In an exciting new experiment, scientists in Innsbruck, Austria, have managed to create mysterious quantum states—known as Schrödinger cat states—without needing extremely cold conditions.
This discovery challenges a long-standing belief in physics: that quantum effects only happen in perfectly cold, quiet environments.
Schrödinger’s cat is a famous thought experiment in quantum physics.
It describes a cat that is both alive and dead at the same time until someone opens the box to check.
Of course, real cats don’t behave this way, but in the quantum world, particles and systems can exist in two opposite states at once.
These strange combinations are called “superpositions.”
Until now, scientists could only create these Schrödinger cat states by first cooling things down to almost absolute zero, the coldest possible temperature. That’s because heat usually destroys delicate quantum behavior.
But the team in Innsbruck, led by physicists Gerhard Kirchmair and Oriol Romero-Isart, has shown that it’s possible to create quantum superpositions even when the system starts off warm. They used a tiny device called a transmon qubit, placed inside a microwave resonator, to do this.
Surprisingly, they were able to generate Schrödinger cat states at temperatures as high as 1.8 Kelvin. That’s still very cold—around -271 degrees Celsius—but it’s about 60 times warmer than what scientists usually use in such experiments.
“We wanted to see if quantum effects can still appear when we don’t start with the coldest possible conditions,” said Kirchmair. “After all, Schrödinger imagined a living cat—not a frozen one!”
The researchers used two special methods, originally designed for cold systems, and adjusted them to work in warmer conditions.
The results showed that even “hot” quantum states—those full of random energy from heat—can still show clear signs of quantum interference, a key sign of superposition.
“Our colleagues were quite surprised,” said Thomas Agrenius, one of the team members. “Most people assume that temperature always destroys quantum effects. But our measurements prove that these strange effects can survive even when things aren’t perfectly cold.”
This finding could be a big step forward for developing quantum technologies. Many promising devices, like tiny vibrating mechanical systems, are difficult to cool down to the ground state. Being able to create and use quantum states without needing extreme cold makes these devices more practical in the future.
As Kirchmair put it, “If we can build the right interactions, then the temperature might not matter as much as we thought.”
