Quantum dynamics and measurement of single quantum objects.
We consider the dynamics of Superconducting QUantum Interference Device (SQUID)
rings in the presence of time dependent magnetic fields, solving the time dependent
Schrodinger equation computationally. We compare the quantum mechanical behaviour
of the SQUID ring with that of a simple two state system (the ammonia maser), finding
close parallels between these two systems.
We then consider the idea of measurement of macroscopic quantum objects by
modelling the SQUID ring inductively coupled to a classical measurement device (a LC
oscillator circuit). We solve the equations of motion for this coupled system both in the
phenomenological Resistively Shunted Junction plus Capacitance (RSJ+C) model and
within the framework of two models using a purely quantum mechanical SQUID ring.