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O: Fachverband Oberflächenphysik

O 13: Focus Session: New Trends in Molecular Magnetism (MA jointly with O, TT)

O 13.1: Topical Talk

Montag, 31. März 2014, 15:00–15:30, HSZ 04

Spin dynamics in Molecular Nanomagnets — •Stefano Carretta — Dipartimento di Fisica e Scienze della Terra, Universita' di Parma, I-43124 Parma, Italy

Molecular nanomagnets (MNMs) have been test beds for addressing several quantum phenomena. In particular, one of the major current objectives is to exploit their coherent spin dynamics for quantum information processing (QIP). We show that recently developed instrumentation yields the four-dimensional inelastic-neutron scattering function and enables the direct determination of the spin dynamics [1]. We use the Cr8 antiferromagnetic ring as a benchmark to demonstrate the potential of this approach, which allows us, for instance, to examine how quantum fluctuations propagate along the ring. We show that parameters of the spin Hamiltonian can be reliably calculated ab-initio. In particular, we present a flexible and effective ab-initio scheme to build many-body models for MNMs, and to calculate magnetic exchange couplings and zero-field splittings [2]. We have applied this scheme to three paradigmatic systems, the antiferromagnetic rings Cr8 and Cr7Ni and the single molecule magnet Fe4 and have found excellent agreement with experimental results. At last, we discuss the dynamics of ensembles of spin systems coherently coupled to microwave photons in coplanar waveguide resonators. We introduce a scheme to perform QIP that is based on a hybrid spin-photon qubit encoding [3].

[1] M. Baker et al, Nature Physics 8, 906 (2012); [2] A. Chiesa et al, Phys. Rev. Lett. 110, 157204 (2013); [3] S. Carretta, et al, Phys. Rev. Lett. 111, 110501 (2013).