🐱 Oxford Physicists Just Made Schrödinger’s Cat Even Weirder

Schrödinger’s cat was never really about a cat. It was a way to show how strange quantum mechanics becomes when one object is treated as being in two states at once.

Now physicists at the University of Oxford have created a new family of “cat-like” quantum states — but with an extra twist: the two parts of the superposition are not ordinary, classical-looking wave packets. They are already deeply quantum objects.

In standard lab versions of Schrödinger-cat states, researchers usually combine coherent states — the closest thing quantum physics has to classical motion. The Oxford team went further. Using a single trapped strontium-88 ion, they built superpositions from squeezed, trisqueezed and quadsqueezed motional states: exotic states where quantum uncertainty is reshaped in unusual ways.

The setup is elegant. The ion’s internal electronic state acts like a qubit, while its motion behaves like a quantum harmonic oscillator — a system that can occupy many energy levels. By entangling these two parts and then performing a mid-circuit measurement, the team could “sculpt” the ion’s motion into highly programmable quantum superpositions.

Why is this interesting?

• The states are built from nonclassical components, not just classical-like wave packets
• Their size, orientation and separation can be tuned experimentally
• Wigner-function measurements showed interference and negativity — signatures of genuinely quantum behavior
• Some states displayed striking geometric patterns, including sixfold symmetry in a trisqueezed example
• At the same average energy, these states can be more “quantum-resourceful” than standard cat states or Fock states

This matters because future quantum computers may not rely only on simple qubits. Quantum oscillators can store information across many energy levels, opening a richer route toward bosonic quantum error correction — where information is encoded in oscillator states rather than many separate physical qubits.

It is still early-stage physics, not a ready-made quantum computer. But it gives researchers a new way to build, control and study quantum states that sit far beyond everyday intuition.

And it brings us back to the original question Schrödinger wanted to provoke:

Where does the quantum world end — and the classical world begin?

Source: https://doi.org/10.1103/k1xk-yt42

#QuantumPhysics #SchrodingersCat #QuantumComputing #Physics #Oxfordx #science

⚛️ Physicists Create a Strange New Quantum State — the “Fractional Fermi Sea”

Quantum simulators are usually built to recreate known physics in a clean, controllable setting. But a team at the University of Innsbruck has pushed the idea further: they engineered a highly unusual quantum state that appears to go beyond one of the standard frameworks for one-dimensional matter.

The researchers used ultracold cesium atoms confined in one-dimensional tubes and drove them far from equilibrium by cycling the interactions between strongly repulsive and strongly attractive regimes. Normally, this kind of forcing might be expected to heat the system and wash out any structure.

Instead, the atoms reorganized into something unexpectedly ordered.

The state is called a “fractional Fermi sea” — a highly excited, yet stable configuration where particles behave as if the usual occupancy rules have been replaced by a reduced, fractional version. It does not literally rewrite the Pauli exclusion principle, but it realizes behavior long associated with Haldane’s generalized exclusion statistics: particles filling available states in a fractional way.

What makes this especially interesting is that the correlations do not fit neatly into the familiar Tomonaga–Luttinger liquid picture, the classic theory used to describe many one-dimensional quantum systems. The particles show distinctive Friedel oscillations — ripples in density correlations — and decay patterns that point to a new kind of critical quantum phase.

In simple terms: the system is not cold, calm, and sitting in its lowest-energy state. It is highly excited — but not chaotic. Hidden order emerges from the drive.

The theoretical work has now been published in Physical Review Letters, while the companion experimental realization is available as a preprint.

Why it matters: quantum simulators are no longer just “physics replay machines.” They can create and probe states of matter that may be extremely hard — or impossible — to find naturally, opening new ways to study strongly correlated systems, exotic statistics, and future quantum technologies.

The big takeaway: sometimes the deepest order in quantum matter appears not when everything is perfectly still, but when a system is pushed far from equilibrium and refuses to fall apart.

