Is consciousness quantum? Inside the experiment that could find out

A plasma ball with pink and purple filaments of light branching out from its center

One of our hoodies says "Stay present. You build reality." on the back. We meant it as a reminder to look up. Then New Scientist put out a film about physicists who are testing a version of that sentence in a lab, and we went down the rabbit hole. Here's what the experiments show, what they don't, and why we think it's worth your attention.

The idea nobody wanted

In the 1990s, physicist Roger Penrose and anesthesiologist Stuart Hameroff proposed that consciousness isn't only neurons firing. Their theory, called Orchestrated Objective Reduction (Orch OR), says it also depends on quantum events inside microtubules, the tiny protein tubes that give every cell its shape. Penrose, who later shared the 2020 Nobel Prize in Physics for unrelated work on black holes, still puts it bluntly. To do what consciousness does, he says in the film, "you need something beyond ordinary physics."

Most scientists didn't buy it. The brain is warm, wet and noisy, and quantum states are fragile. In 2000, physicist Max Tegmark calculated that any quantum state in a microtubule would fall apart in about a ten-trillionth of a second or less. A thought takes somewhere between a thousandth and a tenth of a second. On those numbers, the quantum part is over long before the thinking starts.

What changed

Nobody has overturned that objection. What changed is that the idea can now be tested, and a few results are stranger than expected.

  • Energy moves oddly in microtubules. In a 2023 study in ACS Central Science, researchers measured how far energy travels through microtubules after light excites them. It went farther than the standard theory predicts, about 6.6 nanometers. When they added two anesthetics, etomidate and isoflurane, it didn't travel as far. Two cautions: this was done on microtubules in a test tube, not in a living brain, and Hameroff and Penrose are among the authors.
  • One prediction has already failed. Deep under the Gran Sasso mountain in Italy, physicists looked for the faint radiation that the simplest version of Penrose's collapse idea says should exist. They didn't find it. Their 2022 paper concludes that this version is very unlikely to be right, and leaves more complicated versions open.

The xenon clue

This is the experiment in the title. Xenon is a gas that barely reacts with anything, and yet it works as a general anesthetic. Breathe enough of it and consciousness switches off, then comes back.

Xenon comes in several versions, called isotopes. Chemically they are the same. The difference is in the nucleus: some isotopes have a quantum property called spin, and some don't. If anesthesia were only chemistry, every isotope should knock you out equally well.

In 2018, a team tested four xenon isotopes on mice. The two with nuclear spin were weaker anesthetics. By the figures reported from that study, it took roughly 40 to 50 percent more gas to get the same effect. One proposed explanation involves pairs of electrons whose spins are linked, the same kind of mechanism thought to help birds sense Earth's magnetic field. That explanation is a model, not a confirmed finding.

It is also one study, in mice, and it needs to be repeated. That is happening now. Hartmut Neven, who founded and leads Google's Quantum AI lab, and neuroscientist Christof Koch are part of a group running the xenon test again on fruit flies and on brain organoids, lentil-sized clusters of human brain cells grown from stem cells. According to the film, those results aren't in yet.

If the isotope difference holds up, it would be hard to explain without quantum physics. If it doesn't, one of the best clues for the quantum camp goes away. Either result is useful, which is what makes it a good experiment.

The far end of the idea

Neven's group has also described a much more speculative step: linking a quantum computer first to an organoid and, one day, to a person's brain, to see whether the person reports a richer experience. Nobody is close to doing this. We mention it because it shows how far the question has moved. The proposal appeared in the peer-reviewed journal Entropy in 2024, and even its authors describe the idea as a conjecture.

What this doesn't mean

None of this shows that your thoughts shape the universe, that "quantum" explains intuition, or that any product can tune your mind. The physicist John Wheeler did argue that observers take part in how reality becomes definite, and some researchers take that seriously. It is still an interpretation of quantum mechanics, not a result. Most neuroscientists think consciousness comes from ordinary brain activity, and they may well be right.

So our hoodie isn't a physics claim. It's about where you put your attention.

Why we're writing about it

Because the one thing each of us knows for certain is that we are experiencing something right now, and science still can't say why. That deserves more attention than most of what's on a phone. Somewhere a lab is filling a chamber with a rare gas to find out what experience is made of. Meanwhile you have a working one of your own, in full color. Look up and use it.

We make clothes, not medical or scientific advice. This article summarizes published research and reporting as of October 2026, and the experiments it describes are ongoing.

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