ZME Science
No Result
View All Result
ZME Science
No Result
View All Result
ZME Science

Home → Science → News

This crystal is world’s largest Schrödinger’s cat

Superposition shouldn't be possible for objects larger than an atom -- but these scientists are defying conventional wisdom.

Tibi PuiubyTibi Puiu
April 27, 2023
in News, Physics
A A
Edited and reviewed by Zoe Gordon
Share on FacebookShare on TwitterSubmit to Reddit
three cats and three skeletons that illustrate schroedinger's experiment.
Credit: ETH Zurich.

You’ve probably heard about the famous thought experiment that involves Schrödinger’s cat, which can be both alive and dead at the same time. Although it sounds like nonsense in everyday life, scientists have been able to explore analogous situations in the laboratory by using atoms or molecules in quantum mechanical superposition states of being in two places at the same time.

Superposition is only possible in the microcosmos for more quantum objects, such as electrons. Or so we thought.

In a new study, a team of researchers led by Yiwen Chu, a professor at the Laboratory for Solid State Physics at ETH Zurich, has created the heaviest Schrödinger’s cat yet by putting a small crystal into a superposition of two oscillation states.

Creating a Schrödinger Cat

In the original thought experiment, Austrian quantum physicist Edwin Schrödinger imagined a cat locked inside a metal box with a radioactive substance, a Geiger counter, and a flask of poison.

The atom in the substance may or may not decay through a quantum mechanical process with a certain probability, and the decay products might cause the Geiger counter to go off and trigger a mechanism that smashes the flask containing the poison, which would eventually kill the cat.

In this situation, according to the Copenhagen interpretation, developed in the Danish city by luminaries of quantum theory, Niels Bohr and Werner Heisenberg, the atom, and hence the cat whose faith is tied to it, are in a superposition of being decayed/dead and not decayed/alive.

Schrödinger’s thought experiment was actually devised to mock the Copenhagen interpretation, showing how quantum mechanics had been absurdly interpreted. He never contemplated the alive/dead cat superposition seriously.

RelatedPosts

This edible QR code tag can detect fake whiskey and medicines
Engineering microorganisms for future generations
This hand-woven computer sent astronauts to the Moon
Photo project reveals deep bond between the homeless and their pets

Nevertheless, since his time, the cat thought experiment and the notion that quantum superpositions of macroscopic states could be possible have led to the Many-Worlds interpretation of quantum theory.

But is a macroscopic superposition really impossible?

Chu and colleagues decided to put this idea to the test. No worries, no feline was hurt in the process. Instead, they probed this question by creating a so-called “cat state” using an oscillating crystal, which is supposed to represent the cat, and a superconducting circuit representing the original decaying atom.

Weighing the Fattest Quantum Cat

schematic of a schroedinger's cat experiment
In the ETH Zurich experiment, the cat is represented by oscillations in a crystal (top and blow-up on the left), whereas the decaying atom is emulated by a superconducting circuit (bottom) coupled to the crystal. Credit: ETH Zurich

The superconducting circuit can take on the logical states “0” or “1” or a superposition of both states, “0+1”. This circuit is essentially a “qubit”, or a quantum bit.

A layer of piezoelectric material creates an electric field when the crystal changes shape while oscillating, and that electric field can be coupled to the electric field of the qubit. Hence, the superposition state of the qubit can be transferred to the crystal. As a result, the crystal can now oscillate in two directions at the same time—up/down and down/up, for instance. Those two directions represent the “alive” or “dead” states of the cat.

By putting the two oscillation states of the crystal in a superposition, Chu’s team has effectively created a Schrödinger cat weighing 16 micrograms, which is roughly the mass of a fine grain of sand but nowhere near that of a cat. Nevertheless, it is several billion times heavier than an atom or molecule, making it the fattest quantum cat to date.

Why This Matters

Quantum mechanics is the physics of the small: the theory governs the behavior of atoms and particles on microscopic scales. Yet, scientists have long puzzled over why these rules seemingly do not apply to the macroscopic world we experience.

Objects at the macro scale follow the laws of classical physics, which describe how everyday things move and behave. The question remains: where does the transition from the quantum to the classical occur?

The answer to this fundamental question is not only of academic interest, but also of practical relevance. One of the potential applications of quantum physics is quantum computing, which could in principle solve certain problems much faster than classical computers.

One of the biggest challenges in developing quantum computers is to create and maintain a state of quantum superposition in a large number of qubits, which are the building blocks of quantum computers. In a Schrödinger’s cat state, the information in the qubit is distributed over a macroscopic object. This could help to overcome some of the challenges of maintaining quantum coherence in large systems.