📄 Theory paper: Physical Review Letters 136, 230402 (2026)
https://doi.org/10.1103/j3s5-gjpf

📄 Experimental preprint:
https://arxiv.org/abs/2602.17657

📖 Summary:
https://www.uibk.ac.at/en/newsroom/2026/a-novel-critical-quantum-phase/

#QuantumPhysics #CondensedMatter #QuantumSimulation #Physics

⏳ Scientists Found a Way to Make Quantum Time Look Like It Runs Backward

At our everyday scale, time has a clear direction. Eggs break, coffee cools, and no one has ever un-spilled a glass of water.

But at the quantum scale, the story is stranger. Many fundamental equations work just as well forward or backward in time. The arrow of time appears when a system is measured — because measurement randomly disturbs its state.

Now researchers from Los Alamos National Laboratory, NIST, and the University of Maryland have developed a theoretical control method that can reshape that arrow.

Their idea is based on a “control Hamiltonian” — a precisely designed sequence of fields and pulses that mimics and counteracts the random disturbance caused by quantum measurement. With the right feedback, the system’s trajectory can be made to look as if it is moving backward rather than forward.

To be clear: this is not a time machine.

No one reversed time for people, objects, or the universe. The work shows that, in a monitored quantum system, the appearance of time’s direction can be weakened, blurred, or even inverted.

The team also used the framework to design a quantum version of Maxwell’s demon — a measurement-powered engine that could, in principle, extract useful energy from the act of observation itself. That energy might one day help drive quantum processes or be stored in a quantum battery.

The caveat: this is still mostly a theoretical result. Experimental tests are planned for superconducting qubits, where fast feedback and quantum Maxwell’s demon setups are already technically plausible.

Why it matters: better control over quantum measurement could help with quantum state preparation, more stable quantum computers, and new ways to manage energy at the smallest scales.

The big takeaway: the arrow of time may feel absolute in daily life — but in the quantum world, it can become something engineers may learn to control.

📄 Original paper: https://link.aps.org/doi/10.1103/l18s-9vmh
📖 Los Alamos summary: https://www.lanl.gov/media/news/0319-reshaping-quantum-arrow
📖 ScienceDaily summary: https://www.sciencedaily.com/releases/2026/06/260625014802.htm

#QuantumPhysics #ArrowOfTime #QuantumComputing #Physics

💻 Classical Computers Just Overturned a Major Quantum Advantage Claim

In 2025, researchers used D-Wave’s Advantage2 quantum annealer to simulate the dynamics of hundreds of interacting qubits — and argued that the task was beyond the reach of classical computers.

A team from the Flatiron Institute and Boston University has now reproduced those results using classical algorithms and relatively modest hardware. Some of the initial calculations even ran on a personal laptop.

The challenge involved quantum spin glasses: disordered systems in which hundreds of interacting qubits evolve across two- and three-dimensional lattices. Tracking the complete quantum wave function directly would require an amount of memory that grows exponentially with the number of qubits.

The researchers avoided that explosion using tensor networks — mathematical structures that compress a quantum state by retaining its most important correlations.

Think of it as a highly specialized zip file for quantum information.

They combined tensor networks with belief propagation, an algorithm developed in the 1980s and recently adapted for quantum systems. The calculations were implemented using ITensor, a high-performance tensor-network software library.

The classical simulations:

• reproduced the quantum computer’s results
• matched theoretical predictions and exact benchmarks
• scaled to systems containing hundreds of qubits
• captured quantum dynamics in complex 3D lattice geometries

There is one important caveat: the entire study was not completed on an ordinary laptop. A laptop was sufficient for some early calculations, while the largest simulations required more powerful conventional processors and GPUs.

Still, the result directly challenges the earlier claim that this particular problem was beyond classical computation.

It does not mean quantum computers are useless. It means that demonstrating genuine quantum advantage requires beating the best classical algorithms available — not merely the best ones researchers happened to test previously.

The boundary between classical and quantum computing is not fixed. Every improvement in quantum hardware gives classical researchers a new target, while every better classical algorithm raises the bar for quantum advantage.

