The phrase "a physical difference in" is correct and usable in written English.
It can be used when discussing variations or distinctions in physical characteristics among individuals, objects, or groups.
Example: "There is a physical difference in the size and shape of the leaves between the two plant species."
Alternatives: "a tangible distinction in" or "a measurable variation in".
What are we to make of these differences between the two fields U and U′? Do they betoken any physical difference in gravitational realities?
The requirement here is that the difference between a predicate's being true of a given object and its being false of it should, in all cases, be a physical difference: "nothing happens in the world, not the flutter of an eyelid, not the flicker of a thought, without some redistribution of microphysical states….
The show's creators, Denise Cramsey (a producer of "Extreme Makeover: Home Edition") and Cheryl Hines (a star of "Curb Your Enthusiasm"), have clearly made a huge physical difference in the schools they've chosen to feature, beginning on Friday with the Enterprise Middle School in Compton, Calif.
Many classification schemes have been proposed, but these are often based solely on differences in the appearance of light curves and may not always reflect a true physical difference in the progenitors of the explosions.
We observed a striking physical difference in immune response between larvae ingesting SBW25 compared to Pf-5.
There is an actual, physical, difference in their brains; you can't become a serial killer by reading about one, any more than you can get magical powers from reading "Harry Potter".
This may be a result of either a chemical or physical difference in the body surface (i.e. chitin) that is associated with a recent molt.
For the physical difference parameter, we observed a trend for an increased magnitude of the BOLD signal as a function of physical difference in the ROIs defined from the TVA localizer and the precuneus and a decreased magnitude of BOLD signal in the right IFGs/insulae (Fig. 3 physical difference panels).
My head took about a month to clear, but when it did I felt a huge, absolutely physical difference in my mental capacity, moods and mental state.
However, it is not know whether the metrics of face space follow the linear distance metrics used to make physically equivalent stimuli in this experiment, and the authors acknowledged that controlling for physical difference in a two-dimensional image does not guarantee equivalent perceptual differences between faces.
