  We explore the correlations and entanglements of exact-diagonalized
few-electron wave functions in a quantum dot in magnetic fields without the
Zeeman splitting. With the increase of the field, the lowest states with
different spins gradually form a narrow band and the electronic states undergo
a transition from liquids to rotating Wigner molecules which are accompanied by
different characters of charge correlations. For both the liquid and crystal
states, the spin conditional probability densities show magnetic couplings
between the particles which depend on the particle numbers, the total spins and
the angular momenta of the states. The von Neumann entropies show the
spin-dependent entanglements between electrons. The regular magnetic-coupling
oscillations and converging entanglement entropies emerge in the rotating
Wigner molecular states.
