Physicists Develop Heaviest Schrödinger's Cat Ever

Physicists have successfully crafted the heaviest Schrödinger's cat to date, enabling the peculiar characteristics of the quantum realm to be observed on a larger scale. This achievement involved vibrating a sapphire crystal containing 100 million billion atoms, which led to the creation of the largest quantum superposition ever recorded. Weighing a mere 16 micrograms, the crystal is still trillions of times more massive than molecules of previous large-scale quantum states and can be seen with the naked eye.

Named after Erwin Schrödinger's renowned thought experiment, this groundbreaking Schrödinger's cat crystal may pave the way for more resilient quantum computers and uncover insights into why quantum effects are not experienced in the macroscopic world. The researchers' findings were published in the journal Science on April 20.

Yiwen Chu, the lead author and a physics professor at the Laboratory for Solid State Physics at ETH Zurich, stated that although they could not conduct experiments with a real cat, creating a 16-microgram Schrödinger's cat by superimposing two oscillation states of the crystal was a significant accomplishment.

In Schrödinger's thought experiment, the peculiar principles of the quantum world are illustrated by envisioning a cat placed in a sealed box with a poison vial controlled by radioactive decay, an entirely random quantum process. According to quantum mechanics, the cat exists in a superposition of states, being both dead and alive simultaneously, until the box is opened and the cat is observed.

To achieve this feat, the physicists linked the vibrating part of the sapphire crystal to a superconducting circuit, causing it to vibrate in a superposition of two directions simultaneously. The researchers then measured the spatial separation of the crystal's two vibrating states to verify the creation of a quantum cat. Despite the vibrations being subatomic in scale, they were easily distinguishable from random thermal and quantum vibrations, proving the cat's existence.

In the future, Chu aims to further increase the mass of the Schrödinger's cat crystal, leading to the creation of macroscopic quantum objects that could enhance information storage in quantum computers, detect gravitational waves and dark matter, and uncover how quantum effects vanish at the scale of real-life cats.