Although this means two such rest periods in any 24-hour period, only one of the rest periods bears any resemblance to what we would call sleep. Mandible and antennae activity is at a much lower level (usually up to 65 per cent lower) than during the other rest period in one 24-hour period, indicating a much deeper "resting" phase.
Basing and McCluskey in 1986 used brain activity recorders on black, red, and soldier ants to determine whether the deeper resting period constituted actual "sleep". A steep decline in brain wave fluctuations supported the "sleep" hypothesis in black and red ants, but surprisingly showed a higher level of brain activity in soldier ants in a deep resting phase.
However there was a proverb saying that learn hardworking from ants that might be came from this phenomena itself they sleep less work more (Most active insects ).
Morover there are many specis of ants so if u want to consider in detail read Myrmecology & Insects Behaviour books.
please see the below video How ants are sleeping