PAPER Informational approach to the quantum symmetrization postulate

A remarkable feature of quantum theory is that particles with identical intrinsic propertiesmust be treated as indistinguishable if the theory is to give valid predictions in all cases. In the quantum formal-ism, indistinguishability is expressed via the symmetrization postulate (Dirac P 1926Proc. R. Soc.A 112 661,HeisenbergW1926Z. Phys. 38 411), which restricts a systemof identical particles to the set of symmetric states (‘bosons’) or the set of antisymmetric states (‘fermions’). However, the physical basis and range of validity of the symmetrization postulate has not been established. Awell-known topolo-gical derivation of the postulate implies that its validity depends on the dimensionality of the space in which the particlesmove (LaidlawMandDeWitt C 1971 Phys. Rev.D 3 1375–8, Leinaas JM and Myrheim J 1977 Il NuovoCimentoB 37 1–23).Herewe show that the symmetrization postulate can be derived by strictly adhering to the informational requirement that particles which cannot be experi-mentally distinguished fromone another are not labelled. Our key novel postulate is the operational indistinguishability postulate,which posits that the amplitude of a process involving several indis-tinguishable particles is determined by the amplitudes of all possible transitions of these particles when treated as distinguishable. The symmetrization postulate follows by requiring consistencywit