What is Tensor Notation

Introduction to Quantum Computing

"Tensor notation" is where a two-qubit state |x>⊗|y> with the first qubit in state |x>, and the second qubit in state |y>. It can drop the ⊗ and write a two-quit state as simply |x>|y> . The resulting output state can no longer separable into two single-qubit components such as (...)x⊗(...)y.

This is known as an entangled state.