Researchers at the University of Oxford have created a new type of quantum superposition, a phenomenon often associated with the famous Schrödinger's cat thought experiment. Unlike previous versions, these newly demonstrated states are built from highly nonclassical quantum components. The achievement could help advance quantum computing beyond traditional binary systems, improve sensing technologies, and provide new insights into the foundations of quantum physics.
One of the most surprising features of quantum mechanics is that objects can exist in multiple states simultaneously. This concept is commonly illustrated by Schrödinger's cat, a hypothetical cat that is considered both alive and dead until it is observed.
While the thought experiment is fictional, scientists routinely create real quantum superpositions in the laboratory. Atoms, light, and even motion can be placed into multiple quantum states at once. The ability to generate and control these states is critical for technologies such as quantum computers and ultra-precise clocks.
A familiar example is a quantum bit, or qubit, which can exist in a combination of both 0 and 1 at the same time. Ancak, quantum systems are capable of much more than two-state behavior.
Quantum harmonic oscillators, which can occupy many energy levels, offer a far richer set of possibilities. These oscillators describe a wide range of physical systems, including light, vibrations, and the motion of trapped particles. Scientists have used them to create many different kinds of quantum superpositions. One well-known example is the "cat state," where an oscillator exists as a superposition of two wave packets moving in opposite directions. These wave packets, called coherent states, are the closest quantum equivalents to classical motion.
Building Quantum States From Nonclassical Components
The Oxford team has now demonstrated an entirely new family of quantum superpositions.
Reconstructed Wigner function of a superposition of two trisqueezed states. Its sixfold rotational symmetry and regions of Wigner negativity reveal highly non-classical quantum interference in the ion's motion. Credit: Department of Physics, University of Oxford
