Some of the fluid is lost into the drain. The wormhole is like a drain.
In 1935, Einstein unknowingly planted two seeds in the same soil — entanglement and wormholes — that physicists are only now learning may be the same root. A team at the University of New Brunswick has used the hydrogen atom, the most precisely measured object in physics, to test whether these two ideas are truly one: the ER = EPR conjecture. Their findings do not confirm the theory, but they do something equally important — they constrain it with extraordinary force, placing the burden of proof squarely on the theory itself to become precise enough to be tested.
- A conjecture uniting quantum entanglement with wormholes — two of physics' most disruptive ideas — has gone untested for over a decade, leaving a tantalizing gap between theory and experiment.
- Researchers found that if ER = EPR is true, hydrogen's electron should effectively lose charge into a wormhole, subtly distorting the atom's energy structure in ways that have never, in any measurement, been seen.
- The silence in the data is deafening: any wormhole effect must be at least a million — and possibly a billion — times weaker than theoretical intuition would naturally predict.
- The experiment is now more precise than the theory it is testing, creating a strange inversion where the instruments are ready but the conjecture is not yet well-formed enough to say what they should find.
- Heavier atoms and entanglement experiments are being eyed as the next arenas, with the possibility that a positive signal would constitute the first observational evidence of quantum gravity in atomic structure.
In 1935, Einstein published two papers that would spend decades as strangers to each other. One described entanglement — correlated particles defying distance. The other introduced wormholes — tunnels through spacetime. In 2013, physicists Maldacena and Susskind proposed they might be the same thing. The ER = EPR conjecture suggested entanglement and wormholes were two faces of a single phenomenon, a potential bridge between quantum mechanics and general relativity.
A team at the University of New Brunswick has now subjected this conjecture to empirical scrutiny using the hydrogen atom — one proton, one electron, and the most precisely characterized system in all of experimental physics. Their reasoning was elegant: proton and electron are inherently entangled by their bond. If ER = EPR holds, that entanglement should manifest as a wormhole between them, and some of the electron's electric field should drain into it, weakening its effective charge in ways measurable through hydrogen's hyperfine structure.
Neither predicted effect — a weakened hyperfine splitting nor a residual net charge — has ever been observed. The constraints are severe: any such effect must be at least a million times smaller than natural theoretical estimates, possibly a billion times smaller still. Yet the deeper paradox is this: the experiment is now more precise than the theory it tests. As Ph.D. student Irfan Javed noted, the conjecture is not yet stated precisely enough to predict what magnitude of effect should exist.
The path forward runs through heavier atoms like cesium and rubidium, and through entanglement experiments originally designed for other purposes. But the stakes are clear. If the conjecture ever survives such tests, it would offer the first observational evidence that entangled particles are genuinely connected through the geometry of spacetime — a true meeting point between the quantum world and the fabric of the universe itself.
In 1935, Einstein published two papers that would echo through physics for nearly a century. One described how entangled particles could exhibit correlated behavior across any distance—what he famously called spooky action at a distance. The other introduced wormholes: theoretical tunnels connecting distant regions of spacetime. For decades, these remained separate ideas. Then in 2013, physicists Juan Maldacena and Leonard Susskind proposed something audacious: what if they were the same thing? What if entanglement and wormholes were two descriptions of a single phenomenon? The ER = EPR conjecture, as it came to be known, suggested a bridge between quantum mechanics and general relativity—two pillars of physics that have resisted unification.
Now a team at the University of New Brunswick has put this conjecture to an empirical test, using the most precisely measured system in all of physics: the hydrogen atom. Their findings, published in Physical Review Letters, reveal something striking. If the ER = EPR conjecture is true, it would require observable changes to hydrogen's structure—changes that have never been detected. The constraints are severe: any such effect would have to be at least a million times weaker than theory would naturally predict, and possibly a billion times smaller still.
