Erratum: Optimizing for an arbitrary perfect entangler. II. Application [Phys. Rev. A 91 , 062307 (2015)]
Equations (26) and (27) of our article contain a typographical error and should read...
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Engineering topics
Calarco, Tommaso
Publications and source records attributed to Calarco, Tommaso.
Optimizing for an arbitrary perfect entangler. II. Application
The difficulty of an optimization task in quantum information science depends on the proper mathematical expression of the physical target. In this paper we demonstrate the power of optimization functionals targeting an arbitrary perfect two-qubit entangler, which allow generation of a maximally entangled state from some initial product state. We show for two quantum information platforms of current interest, i.e., nitrogen vacancy centers in diamond and superconducting Josephson junctions, that an arbitrary perfect entangler can be reached faster and with higher fidelity than both specific two-qubit gates and local equivalence classes of two-qubit gates. Our results are obtained using two independent optimization approaches, underscoring the critical role of the optimization target.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Quantum superpositions of crystalline structures
A procedure is discussed for creating coherent superpositions of motional states of ion strings. The motional states are across the structural transition linear-zigzag, and their coherent superposition is achieved by means of spin-dependent forces, such that a coherent superposition of the electronic states of one ion evolves into an entangled state between the chain's internal and external degrees of freedom. It is shown that the creation of such an entangled state can be revealed by performing Ramsey interferometry with one ion of the chain.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Chopped random-basis quantum optimization
In this work, we describe in detail the chopped random basis (CRAB) optimal control technique recently introduced to optimize time-dependent density matrix renormalization group simulations [P. Doria, T. Calarco, and S. Montangero, Phys. Rev. Lett. 106, 190501 (2011)]. Here, we study the efficiency of this control technique in optimizing different quantum processes and we show that in the considered cases we obtain results equivalent to those obtained via different optimal control methods while using less resources. We propose the CRAB optimization as a general and versatile optimal control technique.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