The research has several implications for the future. First, the creation of more robust quantum bits. Second, the findings help scientists better understand the mystery of why quantum superpositions are not observed in the macroscopic world. With the latter point in mind, Chu’s team hopes to push the mass limits of her crystal cats even further in the future.

In addition, this research may lead to measuring small disturbances, which are difficult to detect using conventional methods. According to Chu, “One potential application could be the detection of very weak electric or magnetic fields.”

The oscillations in the crystal can be disturbed by an external field, and this change can be measured by the superconducting qubit. By detecting the change in the superposition state of the cat, the external field can be measured. This can be useful in detecting tiny changes in magnetic fields, which can be applied in medical imaging or quantum communication.

The work of Chu and her colleagues marks an important step towards realizing the elusive Schrödinger’s cat state in a macroscopic object. While a real cat may never be in such a state, the experiment provides insight into the puzzling boundary between the quantum and classical worlds and could pave the way towards new technologies.

The findings appeared in the journal Science.

ShareTweetShare
Tibi Puiu

Tibi Puiu

Tibi is a science journalist and co-founder of ZME Science. He writes mainly about emerging tech, physics, climate, and space. In his spare time, Tibi likes to make weird music on his computer and groom felines. He has a B.Sc in mechanical engineering and an M.Sc in renewable energy systems.

Related Posts

Invertebrates

The Worm That Outsourced Locomotion to Its (Many) Butts

byMihai Andrei
4 hours ago
History

The unusual world of Roman Collegia — or how to start a company in Ancient Rome

byMihai Andrei
5 hours ago
Merton College, University of Oxford. Located in Oxford, Oxfordshire, England, UK. Original public domain image from Wikimedia Commons
Bizarre Stories

For over 500 years, Oxford graduates pledged to hate Henry Symeonis. So, who is he?

byMihai Andrei
6 hours ago
News

The Strongest Solar Storm Ever Was 500 Times More Powerful Than Anything We’ve Seen in Modern Times. It Left Its Mark in a 14,000-Year-Old Tree

byTibi Puiu
6 hours ago

Recent news

The Worm That Outsourced Locomotion to Its (Many) Butts

May 16, 2025

The unusual world of Roman Collegia — or how to start a company in Ancient Rome

May 16, 2025
Merton College, University of Oxford. Located in Oxford, Oxfordshire, England, UK. Original public domain image from Wikimedia Commons

For over 500 years, Oxford graduates pledged to hate Henry Symeonis. So, who is he?

May 16, 2025
  • About
  • Advertise
  • Editorial Policy
  • Privacy Policy and Terms of Use
  • How we review products
  • Contact

© 2007-2025 ZME Science - Not exactly rocket science. All Rights Reserved.

No Result
View All Result
  • Science News
  • Environment
  • Health
  • Space
  • Future
  • Features
    • Natural Sciences
    • Physics
      • Matter and Energy
      • Quantum Mechanics
      • Thermodynamics
    • Chemistry
      • Periodic Table
      • Applied Chemistry
      • Materials
      • Physical Chemistry
    • Biology
      • Anatomy
      • Biochemistry
      • Ecology
      • Genetics
      • Microbiology
      • Plants and Fungi
    • Geology and Paleontology
      • Planet Earth
      • Earth Dynamics
      • Rocks and Minerals
      • Volcanoes
      • Dinosaurs
      • Fossils
    • Animals
      • Mammals
      • Birds
      • Fish
      • Amphibians
      • Reptiles
      • Invertebrates
      • Pets
      • Conservation
      • Animal facts
    • Climate and Weather
      • Climate change
      • Weather and atmosphere
    • Health
      • Drugs
      • Diseases and Conditions
      • Human Body
      • Mind and Brain
      • Food and Nutrition
      • Wellness
    • History and Humanities
      • Anthropology
      • Archaeology
      • History
      • Economics
      • People
      • Sociology
    • Space & Astronomy
      • The Solar System
      • Sun
      • The Moon
      • Planets
      • Asteroids, meteors & comets
      • Astronomy
      • Astrophysics
      • Cosmology
      • Exoplanets & Alien Life
      • Spaceflight and Exploration
    • Technology
      • Computer Science & IT
      • Engineering
      • Inventions
      • Sustainability
      • Renewable Energy
      • Green Living
    • Culture
    • Resources
  • Videos
  • Reviews
  • About Us
    • About
    • The Team
    • Advertise
    • Contribute
    • Editorial policy
    • Privacy Policy
    • Contact

© 2007-2025 ZME Science - Not exactly rocket science. All Rights Reserved.