When a down and out loser discovers a time portal where he communicates with his arrogant younger self, they attempt to create a lucrative future together, but become mortal enemies and a battle for control in this alternate reality drives him to the brink of psychosis. Refraction is a 98 page feature, psychological thriller in the vein of The Butterfly Effect or Twilight Zone.

Defiantly remove the note at the end these types of comments are best reserved for a pitch not a logline.

The remaining logline describes a situation and a vague plot. What is the main character trying to achieve? Better yet what is he fighting for? Control in an alternate reality is not a clear enough goal for the MC to pursue.

The inciting incident described is the discovery of the portal, following this as the starting point for the story, I find it hard to imagine what the end of the story is. Battling for control in an alternate reality is too vague an action for a logline.
How does he battle? This will constitute most of your act 2 and therefore most of the film you really need to be clear on what this action will be.

It is also difficult to identify the genre it sounds like a comedy from the first half of the logline but then with the introduction of the psychosis it tends dramatic in feel. If this is a comedy better to drop the psychosis but if a drama then best to establish it earlier on as an obstacle perhaps as part of the MC description.

Hope this helps.