We investigate theoretically the use of time-varying magnetic fields to selectively create and manipulate quasiparticles in magnetically trapped Bose condensates. To maximize the transition matrix element connecting two desired quasiparticle states, the spatial symmetry of the applied magnetic field must be tailored to exploit the different spatial distributions of magnetization in the two quasiparticle states. This ``spatial magnetic resonance'' effect is analogous to the Franck-Condon factor in electric dipole transitions in diatomic molecules. Experimentally, the spatial magnetic resonance technique may allow the creation of coherences between quasiparticle states, the inversion of quasiparticle state populations, the measurement of quasiparticle lifetimes (
T1) and decoherence times (
T2), the creation of quasiparticle echoes, etc., in analogy with conventional spin magnetic resonance.
A study was conducted to demonstrate the manipulation of molecular beams with electric and magnetic fields. Seeded pulsed supersonic expansions were employed to conduct the investigations. The conservative forces exerted further downstream by the electric and magnetic fields enabled the researchers to manipulate and control the shape and the position of the distribution in the six-dimensional phase-space. All of the original experimental geometries were devised to create strong magnetic or electric field gradients to efficiently deflect particles from the beam axis. It was demonstrated that a detailed understanding of the influence of the external field on the energy level structure of the molecules was required for the manipulation of molecules with electric or magnetic fields.