Sometimes the strongest competitor to a quantum computer is not another quantum computer.

It is better mathematics.

📄 Paper: Dynamics of disordered quantum systems with two- and three-dimensional tensor networks
https://www.science.org/doi/10.1126/science.adx2728

#QuantumComputing #Physics #TensorNetworks #ClassicalComputing #QuantumPhysics

⚛️ Physicists May Have Finally Found Matter Made Mostly of Force

For nearly 50 years, physicists have searched for a bizarre particle predicted by quantum chromodynamics: the glueball.

Ordinary matter is built from quarks. Gluons are the particles that carry the strong nuclear force and “glue” quarks together inside protons and neutrons. But because gluons also interact with each other, theory predicts that they should be able to bind together — creating a particle with no ordinary valence quarks at its core.

Now the BESIII experiment in China says X(2370), a particle first detected in 2011, finally fits the bill. Using a dataset of roughly 10 billion J/ψ particles, researchers have gradually established its mass, spin and parity, unusual decay patterns, and now its flavor-singlet behavior. Taken together, the team argues that these properties are best explained if a pseudoscalar glueball is the dominant component of X(2370).

That distinction matters: scientists are not yet claiming X(2370) is a perfectly pure ball of gluons. Quantum particles can mix with other states, and the newest analysis is currently a preprint awaiting peer review. But independent physicists describe it as the strongest glueball evidence produced in decades.

If confirmed, it would be an extraordinary demonstration of one of QCD’s strangest predictions: the particles responsible for holding matter together can apparently bind together themselves.

Matter made mostly from the force that binds matter.

Physics occasionally writes its own headlines.

#Physics #ParticlePhysics #QuantumPhysics #QCD #Glueball #Science

https://english.ihep.cas.cn/nw/han/y26/202608/t20260804_1186878.html

🌌 Scientists May Have Seen “Empty” Space Bend Light

Almost 90 years ago, quantum theory made a bizarre prediction: a perfect vacuum is not truly empty. Under an unimaginably strong magnetic field, empty space itself should behave a little like a transparent material — changing the way light passes through it.

Now astronomers may finally have seen the effect in nature.

Researchers studied 1E 1547.0−5408, a magnetar — an ultra-dense neutron star with a surface magnetic field above 100 trillion gauss. Using NASA’s IXPE X-ray telescope together with NICER and Australia’s Parkes/Murriyang radio telescope, the team measured extraordinarily polarized X-rays: about 65% at 2 keV, rising to nearly 80% during parts of the star’s rotation.

Ordinary models struggled to reproduce what they saw. But when the researchers included vacuum birefringence — a prediction of quantum electrodynamics in which extreme magnetic fields make the quantum vacuum refract different polarizations of light differently — the observations fell naturally into place.

The idea goes back to work by Werner Heisenberg and Hans Euler in the 1930s. In modern quantum field theory, even a vacuum contains fluctuating quantum fields, and extreme magnetic fields can alter how photons propagate through them.

This is not yet considered a definitive detection. The researchers say more observations and improved simulations are needed to rule out competing explanations.

But if confirmed, the result would turn one of the strangest properties of quantum theory into something astronomers can actually observe across the Galaxy.

Empty space, apparently, may not be very empty at all.

#Physics #QuantumPhysics #Magnetar #Astronomy #QED #Science

https://www.nature.com/articles/s41586-026-10859-z

⚛️ Scientists Found Quantum Entanglement Inside Higgs Boson Decays

Einstein famously disliked quantum entanglement enough to call it “spooky action at a distance.”

Now physicists have found strong evidence that the same bizarre quantum connection survives inside some of the most violent particle collisions humans can create.

Using the ATLAS Experiment detector at the Large Hadron Collider, researchers studied Higgs bosons decaying into pairs of Z bosons — massive particles that exist for only a tiny fraction of a second.

The question was simple:

Are the quantum states of those two particles independent — or entangled?

