DoLed
Quantum Computing: QuBit state from a multi-QuBit register (page 99)
the statement “The quantum state of a qubit is obtained by reading across a row … |0011>” seems quite problematic to me.
First, the quantum (pure) state of the considered qubit is a priori not well defined any more at this stage, the global state of the 7-qubits register must be considered as a whole because of entanglement (see next chapter)
Second, even if we could assign this qubit a well defined quantum state, using the notation “0011>” for it is very misleading, as this is used also for the tensor product of qubit states…
First Post!
nihal.mehta
Hi Dominique,
All that the statement you referenced is saying is that the quantum state of the first qubit, q[0], is in a superposition of 4 states: |0>, |0>, |1>, |1>. This is simply abbreviated for ease of reading to |0011>.
You are right that that the entire state must be considered as a whole. This is precisely the mega-qubit.
Hope this helps.
Regards,
Nihal
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