Quantum states refer to the possible configurations or states that a quantum system can exist in. These states are described by wave functions, which contain information about the probability of the system being in a particular state.
The probability of a quantum state is determined by the square of the amplitude of the corresponding wave function. This is known as the Born rule and is a fundamental principle of quantum mechanics.
In classical mechanics, probabilities are determined by the frequency of events occurring. In quantum mechanics, probabilities are determined by the wave function, which represents the likelihood of finding a particle in a particular state. This means that quantum probabilities can be non-deterministic and allow for superposition of states.
In quantum computing, probabilities of quantum states are used to represent information in quantum bits, or qubits. The superposition of qubits allows for multiple calculations to be performed simultaneously, increasing the speed and efficiency of computing.
No, probabilities of quantum states cannot be directly measured. Instead, they are inferred through measurements of the system, such as the position or momentum of a particle. This is due to the uncertainty principle, which states that the act of measurement can alter the state of the system.