PHY.3:1 - Problem frame

Use this pattern when you need to determine what a physical process or device could accomplish before choosing its detailed mechanism, or when a familiar physical prohibition appears to rule out a proposed change. A candidate may have an acceptable energy balance yet require an unavailable preparation, consume a resource that was omitted, or perform differently on inputs that one device is supposed to handle.

The first useful result is a necessary condition on the requested performance, a conditional exclusion of a class of proposals, or a changed premise that opens a different construction. You obtain it by describing the complete physical transformation and constructing a comparison that the applicable physical laws constrain. “Permitted” here means allowed under those physical premises.

You need a working description of the requested effect, the resources and surrounding systems it may use, and the physical principles relevant to that effect. A qualitative argument can suffice. A quantitative result also needs the quantities and mathematical operations in its chosen comparison. The two worked cases require different preparation: energy exchanges and elementary ratios in the first, state vectors and inner products in the second. Obtain an unfamiliar physical premise or calculation from a suitable source or collaborator and retain the conditions on which its answer depends.

When an established bound already answers the same question under the same physical conditions, apply it directly. A measurement of a particular device, estimation of an unknown parameter and design of a mechanism have their own methods. Return here when their result changes the allowed transformation or the reach of a physical restriction.