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## Motion planing for an ensemble of Bloch equations towards the south pole with smooth bounded control

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Ulisses Alves Maciel Neto
• Fonction : Auteur
Paulo Sergio Pereira da Silva
• Fonction : Auteur
• PersonId : 866348
Pierre Rouchon

#### Résumé

One considers the control problem of an ensemble of Bloch equations (non-interacting half-spins) in a static magnetic field B0. The state M (t, •) belongs to the Sobolev space H 1 ((ω * , ω *), S 2) where the parameter ω ∈ (ω * , ω *) is the Larmor frequency. Previous works have constructed a Lyapunov based stabilizing feedback in a convenient H 1-norm that assures local L ∞convergence of the initial state M0(ω) to the south pole, solving locally the approximate steering problem from M0 towards the south pole. However, the corresponding control law contains a comb of periodic π-Rabi pulses (Dirac impulses), corresponding to strongly unbounded control. The present work propose smooth uniformly bounded time-varying controls for this local steering problem, where the Rabi pulses are replaced by adiabatic following smooth pulses. Furthermore, simulations show that this new strategy produces faster convergence, even for initial conditions "relatively far" from the south pole.

### Dates et versions

hal-03325203 , version 1 (24-08-2021)

### Identifiants

• HAL Id : hal-03325203 , version 1

### Citer

Ulisses Alves Maciel Neto, Paulo Sergio Pereira da Silva, Pierre Rouchon. Motion planing for an ensemble of Bloch equations towards the south pole with smooth bounded control. 2021. ⟨hal-03325203⟩

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