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发帖数: 99 | 1 How many string theories are there?
There are several ways theorists can build string theories. Start
with the elementary ingredient: a wiggling tiny string. Next decide:
should it be an open string or a closed string? Then ask: will I
settle for only bosons ( particles that transmit forces) or will I ask
for fermions, too (particles that make up matter)? (Remember that in
string theory, a particle is like a note played on the string.)
If the answer to the last question is "Bosons only, please!" |
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