Dynamics and Noise in dc-SQUID Magnetometer Arrays

The natural behavior of most processes is that whenever they are effected by an external phenomenon the outcome of the system is changed. Hence the output of a process can be changed by the input of the system. Many of these processes have the capability of either being in a steady state while at others times they may be induced into a periodic or oscillating state. This type of behavior is common in a system of equations which is used to detect and measure an external phenomena which will change the state of the system. These systems are generally referred to as sensors. Quite often a sensor's effectiveness is increased once it is in a region where it is oscillating. This, however, is not the only way to enhance effectiveness. If one is to connect the sensors in one of many different ways, generally referred to as a coupling, the sensitivity may be increased. In this work we will demonstrate the behavior of a particular type of sensor, known as dc-SQUID (Superconducting Quantum Interference Device) coupled in a nearest-neighboring scheme. We show that the response of the coupled system to an external magnetic field is greatly increased compared to that of a single SQUID element. Applications of this work include: geological equipment, biomedical equipment such as MRI machines, and applications to homeland defense such as mine detection.