In pages 41-42 of these notes: http://www.damtp.cam.ac.uk/user/tong/qft/two.pdf , it is said that [itex]|\vec{p}|\ll m[/itex] implies [itex]|\ddot{\tilde{\phi}}|\ll m|\dot{\tilde{\phi}}|[/itex]

Why is this so?

Why is this so?

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