Überlagerungszustand

Überlagerungszustand, often translated as superposition state, is a fundamental concept in quantum mechanics. It describes a phenomenon where a quantum system can exist in multiple possible states simultaneously until a measurement is performed. Before measurement, the system is not in any single definite state but rather in a combination of all potential states.

This idea is famously illustrated by Schrödinger's cat thought experiment. In this scenario, a cat placed in a box with a radioactive atom and a poison vial is considered to be both alive and dead at the same time until the box is opened and the cat's state is observed. The act of observation or measurement collapses the superposition, forcing the system into one of its possible definite states.

Mathematically, an Überlagerungszustand is represented as a linear combination of basis states. For instance, if a quantum bit, or qubit, can be in state |0⟩ or state |1⟩, a superposition state can be written as α|0⟩ + β|1⟩, where α and β are complex numbers representing the probability amplitudes of each state. The square of the magnitude of these amplitudes, |α|² and |β|², gives the probability of measuring the qubit in state |0⟩ or |1⟩, respectively.

The principle of superposition is crucial for understanding many quantum phenomena, including quantum computing, where qubits in superposition can perform calculations far more efficiently than classical bits. It is a key departure from classical physics, where an object must always be in a single, well-defined state.