Ok, I've tried separating one of the qubits from the rest to obtain a product state and succeded for the second one (B):
##|\psi\rangle = \frac{1}{2}(|0\rangle_B + i|1\rangle_B)(|00\rangle_{AC} + i|11\rangle_{AC})##,
so it seams that qubit A is entangled with C (the first and the third)...
Homework Statement
Determine which qubits are entangled:
##|\psi\rangle=\frac{1}{2}(|000\rangle+i|010\rangle+i|101\rangle-|111\rangle)##
Homework EquationsThe Attempt at a Solution
[/B]
My idea was to first calculate the density operator
##\rho = |\psi\rangle \langle\psi|##
and then find...
Homework Statement
I have the following task:
In quantum free scalar field theory find commutators of creation and anihilation operators with total four-momentum operator, starting with commutators for fields and canonical momenta. Show that vacuum energy is zero.
Homework Equations...