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.
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.”
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 and 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.
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6 Comments
Note 2504061354_Source1. Analyzing【
_According to the domain (*) of my example 1.sms.oms.vix.ain theory, high temperatures are narrow and cold temperatures are wide. Even in narrow areas, vix.ain is the ultra-high temperature core of the universe that operates as os4. Uh-huh.
There is a black hole and a neutron star, a vixer. Thus, a microgravity quantum field is formed even in a narrow space. 2. Temperature is not a requirement for quantum effects because oms4 exists. Huh.
This gives implications for future quantum technologies.
3-1.) We show that superconductor quantum phenomena can be observed and used even in room temperature environments. Ultimately, temperature does not matter if the system can produce the necessary interactions.
View 1.
sample 1.vix.a’6//vixx.a(b1,g3,k3,o5,n6)
b0acfd|~ |0000e0
000ac0|~|f00bde
0c0fab|~ |000e0d
e00d0c|~|0b0fa0
f000e0|~ |b0dac0
d0f000|~ |cae0b0
0b000f|~ |0ead0c
0deb00|~|ac000f
ced0ba|~|00f000
a0b00e|~|0dc0f0
0ace00|~|df000b
0f00d0|~|e0bc0a
View 2.
02000000
00000101
00010001
00010100
≈≈≈=========
Source 1.
https://scitechdaily.com/alive-dead-and-hot-schrodingers-cat-defies-the-rules-of-quantum-physics/
1.
Alive, dead, and hot: Schrödinger’s cat breaks the rules of quantum physics
Quantum scientists have shown that Schrödinger cat states can be produced under warmer conditions, challenging the assumption that cold is essential for quantum effects.
1-1.
The researchers showed quantum technology that exceeded existing expectations. They created the Schrödinger cat state in a warm and thermally excited state, not in an ultra-cold ground state.
Using a superconducting qubit setting, the team demonstrated that quantum superposition can exist at higher temperatures, reversing a long-standing belief that heat destroys quantum effects. This groundbreaking discovery not only validates Schrödinger’s original “hotcat” concept, but also paves the way for more practical and accessible quantum techniques.
1-1. Schrödinger’s cat and hot quantum state
The Schrödinger cat state is a remarkable feature of quantum physics, in which quantum systems can exist in two opposite states simultaneously. The concept was derived from Erwin Schrödinger’s famous thought experiment, in which one imagines that cats are both alive and dead at the same time. A similar quantum superposition was observed in real experiments. It was observed not in real cats, but in things like the positions of atoms and molecules, or the vibrations of electromagnetic resonators.
So far, this kind of superposition has generally been created by first cooling a quantum system to a ground state, or the lowest possible energy level. But in the new breakthrough, researchers have shown that the system can produce a Schrödinger cat state even if it starts with a thermally excited state, or “hot” state.
2.
Schrödinger also hypothesized a live, or ‘hot’ cat, in his thought experiment. We wanted to see if these quantum effects could be produced even if we didn’t start with a ‘cold’ ground state.
In Erwin Schrödinger’s thought experiment, it is simultaneously a living and dead cat.
2-1. Create quantum overlap at higher temperatures
In a study published today (April 4), the team generated the cat state using transmon qubits inside microwave resonators. Surprisingly, they succeeded at temperatures up to 1.8 Kelvin, which is about 60 times hotter than the resonator’s normal environment.
The results show that it is possible to generate highly mixed quantum states with different quantum properties.
2-2.Tuning Protocols to Create Hotcat Status
Researchers used two special protocols to generate hot Schrödinger cat states. This protocol was previously used to generate cat states, starting from the default state of the system.
2-3.
The recently adapted protocol works even at higher temperatures, producing distinct quantum interference. This opens new opportunities for the creation and use of quantum superposition, for example in nanomechanical oscillators, where achieving the ground state can be technically challenging. Researchers have generated highly mixed quantum states with distinct quantum properties.
3.
to challenge the expectations of temperature and quantum interference
Many of our colleagues were surprised when we first said the result. Because we usually think of temperature as destroying the quantum effect. Our measurements confirmed that quantum interference can persist at high temperatures.
3-1. Implications for Future Quantum Technologies
These findings could be helpful in the development of quantum techniques. Research shows that quantum phenomena can be observed and used in less ideal and warmer environments. Ultimately, temperature doesn’t matter if the system can produce the necessary interactions.
Some people would rather believe in an ugly cat than believe in the spin of topological vortices.
What a pitiful group of children.
Ask the researchers:
Is this the pride of the Physics Review series of publications, or the sadness of some so-called researchers?
So Schrodinger’s cat is on heat?
Quantum superposition is nonsense. In the future it’ll all be written off as we just didn’t have clue one how it all works.
That’s ridiculous
Hot Dog, I mean Cat.