A boundary where the wave-like properties of electrons simply ceased to exist
In a modest Amsterdam laboratory, physicists constructed a stand-in for one of the universe's most impenetrable mysteries — a black hole rendered in miniature through a chain of atoms — and watched it emit the faint thermal glow that Stephen Hawking predicted half a century ago but no telescope has ever confirmed. The experiment, led by Lotte Mertens at the University of Amsterdam, did not solve the ancient quarrel between quantum mechanics and general relativity, but it opened a quiet door: a place where that quarrel can be studied on human terms, in controlled conditions, without waiting for the cosmos to cooperate.
- For fifty years, Hawking radiation has remained a theoretical ghost — predicted with confidence, yet never once detected from an actual black hole because the signal is too faint to distinguish from the noise of the universe.
- The tension at the heart of modern physics — general relativity's smooth, curved spacetime crashing against quantum mechanics' probabilistic particle world — becomes unavoidable near black holes, and no unified theory has yet survived the collision.
- Mertens and her team engineered an artificial event horizon using electrons hopping along a single-file atomic chain, tuning the system until a boundary emerged that mimicked the one-way threshold of a real black hole's edge.
- The simulated system produced thermal radiation matching Hawking's predictions, but only under precise conditions — suggesting particle entanglement across the artificial horizon may be the mechanism that generates the radiation in the first place.
- The experiment does not yet bridge quantum gravity's great divide, but it hands physicists something they have never had before: a simple, adaptable laboratory stage on which to rehearse questions that the cosmos has kept just out of reach.
In November 2022, physicists at the University of Amsterdam built something that had never existed before: a laboratory stand-in for a black hole. Lotte Mertens and her team used the simplest possible materials — a single-file chain of atoms — and allowed electrons to hop between them like travelers moving through a line of stations. By carefully adjusting how freely those hops could occur, they engineered an artificial event horizon: not a region of crushed spacetime, but a subtle boundary where the wave-like nature of electrons simply ceased, mimicking the one-way threshold that defines a real black hole.
What the team observed next echoed a prediction that has haunted physics since 1974, when Stephen Hawking proposed that black holes should glow. His reasoning was strange but rigorous: quantum fluctuations near an event horizon can tear apart particle pairs, sending one inward while the other escapes, carrying energy away as faint thermal radiation. No one has ever detected this from a real black hole — the signal is too weak, lost in the noise of the cosmos. But its existence, if confirmed, could illuminate something far larger: a path toward reconciling general relativity and quantum mechanics, two theories that work brilliantly in isolation and contradict each other catastrophically near black holes.
When Mertens's team measured the temperature of their simulated system, they found it rose in ways that matched theoretical predictions for Hawking radiation — but only under specific conditions. The effect emerged only when part of the atomic chain extended beyond the artificial horizon, pointing to entanglement between particles straddling that boundary as a possible engine of the radiation. The thermal signature also depended on the geometry of the simulated spacetime, suggesting Hawking radiation may not always behave the same way in every setting.
The experiment does not solve quantum gravity. But it offers something physicists have lacked: a controlled, adaptable environment where the emergence of Hawking radiation can be studied without the violent dynamics of real black hole formation. Because the system is so simple, it can be modified, replicated, and extended in ways that purely theoretical work cannot. Published in Physical Review Research, the work marks a careful, genuine step toward understanding what happens where the very large and the very small are forced, at last, to meet.
In November 2022, physicists in Amsterdam did something that seemed impossible: they built a black hole in a laboratory and watched it glow. Not a real black hole, of course—those remain locked away in the cosmos, their secrets sealed behind event horizons from which nothing escapes. Instead, Lotte Mertens and her team at the University of Amsterdam created a simulation using the simplest possible materials: a single-file chain of atoms.
The setup was elegant in its restraint. Electrons were allowed to hop from one atom to the next along this chain, like travelers moving down a line of train stations. By adjusting how easily these hops could occur—tuning what physicists call the hopping amplitude—the researchers engineered an artificial event horizon. This wasn't a region of warped spacetime crushing matter into oblivion. It was something far more subtle: a boundary where the wave-like properties of electrons simply ceased to exist, mimicking the one-way barrier that defines a real black hole's edge.
What happened next matched a prediction that had haunted physics for nearly fifty years. In 1974, Stephen Hawking proposed something counterintuitive: black holes should emit radiation. The mechanism seemed almost paradoxical. Quantum fluctuations—the constant jittering of particles and antiparticles that populate empty space—get disrupted by the event horizon's presence. Pairs of particles can be torn apart, with one falling into the black hole while the other escapes, carrying away energy. The result is a faint thermal glow, now called Hawking radiation. No one has ever detected it from a real black hole. The signal is too weak, buried beneath the noise of the universe itself. But if it exists, understanding it could unlock something far larger: a bridge between two theories that have refused to speak to each other for a century.
General relativity describes gravity as the curvature of spacetime itself—a continuous, smooth fabric warped by mass and energy. Quantum mechanics describes the subatomic world as a realm of discrete particles governed by probability. These frameworks work brilliantly in their own domains. But near a black hole, both should apply simultaneously, and they contradict each other. A unified theory of quantum gravity would resolve this tension, but physicists have been unable to construct one. Black holes, being the most extreme objects in the universe, are where this incompatibility becomes impossible to ignore.
Mertens's experiment offered a new way to study the problem without waiting for cosmic observations that might never come. When the team measured the temperature of their simulated system, they found it rose in ways that matched theoretical predictions for Hawking radiation—but only under specific conditions. The effect appeared only when part of the atomic chain extended beyond the artificial event horizon, suggesting that entanglement between particles straddling the boundary might be essential to generating the radiation. The thermal signature also only appeared within a certain range of hopping amplitudes and when the simulated spacetime was flat, implying that Hawking radiation may not always be thermal, and may depend on the geometry of spacetime itself.
What makes this work significant is not that it solves quantum gravity—it doesn't. Rather, it offers a controlled laboratory setting where researchers can study the emergence of Hawking radiation without the chaotic dynamics of actual black hole formation. Because the system is so simple, it can be adapted and modified in countless ways, deployed in different experimental setups, and used to test predictions that would otherwise remain purely theoretical. The researchers wrote that their approach could "open a venue for exploring fundamental quantum-mechanical aspects alongside gravity and curved spacetimes in various condensed matter settings." The work was published in Physical Review Research, and it represents a small but genuine step toward understanding what happens at the intersection of the very large and the very small.
Citas Notables
This can open a venue for exploring fundamental quantum-mechanical aspects alongside gravity and curved spacetimes in various condensed matter settings— The research team
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Why does it matter that they saw this glow in a laboratory? Isn't it just a simulation?
Because Hawking radiation has never been directly observed from a real black hole—it's too faint. This lab version lets us test whether the theory actually works, and under what conditions.
But if it's just atoms in a chain, how is it actually like a black hole?
The artificial event horizon behaves the same way mathematically. Electrons can't cross it, just like nothing can escape a real event horizon. The physics of what happens at that boundary should be the same.
So what did they actually discover that was new?
That particles entangled across the boundary might be what generates the radiation. And that it only appears under certain conditions—not always, not everywhere. That's a constraint on the theory.
Does this solve the problem between quantum mechanics and relativity?
No. But it gives us a way to study the problem in a controlled setting. That's often how breakthroughs happen—you find a simpler system that exhibits the same behavior, then you can experiment with it.
What happens next?
Other labs will probably try variations of this setup. Different materials, different geometries. Each one teaches us something about when and how Hawking radiation emerges.