16. Measurement and Time Evolution

Question 1

How is the measurement process in QM represented?

Answer 1

By an operator

Question 2

What do measurements do to a quantum state?

Answer 2

They change it

Question 3

Describe how the result of a measurement of a dynamical variable is determined

Answer 3

It is determined probabilistically when the measurement is made - get 1 value from the eigenvalue spectrum

Question 4

What happens to the wavefunction when a measurement is made on it?

Answer 4

It collapses to the eigenfunction of the measurement operator corresponding to a measured eigenvalue

Question 5

What happens to the wavefunction when no measurements are made on it?

Answer 5

It evolves according to the TDSE

Question 6

For the separated TDSE, what does the time evolution, f(t) component represent?

Answer 6

f(t) is the time evolution for each energy eigenstate in the wavefunction
- Could be a linear combination of states with different energies