The hydrogen atom is deceptively simple: one proton, one electron, bound by electric attraction. Yet it is also the most scrutinized object in experimental physics. Its energy levels are known to fifteen significant figures. Its hyperfine structure—the subtle energy shifts arising from the magnetic interaction between proton and electron spins—has been measured to twelve significant figures. This precision is the key. In a system this well-characterized, even tiny deviations from theory become visible.
The researchers, including Ph.D. student Irfan Javed and Professor Edward Wilson-Ewing, reasoned as follows: the proton and electron in hydrogen are intrinsically entangled simply by being bound together. If the ER = EPR conjecture is correct, this entanglement should manifest as a quantum wormhole connecting them. And if a wormhole exists, some of the electron's electric field should leak into it—like fluid draining into a sink, as Wilson-Ewing put it. The proton, being much larger, would not be affected. This leakage would weaken the electron's effective charge, an effect that should be detectable in hydrogen's hyperfine structure.
To test this, the researchers built a mathematical framework based on two assumptions. First, the amount of electric field leaking into the wormhole would be proportional to the entanglement entropy between proton and electron—a measure of how strongly they are entangled. Second, this effect would only impact point particles, not composite objects like the proton. Under these assumptions, they calculated what signatures ER = EPR would leave in hydrogen's spectrum. They found two: the hyperfine splitting between entangled and unentangled spin states should weaken, and the atom should carry a tiny net charge despite being electrically neutral to twenty decimal places.
Neither effect has ever been observed. The measurements place extraordinarily tight constraints on the conjecture. If the effect exists at all, it must be vastly smaller than natural estimates would suggest. "The observational constraints are very strong," Javed said. "The current limitation is theoretical, since the ER = EPR conjecture is not yet stated in a sufficiently precise fashion to predict how strong the effect should be." This is the paradox: the experiment is precise enough to rule out large effects, but the theory is not yet precise enough to say what size effect should exist.
The work opens new directions. Heavier atoms like cesium and rubidium, whose spectra are measured with similar precision and which are easier to trap experimentally, could yield even tighter constraints. Entanglement witness experiments originally designed to probe quantum gravity could be adapted to test ER = EPR through electrical interactions. But the deeper significance lies in what success would mean. If the conjecture survives such tests, it would provide the first observational evidence that entangled particles are connected by quantum wormholes—that entanglement and spacetime connectivity are linked. It would be evidence of a quantum gravity phenomenon, a genuine bridge between the quantum world and the geometry of spacetime itself.
Citações Notáveis
I had always found the ER = EPR conjecture quite intriguing. Previous work on the consequences of the conjecture for charged particles got me interested in the attempt to put it to test.— Irfan Javed, Ph.D. student, University of New Brunswick
The observational constraints are very strong. The current limitation is theoretical, since the ER = EPR conjecture is not yet stated in a sufficiently precise fashion to predict how strong the effect should be.— Irfan Javed
A Conversa do Hearth Outra perspectiva sobre a história
Why hydrogen? Why not test this conjecture with something else?
Because hydrogen is the most precisely measured system we have. We know its properties to fifteen significant figures. Any effect from a wormhole would have to be incredibly subtle, and only in a system this well-characterized could we hope to see it.
So you're saying the electron and proton are already entangled, just by being bound together?
Exactly. We don't need to prepare them in any special way. The moment they form a hydrogen atom, they're entangled. That makes every hydrogen atom a natural probe of whether entanglement and wormholes are connected.
And if the wormhole exists, the electron's charge leaks away into it?
That's the hypothesis. Some of the electron's electric field would vanish into the wormhole, like water draining into a sink. The proton is too large to be affected. So we'd see a measurable weakening of the electron's effective charge.
But you didn't see that.
We didn't. And the constraints are severe. Any effect would have to be a billion times smaller than we'd naturally expect. That doesn't disprove the conjecture, but it does tell us something important: if it's true, the effect is far more subtle than the theory currently suggests.
So what happens next?
We test heavier atoms, we refine the theory, we look for other signatures. The conjecture is too interesting to abandon. If it's right, it means entanglement and spacetime are fundamentally connected—that would be revolutionary.