10^{10}Li spectrum from 11^{11}Li fragmentation

A recently developed time dependent model for the excitation of a nucleon from a bound state to a continuum resonant state in the system n+core is applied to the study of the population of the low energy continuum of the unbound $^{10}$Li system obtained from $^{11}$Li fragmentation. Comparison of the model results to new data from the GSI laboratory suggests that the reaction mechanism is dominated by final state effects rather than by the sudden process, but for the population of the l=0 virtual state, in which case the two mechanisms give almost identical results. There is also, for the first time, a clear evidence for the population of a d$_{5/2}$ resonance in $^{10}$Li.Comment: 15 pages, 4 figures, 3 tables. Accepted for publication in Nucl.Phys.

Hamiltonian for coupled flux qubits

An effective Hamiltonian is derived for two coupled three-Josephson-junction (3JJ) qubits. This is not quite trivial, for the customary "free" 3JJ Hamiltonian is written in the limit of zero inductance L. Neglecting the self-flux is already dubious for one qubit when it comes to readout, and becomes untenable when discussing inductive coupling. First, inductance effects are analyzed for a single qubit. For small L, the self-flux is a "fast variable" which can be eliminated adiabatically. However, the commonly used junction phases are_not_ appropriate "slow variables", and instead one introduces degrees of freedom which are decoupled from the loop current to leading order. In the quantum case, the zero-point fluctuations (LC oscillations) in the loop current diverge as L->0. Fortunately, they merely renormalize the Josephson couplings of the effective (two-phase) theory. In the coupled case, the strong zero-point fluctuations render the full (six-phase) wave function significantly entangled in leading order. However, in going to the four-phase theory, this uncontrollable entanglement is integrated out completely, leaving a computationally usable mutual-inductance term of the expected form as the effective interaction.Comment: REVTeX4, 16pp., one figure. N.B.: "Alec" is my first, and "Maassen van den Brink" my family name. Informal note. v2: completely rewritten; correction of final result and major expansion. v3: added numerical verification plus a discussion of Ref. [2

Determining the Electron-Phonon Coupling Strength in Correlated Electron Systems from Resonant Inelastic X-ray Scattering

We show that high resolution Resonant Inelastic X-ray Scattering (RIXS) provides direct, element-specific and momentum-resolved information on the electron-phonon (e-p) coupling strength. Our theoretical analysis demonstrates that the e-p coupling can be extracted from RIXS spectra by determining the differential phonon scattering cross section. An alternative, very direct manner to extract the coupling is to use the one and two-phonon loss ratio, which is governed by the e-p coupling strength and the core-hole life-time. This allows measurement of the e-p coupling on an absolute energy scale.Comment: 4 pages, 3 figure

Maximally Supersymmetric Yang-Mills in five dimensions in light-cone superspace

We formulate maximally supersymmetric Yang-Mills theory in five dimensions in light-cone superspace. The light-cone Hamiltonian is of the quadratic form and the theory can be understood as an oxidation of the N=4 Super Yang-Mills Theory in four dimensions. We specifically study three-point counterterms and show how these counterterms vanish on-shell. This study is a preliminary to set up the technique in order to study possible four-point counterterms.Comment: 25 pages, typos corrected, references adde

Theoretical prediction of multiferroicity in double perovskite Y2_2NiMnO6_6

We put forward double perovskites of the R$_2$NiMnO$_6$ family (with $R$ a rare-earth atom) as a new class of multiferroics on the basis of {\it ab initio} density functional calculations. We show that changing $R$ from La to Y drives the ground-state from ferromagnetic to antiferromagnetic with $\uparrow\uparrow\downarrow\downarrow$ spin patterns. This E$^*$-type ordering breaks inversion symmetry and generates a ferroelectric polarization of few $\mu C/cm^2$. By analyzing a model Hamiltonian we understand the microscopic origin of this transition and show that an external electric field can be used to tune the transition, thus allowing electrical control of the magnetization.Comment: 4 pages, 3 figure

Diamond electro-optomechanical resonators integrated in nanophotonic circuits

Diamond integrated photonic devices are promising candidates for emerging applications in nanophotonics and quantum optics. Here we demonstrate active modulation of diamond nanophotonic circuits by exploiting mechanical degrees of freedom in free-standing diamond electro-optomechanical resonators. We obtain high quality factors up to 9600, allowing us to read out the driven nanomechanical response with integrated optical interferometers with high sensitivity. We are able to excite higher order mechanical modes up to 115 MHz and observe the nanomechanical response also under ambient conditions.Comment: 15 pages, 4 figure

A Strategic Implementation of the Average Tree Solution for Cycle-Free Graph Games

In this note we provide a strategic implementation of the Average Tree solution for zero-monotonic cycle-free graph games. That is, we propose a non-cooperative mechanism of which the unique subgame perfect equilibrium payoffs correspond to the average hierarchical outcome of the game. This mechanism takes into account that a player is only able to communicate with other players (i.e., to make proposals about a division of the surplus of cooperation) when they are connected in the graph. © 2013 Elsevier Inc