In this paper, we show that spin waves, the elementary excitation of the Heisenberg magnetic
system, obey a kind of intermediate statistics with a finite maximum occupation number
n. We construct an operator realization for the intermediate statistics obeyed by magnons,
the quantized spin waves, and then construct a corresponding intermediate-statistics
realization for the angular momentum algebra in terms of the creation and annihilation
operators of the magnons. In other words, instead of the Holstein–Primakoff representation,
a bosonic representation subject to a constraint on the occupation number, we present an
intermediate-statistics representation with no constraints. In this realization, the maximum
occupation number is naturally embodied in the commutation relation of creation and
annihilation operators, while the Holstein–Primakoff representation is a bosonic operator
relation with an additional putting-in-by-hand restriction on the occupation number. We
deduce the intermediate-statistics distribution function for magnons from the
intermediate-statistics commutation relation of the creation and annihilation operators
directly, which is a modified Bose–Einstein distribution. On the basis of these results, we
calculate the dispersion relations for ferromagnetic and antiferromagnetic spin waves. The
relations between the intermediate statistics that magnons obey and the other
two important kinds of intermediate statistics, Haldane–Wu statistics and the
fractional statistics of anyons, are discussed. We also compare the spectrum of the
intermediate-statistics spin wave with the exact solution of the one-dimensional
s = 1/2
Heisenberg model, which is obtained by the Bethe ansatz method. For ferromagnets, we
take the contributions from the interaction between magnons (the quartic contribution),
the next-to-nearest-neighbor interaction, and the dipolar interaction into account for
comparison with the experiment.