My notes about the basics of quantum information - part 2
Quantum information
My notes bellow from this lesson on the basics of quantum information , the section about quantum information.
Everything is a bit similar to the way of describing classical information : my notes.
A quantum state of a system is represented by a column vector( quantum vector) with indices corresponding to the classical states.
The differences:
- The elements are complex numbers( e.g. 2+3i)
- The Euclidean norm of such vector is equal to 1.
- The elements are sometimes called amplitudes instead of probabilities*.
Qubit - quantum bit , a bit that can be in a quantum state
Quantum state vectors representing qubit state vectors with classical states 0 and 1.
Measuring quantum system => extracting classical state info
Standard basis measurement => it is a classical state; probability for a given classical state to be the outcome of a measurement is the absolute value squared of the corresponding element of the quantum state vector.
Measuring the system - the quantum system changes, the system become in the the observed classical state as a quantum state.
