Swampland (physics)

In physics, the term swampland is used in contrast to the term "landscape" to indicate physical theories or aspects of such theories that could be true if gravity were not an issue but are not compatible with string theory. Recent developments in string theory suggest that the string theory landscape of False vacua is vast.

It is natural to ask if the landscape is as vast as allowed by consistent-looking effective field theories. Some authors (like Cumrun Vafa) suggest that is not the case and that the landscape is surrounded by an even larger swampland of consistent-looking semiclassical effective field theories, which are actually inconsistent.

Some proposed swampland criteria are the following:

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