What condition applies to T1 and T2 in thermal relaxation models?

Question: In common thermal relaxation noise modeling, which relation must usually hold for valid T1 and T2 parameters? A) T2 must always be exactly equal to T1 B) T1 must be zero C) T2 must be greater than every gate time by definition D) T2 ≤ 2T1 Correct: D Explanation: Thermal relaxation noise models use T1 and T2 time constants to represent energy relaxation and dephasing behavior. A common validity condition is T2 ≤ 2T1. Topic: quantum computing / noise models / thermal relaxation