Quantum Error Correction with magnetic molecules

Quantum algorithms often assume independent spin qubits to produce trivial $|\uparrow\rangle=|0\rangle$, $|\downarrow\rangle=|1\rangle$ mappings. This can be unrealistic in many solid-state implementations with sizeable magnetic interactions. Here we show that the lower part of the spectrum of a molecule containing three exchange-coupled metal ions with $S=1/2$ and $I=1/2$ is equivalent to nine electron-nuclear qubits. We derive the relation between spin states and qubit states in reasonable parameter ranges for the rare earth $^{159}$Tb$^{3+}$ and for the transition metal Cu$^{2+}$, and study the possibility to implement Shor's Quantum Error Correction code on such a molecule. We also discuss recently developed molecular systems that could be adequate from an experimental point of view.Comment: 5 pages, 3 figures, 2 table

Magnetic exchange interaction in a pair of orbitally degenerate ions: Magnetic anisotropy of [Ti2Cl9]−3

The theory of the kinetic exchange in a pair of orbitally degenerate ions developed by the authors [J. Phys. Chem. A 102, 200 (1998)] is applied to the case of face-shared bioctahedral dimer (overall D3h-symmetry). The effective kinetic exchange Hamiltonian is found for a 2T2–2T2 system taking into account all relevant transfer pathways and charge-transfer crystal field states. The influence of different transfer integrals involved in the kinetic exchange on the energy pattern and magnetic properties of the system is examined. The role of other related interactions (trigonal crystal field, spin–orbit coupling) is also discussed in detail. Using the pseudoangular momentum representation and the technique of the irreducible tensor operators of R3-group we give a general outlook on the nontrivial symmetry properties of the effective Hamiltonian for the D3h-pair, and on the magnetic anisotropy arising from the orbital interactions specific for the case of orbital degeneracy. The magnetic properties of the binuclear unit [Ti2Cl9]−3 in Cs3Ti2Cl9 are discussed with a special emphasis on the magnetic anisotropy experimentally observed in this system. The existing exchange models for [Ti2Cl9]−3 and the concept of the effective Hamiltonian are discussed in the context of the present [email protected] ; [email protected] ; [email protected] ; [email protected]

Tunable crossover between one- and three-dimensional magnetic dynamics in C oII single-chain magnets organized by halogen bonding

Low-temperature magnetometry, ac susceptibility, and calorimetry have been employed to study Co-based single-chain magnets (SCMs) organized through halogen bonding. Magnetic hysteresis and maxima in the dc and ac susceptibilities, respectively, confirm the SCM behavior of the system. Several characteristic magnetic relaxation regimes are observed at different temperatures, which can be associated with both intra- and interchain exchange interactions. Remarkably, tweaking the rate at which an external magnetic field is swept along the axis of the chains enables a controlled transition between the one- and three-dimensional dynamics. Experiments on an isostructural Co-based SCM system crystallized with different halogens do not show three-dimensional dynamics, illustrating the importance of halogen bonding on the control of interchain interactions

Tunable crossover between one- and three-dimensional magnetic dynamics in CoII single-chain magnets organized by halogen bonding

Low-temperature magnetometry, ac susceptibility, and calorimetry have been employed to study Co-based single-chain magnets (SCMs) organized through halogen bonding. Magnetic hysteresis and maxima in the dc and ac susceptibilities, respectively, confirm the SCM behavior of the system. Several characteristic magnetic relaxation regimes are observed at different temperatures, which can be associated with both intra- and interchain exchange interactions. Remarkably, tweaking the rate at which an external magnetic field is swept along the axis of the chains enables a controlled transition between the one- and three-dimensional dynamics. Experiments on an isostructural Co-based SCM system crystallized with different halogens do not show three-dimensional dynamics, illustrating the importance of halogen bonding on the control of interchain interactions.A.A. and E.d.B. acknowledge support from the National Science Foundation (DMR No. 1503627). G.M.E., J.M.C.- J., and E.C. acknowledge the Spanish MINECO (Excellence Unit Maria de Maeztu MDM-2015-0538 and Projects No. MAT2014-56143-R, No. CTQ2014-29509-P, and No. CTQ2014-52758-P, and the excellence network NANOMOLNet on molecular nanoscience, Project No. MAT2014-52919-REDC), the EU (COST Action MOLSPIN), and the Generalidad Valenciana (Prometeo Program). F.L. and M.E. acknowledge funding from the MINECO-FEDER through Grant No. MAT2015-68204-R and from Gobierno de Aragon, Grant No. E98-MOLCHIP.Peer Reviewe

Molecular sexing in Kea Nestor notabilis

DNAによる性判別法のミヤマオウムへの利用を目的として､鳥類の性染色体上に存在するCHD(chromo-helicase-DNA binding protein)遺伝子を標的とする2種類のプライマーセットについて検討した。その結果､ミヤマオウムでは､2種類のプライマーセットでDNAの増幅が認められた。しかし､オウム､インコ類においで性判別の報告があるプライマーAの雌雄間で認められる型が異なること から判別ができなかった。一方､ワシ､タカ類のCHD-Wの配列を基に設計されたプライマーBを用いた方法では､ミヤマオウムのW染色体由来の増幅産物のみが検出されることから性判別が可能となった。また､対照として用いたヨウムは､2種類のプライマーセットで性判別が可能であったことから､プライマーBは､他の鳥種でも性判別のできる可能性が示唆された

CoordMaude Simplifying Formal Coordination Specifications of Cooperation Environments

AbstractDeveloping concurrent applications in cooperative environments is an arduous task. This is mainly due to the fact that it is very difficult to specify the synchronized interaction between the entities composing the system. Using coordination models makes this task easier. The latest trends in this area suggest that to manage the successful implementation of complex systems, coordination models must support some key features regarding the coordination constraints: their separated specification, their unanticipated evolution and their dynamic change. However, supporting these features is not only a technical challenge: it must be also guaranteed that the application of a separately specified coordination pattern to a set of encapsulated entities, or the change of the coordination constraints in an already running software system will not produce semantic errors. This is just the problem focused in this paper. In particular, a method for generating formal interpretable specifications reproducing coordinated environments is presented. The method is based on the Coordinated Roles coordination model and makes use of Maude as a formal language. The benefits obtained are: (i) easy specification using the coordination model syntax, (ii) automatic generation of the corresponding formal specification and (iii) simulation of system behaviour

Q-dependence of the inelastic neutron scattering cross section for molecular spin clusters with high molecular symmetry

For powder samples of polynuclear metal complexes the dependence of the inelastic neutron scattering intensity on the momentum transfer Q is known to be described by a combination of so called interference terms. They reflect the interplay between the geometrical structure of the compound and the spatial properties of the wave functions involved in the transition. In this work, it is shown that the Q-dependence is strongly interrelated with the molecular symmetry of molecular nanomagnets, and, if the molecular symmetry is high enough, is actually completely determined by it. A general formalism connecting spatial symmetry and interference terms is developed. The arguments are detailed for cyclic spin clusters, as experimentally realized by e.g. the octanuclear molecular wheel Cr8, and the star like tetranuclear cluster Fe4.Comment: 8 pages, 1 figures, REVTEX