The Z bosons disappear far too quickly to measure directly. Instead, researchers reconstructed their spin states from the directions of the electrons and muons produced when they decayed.

The resulting correlations strongly favored quantum entanglement. A statistical analysis rejected a separable, non-entangled description at 4.7 sigma — strong evidence, although just below particle physics’ conventional 5-sigma discovery threshold.

There is another unusual detail.

A Z boson has three possible spin projections. So instead of the familiar two-state qubits used in quantum computing, the entangled Z bosons behave mathematically as qutrits — three-state quantum systems.

Entanglement itself is not new. Scientists have demonstrated it spectacularly with photons, atoms and other systems.

What is new is where it survived.

These Z bosons were created in proton collisions at energies of 13 and 13.6 TeV. They are enormously heavier and vastly shorter-lived than the particles used in traditional entanglement experiments. The result provides the first measurements of entanglement between pairs of Z bosons and strong evidence for entanglement between massive vector bosons at the electroweak scale.

Quantum mechanics, in other words, does not become less weird when you turn the energy up.

It just gets a much bigger laboratory.

#QuantumPhysics #HiggsBoson #CERN #LHC #QuantumEntanglement #Physics #Science

https://journals.aps.org/prl/abstract/10.1103/y1nh-1b82

⚛️ Scientists Watched Matter “Appear” Inside a Quantum Computer

Pull two quarks apart and something deeply strange happens.

You never actually get two isolated quarks.

Instead, the energy binding them grows — almost as if an invisible string were being stretched between them. Eventually, storing more energy in that string becomes so expensive that nature takes another option:

it creates a new particle–antiparticle pair.

The string breaks.

This process, called string breaking, is fundamental to the strong nuclear force and probably played an important role in how matter evolved in the extremely hot early universe.

But calculating its real-time quantum dynamics is extraordinarily difficult.

So researchers from Duke University, the University of Maryland, Oxford, Caltech, Cornell and KU Leuven built a miniature analogue of the problem inside a quantum machine.

They programmed a chain of 13 trapped ytterbium ions to behave according to a simplified lattice gauge theory.

The ions were not literally turned into quarks.

Instead, their quantum states encoded the particles, fields and “string” connecting them — allowing researchers to watch the simulated system evolve with both spatial and temporal resolution.

And then the string broke.

New effective particle pairs appeared and propagated through the simulated system, reproducing the essential quantum dynamics physicists wanted to study.

But the experiment also produced a surprise.

The conventional expectation was that particle pairs would spontaneously appear throughout the string through a process related to the Schwinger mechanism.

Instead, the researchers observed pairs forming preferentially near the two ends of the string, then spreading inward.

Their calculations indicate this is a distinct, previously unobserved mechanism for dynamical string breaking.

This is not a simulation of the full Standard Model, and no real matter was created inside the computer. The experiment used a simplified 1+1-dimensional Z₂ gauge theory, and today’s classical computers can still reproduce a system this small.

The real prize comes later.

As quantum simulators grow, they could attack versions of these problems that conventional supercomputers cannot efficiently calculate — potentially letting physicists experimentally explore the quantum dynamics of particle collisions and conditions resembling the universe shortly after the Big Bang.

We built computers out of quantum mechanics.

Now we’re beginning to use them to ask quantum mechanics how the universe built matter.

#QuantumComputing #QuantumPhysics #ParticlePhysics #BigBang #Physics #Science

https://doi.org/10.1038/s41567-026-03422-0

⚛️ Scientists Have Built the World’s First Nuclear Clocks. They Could Change How We Measure Time.

For decades, the world’s most precise clocks have measured time using electrons moving between quantum energy levels inside atoms.

Now, two independent teams in Vienna and Beijing have demonstrated something physicists have pursued for more than 20 years:

Clocks that measure time using the atomic nucleus itself.

And the difference could be revolutionary.

Atomic nuclei are more than 10,000 times smaller than atoms and are generally much less sensitive to external electromagnetic disturbances.

