New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Schrödinger's cat

Schrödinger's cat is a seemingly paradoxical thought experiment devised by Erwin Schrödinger that attempts to illustrate the incompleteness of an early interpretation of quantum mechanics when going from subatomic to macroscopic systems. Schrödinger proposed his "cat" after debates with Albert Einstein over the Copenhagen interpretation, which Schrödinger defended, stating in essence that if a scenario existed where a cat could be so isolated from external interference (decoherence), the state of the cat can only be known as a superposition (combination) of possible rest states (eigenstates), because finding out (measuring the state) cannot be done without the observer interfering with the experiment — the measurement system (the observer) is entangled with the experiment.

The thought experiment serves to illustrate the strangeness of quantum mechanics and the mathematics necessary to describe quantum states. The idea of a particle existing in a superposition of possible states, while a fact of quantum mechanics, is a concept that does not scale to large systems (like cats), which are not indeterminably probabilistic in nature. Philosophically, these positions which emphasize either probability or determined outcomes are called (respectively) positivism and determinism.

Related Stories
 


Matter & Energy News

September 28, 2026

Scientists recreated a particle-forming process linked to the extreme physics of the early universe using a 13-ion quantum simulator. The breakthrough suggests quantum computers could eventually help researchers investigate how matter formed and ...
CERN has started replacing some of the Large Hadron Collider’s most important magnets as part of its High-Luminosity upgrade. The new superconducting magnets will produce fields about 40% stronger, allowing particle beams to be squeezed more ...
Researchers have shown that exotic quantum particles called non-Abelian anyons can perform the full range of operations needed for universal quantum computing. Using 54 qubits on Quantinuum’s H2 processor, they combined braiding and fusion to ...
Researchers have shown that multiple time crystals inside a semiconductor can synchronize their oscillations, much like pendulum clocks gradually falling into the same rhythm. The coupling is carried by spin-polarized electrons, allowing time ...
Stanford researchers have recorded the first real-time quantum jumps of sound, watching single phonons abruptly vanish from one energy state to another. The breakthrough could open new paths for quantum computing, error correction, highly sensitive ...
Scientists at Oak Ridge National Laboratory have developed a surprisingly simple way to turn polyethylene, the common plastic used in shopping bags and cutting boards, into gasoline and diesel-like fuels. The process uses inexpensive aluminum-based ...
Scientists have developed ultra-bright nanoparticles that can detect tiny amounts of chemicals and distinguish between molecules that look almost identical. The technology could one day provide a cheaper way to catch dangerous drug impurities or ...
A deep-sea microbe uses an exceptionally heat-resistant enzyme to turn atmospheric nitrogen into ammonia at temperatures that would destroy most proteins. Its unusual structure and a newly observed reaction state may reveal an ancient, shared ...
Complex systems may work better when their parts are not perfectly alike. Northwestern physicists found that carefully balanced variation, or “disorder,” can make networks such as power grids, ecosystems, neurons, and materials more stable. Even ...
Scientists are looking to diatoms, sea sponges, and plants for a cleaner way to recover rare earth elements and other valuable minerals hidden inside coal ash, red mud, and mine tailings. The bio-inspired approach could turn massive industrial waste ...
A new Caltech device can redirect a beam of light in just 74 femtoseconds using another beam and a nanoscale silicon metasurface. The breakthrough could pave the way for dramatically faster photonic communications, computing, and sensing ...
A pocket-sized, roughly $100 detector can reveal the invisible stream of cosmic particles constantly passing through Earth and even through our bodies. What began as a student physics project is now being used in major experiments, balloon missions, ...

Latest Headlines

updated 12:56 pm ET