Schrödinger cat states are a quantum physics phenomenon in which a quantum object exists in two states simultaneously. Schrödinger’s thought experiment imagined a cat being both alive and dead simultaneously.
In actual experiments, this has been observed in the positions of atoms and molecules and the vibrations of electromagnetic resonators. These states were typically created by cooling the quantum object to its lowest energy level, known as the ground state.
Now, researchers led by Gerhard Kirchmair and Oriol Romero-Isart have demonstrated for the first time that it is indeed possible to create quantum superpositions from thermally excited states. The research team has successfully created so-called hot Schrödinger cat states in a superconducting microwave resonator.
Researchers used a transmon qubit in a microwave resonator to generate the cat states. They successfully created the quantum superpositions at temperatures of up to 1.8 Kelvin – which is sixty times hotter than the ambient temperature in the cavity.
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The results show that generating highly mixed quantum states with distinct properties is possible.
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 system’s ground state. It turned out that adapted protocols also work at higher temperatures, generating distinct quantum interferences.
This opens up new opportunities for creating and using quantum superpositions, for example, in nanomechanical oscillators, for which achieving the ground state can be technically challenging.
Temperature is believed to destroy quantum effects. The measurements confirm that quantum interference can persist even at high temperatures.
These research findings could benefit the development of quantum technologies. The work reveals that it is possible to observe and use quantum phenomena even in less ideal, warmer environments.
Journal Reference:
- Ian Yang, Thomas Agrenius, Vasilisa Usova, Oriol Romero-Isart, Gerhard Kirchmair. Hot Schrödinger Cat States. Science Advances 2025 DOI: 10.1126/sciadv.adr4492
Source: Tech Explorist
