First, they are quantized—meaning, they are made of highly unified, spatially extended bundles of field energy called quanta. Each quantum is itself simply a disturbance in a universal field, analogous to a ripple that disturbs the smooth surface of a pond. This field-bundling feature obviously lends a particlelike aspect to quantum fields, because the bundles are somewhat like particles. Bundles can, for example, be counted, whereas the points filling a spatial volume cannot be counted. This countable, digital aspect of quantum fields is not found in classical fields.