That makes nuclear transitions exceptionally promising as stable frequency references.

The challenge? Almost every nuclear transition requires enormous energies, far beyond what conventional lasers can provide.

But one isotope is special: thorium-229.

Its nucleus has an unusually low-energy excited state that can be accessed using ultraviolet laser light at approximately 148 nanometers.

Researchers embedded thorium-229 nuclei inside tiny calcium fluoride crystals and developed lasers capable of detecting their nuclear transitions.

Then came the breakthrough.

They used the nuclear transitions themselves to automatically stabilize the laser frequency.

The result: two independently demonstrated, functioning nuclear clocks.

The European system operated continuously for approximately 24 hours, achieving fractional frequency instability approaching 10⁻¹⁵ after a day of averaging.

That’s an extraordinarily small fluctuation — although today’s best optical atomic clocks are still substantially more stable.

But the most exciting application might have nothing to do with telling time.

One team has already used its nuclear clock to search for dark matter.

Some theories predict that ultralight dark matter could cause tiny oscillations in fundamental physical constants, subtly changing how atomic nuclei behave.

By comparing nuclear and atomic clocks, physicists can search for these otherwise invisible effects.

The experiment found no dark matter signal, but it established new constraints on certain theoretical models.

And this is only the beginning.

Future nuclear clocks could potentially improve satellite navigation, measure gravitational effects with extraordinary precision and test whether the fundamental constants of physics really remain constant.

For thousands of years, humanity has built better clocks to understand time.

Now we’re building clocks that might help us understand the universe itself.

#Physics #QuantumPhysics #NuclearPhysics #AtomicClocks #DarkMatter #QuantumTechnology #Science

https://www.nature.com/articles/s41586-026-11084-4

⚛️ Google Just Reduced a Critical Quantum Computing Error by 40 TIMES
Quantum computers have a fundamental problem.
They can potentially perform calculations beyond the reach of classical machines, but the quantum states they rely on are incredibly fragile.
Even tiny disturbances can introduce errors, making large-scale quantum calculations extremely difficult.
Now, researchers at Google Quantum AI have demonstrated a breakthrough that could help overcome one of the biggest obstacles.
They reduced errors in a critical quantum computing resource by approximately 40 times.
In a new study published in Science, researchers used Google's Willow quantum processor to demonstrate a technique called magic state cultivation.
Despite the name, there's nothing supernatural about it.
Magic states are specially prepared quantum states that enable certain operations essential for universal quantum computing.
Producing them reliably has been one of the field's biggest technical challenges.
The researchers developed a method to create these states, detect errors and discard unsuccessful attempts.
The result: quantum states with approximately 99.99% fidelity.
That means the prepared states matched their intended quantum states with extraordinarily high accuracy.
But the breakthrough goes beyond simply reducing errors.
The team also demonstrated that these refined states could be transferred between two different quantum error-correction systems — an important step toward integrating them into larger quantum computers.
And here's why this matters.
Some estimates suggest that producing reliable magic states could consume the overwhelming majority of a future fault-tolerant quantum computer's hardware resources.
Making their production more efficient could dramatically change the economics and engineering requirements of quantum computing.
Important caveat: The 40-fold improvement applies to the error rate of these particular quantum states, not the overall error rate or computing speed of Willow. Only about 8% of preparation attempts passed the researchers' strict checks. This is a hardware proof of principle, not a demonstration of a large-scale, fault-tolerant quantum computer.
Nevertheless, the implications are enormous.
Future quantum computers could help simulate complex molecules, discover new materials and investigate physical systems that conventional supercomputers struggle to model.
For decades, scientists have been trying to make quantum computers powerful enough to perform useful calculations.
Now they're getting better at making quantum information reliable enough to trust.
And that may prove just as important.
Could the biggest breakthrough in quantum computing turn out to be not more qubits — but fewer errors?
#Science #QuantumComputing #Physics #Google #QuantumPhysics #Technology #Innovation
https://doi.org/10.1126/science.aee7961