Posted on 04/04/2025 6:53:04 PM PDT by Red Badger
Quantum scientists have shown it’s possible to generate Schrödinger cat states in warmer conditions, challenging the assumption that cold is essential for quantum effects. Credit: SciTechDaily.com
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Researchers have pulled off a quantum feat that defies traditional expectations—they’ve created Schrödinger cat states not from ultra-cold ground states, but from warm, thermally excited ones.
Using a superconducting qubit setup, the team demonstrated that quantum superpositions can exist even at higher temperatures, overturning the long-held belief that heat destroys quantum effects. This breakthrough not only validates Schrödinger’s original “hot cat” concept but also paves the way for more practical and accessible quantum technologies.
Schrödinger’s Cat and Hot Quantum States
Schrödinger cat states are a remarkable feature of quantum physics, where a quantum system can exist in two opposing states at once. The concept comes from Erwin Schrödinger’s famous thought experiment, in which a cat is imagined to be both alive and dead simultaneously. In real-world experiments, similar quantum superpositions have been observed—not with actual cats, but in things like the positions of atoms and molecules, or the vibrations of electromagnetic resonators.
Until now, these kinds of superpositions were typically created by first cooling the quantum system to its ground state, its lowest possible energy level. But in a new breakthrough, researchers led by Gerhard Kirchmair and Oriol Romero-Isart have shown it’s possible to create Schrödinger cat states even when the system starts out thermally excited, or “hot.”
“Schrödinger also assumed a living, i.e. ‘hot’ cat in his thought experiment,” remarks Gerhard Kirchmair from the Department of Experimental Physics at the University of Innsbruck and the Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (ÖAW). “We wanted to know whether these quantum effects can also be generated if we don’t start from the ‘cold’ ground state,” says Kirchmair.
In Erwin Schrödinger’s thought experiment, it is a cat that is alive and dead at the same time. Credit: University of Innsbruck/Harald Ritsch
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Creating Quantum Superpositions at Higher Temperatures
In their study, published today (April 4) in Science Advances, the team used a transmon qubit inside a microwave resonator to create the cat states. Remarkably, they succeeded at temperatures up to 1.8 Kelvin, around 60 times hotter than the resonator’s usual environment.
“Our results show that it is possible to generate highly mixed quantum states with distinct quantum properties,” explains Ian Yang, who performed the experiments reported in the study.
Adapting Protocols to Generate Hot Cat States
The researchers used two special protocols to create the hot Schrödinger cat states. These protocols were previously used to produce cat states starting from the ground state of the system. “It turned out that adapted protocols also work at higher temperatures, generating distinct quantum interferences,” says Oriol Romero-Isart, until recently Professor of Theoretical Physics at the University of Innsbruck and research group leader at IQOQI Innsbruck and since 2024 Director of ICFO – the Institute of Photonic Sciences in Barcelona.
“This opens up new opportunities for the creation and use of quantum superpositions, for example in nanomechanical oscillators, for which achieving the ground state can be technically challenging.”
Researchers generated highly mixed quantum states with distinct quantum properties. Credit: IQQOI Innsbruck
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Defying Expectations About Temperature and Quantum Interference
“Many of our colleagues were surprised when we first told them about our results, because we usually think of temperature as something that destroys quantum effects,” adds Thomas Agrenius, who helped develop the theoretical understanding of the experiment. “Our measurements confirm that quantum interference can persist even at high temperature.”
Implications for Future Quantum Technologies
These research findings could benefit the development of quantum technologies. “Our work reveals that it is possible to observe and use quantum phenomena even in less ideal, warmer environments,” emphasizes Gerhard Kirchmair. “If we can create the necessary interactions in a system, the temperature ultimately doesn’t matter.”
Reference:
“Hot Schrödinger Cat States”
by Ian Yang, Thomas Agrenius, Vasilisa Usova, Oriol Romero-Isart, Gerhard Kirchmair, 4 April 2025, Science Advances.
DOI: 10.1126/sciadv.adr4492
The study was funded by the Austrian Research Fund FWF and the European Union, among others.
Hot Cat Ping!...........................
Somebody put a bowl of water on that tin roof
Just close your eyes and count the particles floating on the Atlantic.
Sure; as soon as I give my cat his treat.
All the talk and writing about Schrödinger’s equation and/or his mythical cat...
Enough!
Where are his home video tapes of the days & nights he was shacked up with all those women during which he came up with all this stuff...
Can Alive, Dead and Hot Cat be one of our Viking Kitties?
Was the cat on a hot tin roof?
I am so stealing that graphic!
Schrödinger just didn’t want to clean the cat box.
“There might be a live cat in there. There might be a dead cat in there. There might be a cat turd in there. One of you students clean the box. “
There's a recently revealed CIA file about how The Cat went into secret exile in South America... /rimshot
Don't they believe in their own beliefs?
WYSIWYG!
Collapse of the grave function..
The grave accent is a diacritical mark used to varying degrees in French, Dutch, Portuguese, Italian, Catalan...>>>
It has no single meaning, but can indicate pitch, stress, or other features.
These folks really need to think outside the box to learn how to live a little.
They have new data that wasn’t available before this. They don’t have beliefs, that’s just the writer’s term.
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