Optimal control of a collection of parametric oscillators
K. H. Hoffmann, B. Andresen, and P. Salamon
Accepted
The problem of effectively-adiabatic control of a collection of classical harmonic oscillators sharing the same time-dependent frequency is analyzed. The phase differences between the oscillators remain fixed during the process. This fact that leads us to adopting the coordinates: energy, Lagrangian, correlation, which have proved useful in a quantum description and which have the advantage of treating both the classical and quantum problem in one unified framework. A representation theorem showing that two classical oscillators can represent an arbitrary collection of classical or quantum oscillators is proved. A new invariant, the Casimir companion, consisting of a combination of our coordinates is the key to determining the minimum reachable energy. We present a condition for two states to be connectable using 1-jump controls and enumerate all possible switchings for 1-jump effectively-adiabatic controls connecting any initial to any reachable final state. Examples are discussed. One important consequence is that an initially microcanonical ensemble of oscillators will be transformed into another microcanonical ensemble by effectively-adiabatic control. Likewise, a canonical ensemble becomes another canonical ensemble.