Understanding Planck Length and Time in Relation to Spacetime and Acceleration

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Planck length and Planck time are considered constants, but they are approximate scales rather than exact values. As an observer accelerates to subluminal velocities, the perception of spacetime can change, affecting measurements of length and time. While these units themselves cannot be "stretched" or "squashed," the numerical representation of an object's length or time span in Planck units may vary for different observers. This indicates that the measurement of physical quantities in Planck units lacks a universal physical meaning across different frames of reference. Ultimately, the discussion highlights the complexity of measuring spacetime in relation to acceleration.
DevonG
Planck length and Planck time are constants, correct?

If spacetime changes for an observer who accelerates to subluminal velocities, what happens to these units? If they're constant I'm guessing they can't be "stretched" or "squashed". So do they change in number for a given measurement (say, the length of a pencil at rest) as you accelerate?
 
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The length of an object, given in Planck units, can be different for different observers. Similar with a time span.
There is nothing wrong with that. It just means that "the length of X in Planck units in some arbitrary specific frame" has no special physical meaning.
 
Planck length and Planck time are constants, correct?
Planck length and time are approximate scales, not exact values.
 

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In an inertial frame of reference (IFR), there are two fixed points, A and B, which share an entangled state $$ \frac{1}{\sqrt{2}}(|0>_A|1>_B+|1>_A|0>_B) $$ At point A, a measurement is made. The state then collapses to $$ |a>_A|b>_B, \{a,b\}=\{0,1\} $$ We assume that A has the state ##|a>_A## and B has ##|b>_B## simultaneously, i.e., when their synchronized clocks both read time T However, in other inertial frames, due to the relativity of simultaneity, the moment when B has ##|b>_B##...
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