Applied Casimir Effect technology doesn't unlock wormholes, Autonomous Materials does instead. In ES1 the tech named exactly like the former (link) unlocked wormholes, and in ES2 as well the Trading Companies tab in economy screen has a tip suggesting you to research Applied Casimir Effect tech if you have built HQs, but haven't yet connected any of them to subsidiaries, in order to unlock wormhole travel.

As you can see the tech description does seem to allude to wormholes, but the actual unlocks are seemingly unrelated Population slot and Food bonus improvements instead of making wormholes visible on galaxy map.

Also another minor nitpick: typing "wormhole" into tech tree search bar doesn't show you anything either, likely confusing new players even more.