Physicists at the University of Oxford have engineered a new class of ‘cat states’ — quantum superpositions constructed not from ordinary wave packets, but from deeply exotic, nonclassical components — opening unexpected paths toward more resilient quantum computers. “Unlike classical physics, quantum mechanics allows objects to exist in more than one state at the same time,” said University of Oxford’s Dr. Sebastian Saner and his colleagues. “This idea is often illustrated by Schrödinger’s cat, imagined as being both alive and dead until it is observed.” “In a lab, physicists can create less dramatic but very real versions of this effect by placing atoms, light, or motion into two distinct quantum states at once.” “Creating and controlling these superpositions is essential for applications ranging from quantum computing to precision timekeeping.” “A simple example is a quantum bit, or qubit, in a superposition of both 0 and 1. But quantum systems are not limited to just two states.” “In a quantum harmonic oscillator, which can occupy many different energy levels, there is a much richer set of possibilities.” “Quantum harmonic oscillators describe many physical systems, including light, vibrations and the motion of trapped particles, and have been used to create a wide variety of quantum superpositions.” “One well-known example is a cat state, in which an oscillator is placed in a superposition of two wave packets displaced in opposite directions.” “These wave packets, known as coherent states, resemble classical motion as closely as quantum mechanics allows.” In their new research, Dr. Saner and co-authors demonstrated a new family of quantum superpositions. Instead of building cat-like states from coherent-state wave packets, they developed a method for creating superpositions from a broad range of components that are themselves highly nonclassical. In examples such as squeezed-state superpositions, quantum uncertainty is redistributed differently in each part