it was solved by giving up the assumption of local realism, but other interpretations have also emerged. For more information see the Bell test experiments. The no-communication theorem proves that this phenomenon cannot be used for faster-than-light communication of classical information. Measurement on registers with pairwise entangled qubits Take a register A with qubits all initialized to and feed it through a parallel Hadamard gate Register A will then enter the state that have equal probability of when measured to be in any of its possible states; to Take a second register B, also with qubits initialized to and pairwise CNOT its qubits with the qubits in register A, such that for each the qubits and forms the state If we now measure the qubits in register A, then register B will be found to contain the same value as A. If we however instead apply a quantum logic gate on A and then measure, then where is the unitary inverse of . Because of how unitary inverses of gates act, For example, say , then The equality will hold no matter in which order measurement is performed (on the registers A or B), assuming that has run to completion. Measurement can even be randomly and concurrently interleaved qubit by qubit, since the measurements assignment of one qubit will limit the possible value-space from the other entangled qubits. Even though the equalities holds, the probabilities for measuring the possible outcomes may change as a result of applying , as may be the intent in a quantum search algorithm. This effect of value-sharing via entanglement is used in Shor's algorithm, phase estimation and in quantum counting. Using the Fourier transform to amplify the probability amplitudes of the solution states for some problem is a generic method known as "Fourier fishing". Logic function synthesis Functions and routines that only use gates can themselves be described as matrices, just like the smaller gates. The matrix that represents a quantum function acting on qubits has size For example, a function that acts on a "qubyte" (a register of 8 qubits) would be represented by a matrix with elements. Unitary transformations that are not in the set of gates natively available at the quantum computer (the primitive gates) can be synthesised, or approximated, by combining the available primitive gates in a circuit. One way to do this is to factor the matrix that encodes the