Physicists make Schrödinger’s fattest cat ever

Imagine a cat. I assume you fancy a live one. It doesn’t matter. You’re wrong either way – but you’re also right.

This is the precursor to Erwin Schrödinger’s 1935 thought experiment for describing quantum states. Now, researchers have managed to create Schrödinger’s fat (i.e. huge) cat, testing the limits of the quantum realm and where it gives way to the classical. Physics.

Thus, Schrödinger’s experiment is as follows: a cat is in a box with a poison that is released from its packaging if an atom of a radioactive substance, also present in the box, decays. Since it is impossible to know whether or not a substance will decompose in a given time frame, the cat remains alive and dead until the box is opened and some objective truth is determined. (You can read more about the thought experiment here.)

In the same way, particles in quantum states (qubits, if used as bits in a quantum computer) are in a state of quantum superposition (i.e. “alive” and “dead”) until they are measured, at which point the superposition collapses. Unlike ordinary computer bits which have a value of either 0 or 1, qubits can be both 0 and 1 at the same time.

Now, researchers have made Schrödinger’s cat much heavier than previously created ones, and are testing the muddy waters as the world of quantum mechanics gives way to classical physics to the familiar microscopic world. their research published This week in Science.

In place of the virtual cat was a small crystal, placed in a superposition of two states of oscillation. Oscillation states (up or down) are equivalent to the life or death situation in Schrödinger’s thought experiment. A superconducting circle, which is a qubit, was used to represent the atom. The team attached an electric field creating a material to the circuit, allowing its superposition to travel into the crystal. Capish?

“By putting the two states of oscillation in the crystal in superposition, we have effectively created a Schrödinger’s cat weighing 16 micrograms,” said Yuen Zhu, a physicist at ETH Zurich and lead author of the study, one of the universities. launch.

16 micrograms is roughly equivalent to the mass of a grain of sand, and that’s a pretty fat cat at the quantum level. According to the version, it is “billions of times heavier than an atom or a molecule, which makes it the fattest quantum cat to date.”

This isn’t the first time physicists have tested whether quantum behaviors can be observed in classical objects. Last year, a different team They declared that they had entangled tardigradesthough a number of physicists told Gizmodo that claim was poppy.

This is a little different, as the latter team was only testing the mass of an object in a quantum state, not the entanglement potential of a living organism. While this is not in the team’s plans, working with larger groups “will allow us to better understand why quantum effects disappear in the macroscopic world of real cats,” Zhu said.

As for the real boundary between the two worlds? “No one knows,” Matteo Fadel, a physicist at ETH Zurich and co-author of the research paper, wrote in an email to Gizmodo. “That’s the interesting thing, and the reason why showing quantum effects in mass gain systems is so unprecedented.”

The new research takes Schrödinger’s famous thought experiment and gives it some practical applications. Controlling quantum materials in a superposition state can be useful in a number of areas where very precise measurements are required; For example, help Noise reduction in interferometers that measure gravitational waves.

Fadell is currently studying “whether gravity plays a role in decoherence of quantum states, specifically whether it is responsible for the transition from quantum to classical as suggested two decades ago by Penrose.” Gravity does not appear to exist at the subatomic level and is not accounted for in the Standard Model of particle physics.

The quantum world is ripe New discoveriesUnfortunately, it is full UnknownAnd ImpasseAnd Annoying new problems.

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