The Defiant's focal array is utilized to generate a subspace tensor matrix
A focal array was a component of the navigational deflector of Federation starships, used for the generation and projection of specific types of energy.
In 2372, Doctor Lenara Kahn utilized the USS Defiant's focal array in her attempts to create a stable artificial wormhole. The procedure involved launching a target drone and then using the focal array to generate a subspace tensor matrix. The drone would then send out a magneton pulse to react with the matrix, forming an opening in the spacetime continuum. Doctor Kahn's efforts met with limited success, creating a wormhole, although it was short-lived. (DS9: "Rejoined")