Final answer:
The given information does not pertain to an arithmetic sequence, hence it is not possible to determine the common difference as the term a^3 = 0 suggests that 'a' is zero.
Step-by-step explanation:
The question contains a typo and does not reflect an arithmetic sequence. Instead, it appears to present an equation in the form of a^7 - 2a^4 = 1, where also a^3 = 0. To find the common difference of an arithmetic sequence, one would need two or more consecutive terms of the sequence or a formulaic representation of the sequence that includes the common difference (usually denoted by 'd').
Since the provided information does not match the criteria for an arithmetic sequence, and considering a^3 = 0 likely indicates that 'a' is zero (rendering the arithmetic sequence a constant), it is not possible to determine the common difference from the given information.