On Purported Physical Realizations of So-called Quantum Information Technologies

Abstract

Bell’s inequality is derived by resorting to a hidden-variable theory devised for resolving the Einstein-Bohr debate on the conceptual foundations of quantum mechanics. The legitimacy of quantum superposition for describing the physical world is the essence of the debate. Einstein argued against the legitimacy of quantum superposition. Testing Bell’s inequality by experiments with the experimental result explained by Bell’s theorem opened the door to so-called quantum information technologies. In quantum information theory, “quantum bit” (or “qubit” for short) in a form of quantum superposition is supposed to carry quantum information. In the present paper, a new principle, the general principle of measurements, has been proved as a mathematical theorem. Based on this principle, the experiment for testing Bell’s inequality and so-called experimental evidence for physically realizable “qubit” have been scrutinized. The findings are as follows. Although most physicists believe that Einstein’s vision of the physical world contradicts the experimental result of testing Bell’s inequality, neither the experimental result nor Bell’s theorem is relevant to Einstein’s viewpoint, because Bell’s inequality failed to capture the essence of the Einstein-Bohr debate. The experimental result and the measurement outcomes of various experiments involving “qubit” are all erroneously explained. Quantum mechanics can be completed by using disjunction (“or”) as the logical relation between the orthonormal vectors that span an arbitrarily given Hilbert space without resorting to any hidden-variable theory, while the mathematical setting will remain essentially unchanged. All kinds of “qubit” violate the general principle of measurements and can only describe imaginary objects that do not exist in the real world. A very regrettable conclusion from the above findings is inevitable: All quantum information technologies are not physically realizable, because quantum information has no physical carriers.