Quantum behaviour appears to be lost in macroscopic objects. They do not, for example, form superpositions. In this paper I present two schemes that produce multiparticle superpositions of superfluid flow. By studying the effect of external parameters on the superposition, I have found three conditions that must be satisfied for a superposition to form. The energy of the superposition states must be close, there must be a coupling path between the states and other states must not couple strongly. By optimising these conditions, it may be possible to make Schrödinger cat states, useful for metrology and stable qubits.
© 2007 Optical Society of AmericaPDF Article