independent research teams have each demonstrated collisional quantum gates using fermionic atoms: a long-sought milestone in quantum computing where logic operations are performed through the direct physical overlap of atoms, rather than forcing them into fragile, highly excited states.
The studies have been published simultaneously in Nature: the first led by Petar Bojović at the Max Planck Institute for Quantum Optics in Garching, Germany, and the second by Yann Kiefer and colleagues at ETH Zurich, Switzerland.
A joint theoretical study by the University of Innsbruck and Zhejiang University has uncovered the microscopic origin of a striking quantum phenomenon: a periodically driven gas of ultracold atoms that simply refuses to heat up, defying classical expectations.
Push a swing repeatedly in rhythm, and it swings higher and higher, absorbing more and more energy. A quantum gas, however, can behave very differently. Under periodic kicks, quantum interference can freeze energy absorption entirely, a phenomenon known as dynamical localization. Whether this survives when particles interact with each other has been a long-standing open question. A 2025 experiment by the research group of Hanns-Christoph Nägerl at the Department of Experimental Physics confirmed that it can. But the microscopic reasons remained until now unclear.
A new theoretical study by Prof. Lei Ying’s team at Zhejiang University, in collaboration with Prof. Hanns-Christoph Nägerl’s group at the University of Innsbruck, published in Physical Review Letters, provides the missing explanation. The team developed a mathematical framework that transforms the complex-driven many-body problem into a tractable lattice model. This reveals that interactions introduce a universal power-law structure that reshapes localization—and ultimately drives its breakdown at intermediate interaction strengths.
Recent findings from research we have been carrying out at the Large Hadron Collider (LHC) at Cern in Geneva suggest that we might be closing in on signs of undiscovered physics.
If confirmed, these hints would overturn the theory, called the Standard Model, that has dominated particle physics for 50 years. The findings suggest the way that specific sub-atomic particles behave in the LHC disagrees with the Standard Model.
Fundamental particles are the most basic building blocks of matter—sub-atomic particles that cannot be divided into smaller units. The four fundamental forces—gravity, electromagnetism, the weak force and the strong force—govern how these particles interact.
An international research team of the A1 Collaboration at the Mainz Microtron (MAMI) of Johannes Gutenberg University Mainz (JGU) has succeeded in determining the binding energy of the hypertriton with unprecedented precision. This experiment provides crucial new insights into the interaction between hyperons and nucleons—an aspect of the strong nuclear force that has so far remained insufficiently understood. The results show that the hypertriton is significantly more strongly bound than many earlier experiments suggested. The journal Physical Review Letters has recently published the study.
The hypertriton is the lightest known hypernucleus. It is an artificially produced hydrogen isotope that, in addition to a proton and a neutron, contains a so-called Lambda hyperon. Although hypernuclei exist for only a few hundred trillionths of a second, they provide unique insights into the strong interaction—the fundamental force that binds atomic nuclei and underlies the structure of matter in the universe. The hypertriton plays a key role in this context: consisting of only three particles, it is ideally suited for precise tests of theoretical models of the hyperon-nucleon interaction.
“Precisely because the hypertriton has such a simple structure, its properties are highly sensitive to the underlying nuclear forces,” explained Prof. Dr. Patrick Achenbach from the Institute for Nuclear Physics at JGU. “Our new measurement clearly shows that this interaction is stronger than long assumed—an important step toward resolving a puzzle that has persisted for many years.”
A team of international researchers, including an Aston University researcher, has cracked the code on how “breather” laser pulses work, creating a single mathematical model that explains two completely different laser behaviors for the first time. Ultrafast lasers emit extremely short pulses of light, lasting only picoseconds or femtoseconds, making them essential for applications ranging from eye surgery and biomedical imaging to precision materials processing and advanced manufacturing.
The work is published in the journal Physical Review Letters. By understanding laser behaviors better, scientists will be able to control them, making lasers more reliable and better suited to specific applications.
An ultrafast laser produces pulses of light that circulate within the laser cavity, where they can evolve into stable structures called solitons. Solitons tend to maintain their shape as they travel, unlike conventional light pulses which spread out. Usually, these solitons are identical and regular, like a heartbeat, known as steady-state emission. In a “breather” laser, the solitons change over time and successive cavity round trips, growing and shrinking before repeating the cycle, like a breathing pattern. This is an example of a non-equilibrium state, where the laser output does not remain constant but keeps evolving over time.
Superconducting qubits—bits of quantum information—have been widely considered a promising technology for moving quantum computing forward. But there’s still much work to be done before they can be brought out of a near absolute zero temperature environment. The lab of Professor Hong Tang has recently published two studies that advance the technology.
To solve practical problems, quantum processors need a lot of qubits—up to thousands to millions. Such a large number of qubits requires significantly complex wiring and a way to store them at a temperature colder than deep space. This is complicated by the physical size of the cryogenic devices, known as dilution refrigerators, that maintain qubits at a temperature just above absolute zero. In a study published in Nature Photonics, Tang’s research team has found a way around this obstacle.
A flexible and cost-effective solution is to build a quantum network by connecting qubits inside separate refrigerators. Connecting qubits with standard coaxial cables, however, wouldn’t work if those cables were kept in a room temperature environment. And storing them all in one very cold room would be near impossible. Even under an optimistic assumption of 1,000 qubits per refrigerator, scaling to 1 million qubits would require linking 1,000 refrigerators—an arrangement that is physically impractical within a single room.