In quantum mechanics, a superposition is a fundamental concept that describes the state of a quantum system when it exists in multiple states simultaneously. The "real" state of a particle in a superposition is a complex mathematical combination of these individual states, known as quantum states or wavefunctions.
According to the principles of quantum mechanics, before a measurement is made, a particle can be in a superposition of different states, each with an associated probability amplitude. These probability amplitudes determine the likelihood of observing the particle in a particular state when a measurement is performed.
However, when a measurement is made, the superposition "collapses" into one of the possible states, and the observer obtains a definite outcome. The specific state observed is random, but its probability is related to the amplitudes of the individual states in the superposition. This phenomenon is known as wavefunction collapse or the measurement problem in quantum mechanics.
The nature of superposition and wavefunction collapse is still a topic of ongoing debate and interpretation in the field of quantum mechanics. Various interpretations, such as the Copenhagen interpretation, the many-worlds interpretation, or the consistent histories interpretation, propose different explanations for the nature of superposition and the outcome of measurements.
In summary, the "real" state of a particle in a superposition is a mathematical combination of different states, but when a measurement is made, the outcome is probabilistic, and the particle is observed in a single state.