The subprime mortgage crisis was caused by hedge funds, banks, and insurance companies. The first two created mortgage-backed securities. The insurance companies covered them with credit default swaps. Demand for mortgages led to an asset bubble in housing.
The field of dielectrics is a branch of physics that covers how insulating materials separate different electrical charges in a capacitor. A capacitor is a device with two metal plates of opposite charges, with a dielectric insulating material in between the keeps the charges separate.
Dielectric relaxation is the momentary delay (or lag) in the dielectric constant of a material. This is usually caused by the delay in molecular polarization with respect to a changing electric field in a dielectric medium (e.g., inside capacitors or between two large conducting surfaces).