11.1 Time Evolution
Consider again the description of the dynamics of quantum mechanical systems, briefly covered in Chapter 1 (as one of the postulates of quantum mechanics) and Chapter 2 (where we introduced the principles of Adiabatic Quantum Computing). These dynamics are governed by the Schrödinger equation (1.2.2):
with some initial condition , where
is the quantum state at time t and H is the time-independent Hamiltonian. Its solution is given by (1.2.2), namely
where the operator U(0,t) is obtained from the Hamiltonian H by (1.2.2):
We work with units where ℏ is set to 1, so that the system dynamics reads
If the initial state of the system is known, then the state of the system at time t is also known and is determined by the action of the Hamiltonian H over the period of time t.
However, the solution (11.1) assumes that the...