Parathyroid pathology: Its relation to choice of operation for hyperparathyroidism

Variation principle for the time depende

Variation principle for the time dependence of density operators and its relation to linear decoupling procedures for propagators

✍ Esper Dalgaard 📂 Article 📅 1980 🏛 John Wiley and Sons 🌐 English ⚖ 500 KB

## Abstract A modified form of Frenkel's time‐dependent variation principle, suggested by McLachlan for state vectors, is employed to discuss the optimal time evolution of a density operator ρ(__t__). An __ansatz__ is made for this operator such that __i__(__d__ρ/__dt__) = [__S__, ρ], where __S__(_