Reconstructing the quantum state of oscillator networks with a single qubit

We introduce a scheme to reconstruct arbitrary states of networks composed of quantum oscillators-e. g., the motionalstate of trapped ions or the radiation state of coupled cavities. The scheme involves minimal resources and minimal access, in the sense that it (i) requires only the interaction between a one-qubit probe and a single node of the network; (ii) provides the Weyl characteristic function of the network directly from the data, avoiding any tomographic transformation; (iii) involves the tuning of only one coupling parameter. In addition, we show that a number of quantum properties can be extracted without full reconstruction of the state. The scheme can be used for probing quantum simulations of anharmonic many-body systems and quantum computations with continuous variables. Experimental implementation with trapped ions is also discussed and shown to be within reach of current technology.

Quantum state storage and processing for polarization qubits in an inhomogeneously broadened Λ-type three-level medium

We address the propagation of a single photon pulse with two polarization components, i.e., a polarization qubit, in an inhomogeneously broadened "phaseonium" \Lambda-type three-level medium. We combine some of the non-trivial propagation effects characteristic for this kind of coherently prepared systems and the controlled reversible inhomogeneous broadening technique to propose several quantum information processing applications, such as a protocol for polarization qubit filtering and sieving as well as a tunable polarization beam splitter. Moreover, we show that, by imposing a spatial variation of the atomic coherence phase, an effcient quantum memory for the incident polarization qubit can be also implemented in \Lambda-type three-level systems.

Pyroelectric and piezoelectric scanning microscopy applied to reveal the bipolar state of 4-iodo-4 '-nitrobiphenyl (INBP)

Two recent scanning probe techniques were applied to investigate the bipolar twin state of 4-iodo-4'-nitrobiphenyl (INBP) crystals. Solution grown crystals of INBP show typically a morphology which does not express that of a mono-domain polar structure (Fdd2, mm2). From previous X-ray diffraction a twinning volume ratio of similar to 70 : 30 is now explained by two unipolar domains (Flack parameter: 0.075(29)) of opposite orientation of the molecular dipoles, joined by a transition zone showing a width of similar to 140 mm. Scanning pyroelectric microscopy (SPEM) demonstrates a continuous transition of the polarization P from +P into -P across the zone. Application of piezoelectric force microscopy (PFM) confirms unipolar alignment of INBP molecules down to a resolution of similar to 20 nm. A previously proposed real structure for INBP crystals built from lamellae with antiparallel alignment is thus rejected. Anomalous X-ray scattering was used to determine the absolute molecular orientation in the two domains. End faces of the polar axis 2 are thus made up by NO2 groups. Using a previously determined negative pyroelectric coefficient pc leads to a confirmation also by a SPEM analysis. Calculated values for functional group interactions (D...A), (A...A), (D...D) and the stochastic theory of polarity formation allow us to predict that NO2 groups should terminate corresponding faces. Following the present analysis, INBP may represent a first example undergoing dipole reversal upon growth to end up in a bipolar state.

Right-Wing Violence in Germany: Assessing the Objectives, Personalities and Terror Trail of the National Socialist Underground and the State's Response to It

In the last five years the forces of organised right-wing extremism have made electoral advances across many states in contemporary Europe. Germany has not been immune and the extreme right party, the National Democratic Party of Germany won its first seat in the European Parliament since 1989. The recent successes of the extreme right pose issues for European society about tolerance and immigration policy, but this scene has also been associated with an upsurge in racially motivated political violence and acts of right-wing terrorism. Much of this violence is perpetrated by small neo-Nazi styled groups. This paper looks at the most notorious and recent of such groups to emerge in Germany, the National Socialist Underground. The paper explores the origins and personalities behind this terror cell, provides derails of its criminal activities and murder spree, and questions why it took so long for the authorities to identify the NSU.

Evidence for a glassy state in strongly driven carbon

Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

Development of dynamic structural testing to current state-of-the-art hybrid testing

Even though computational power used for structural analysis is ever increasing, there is still a fundamental need for testing in structural engineering, either for validation of complex numerical models or to assess material behaviour. In addition to analysis of structures using scale models, many structural engineers are aware to some extent of cyclic and shake-table test methods, but less so of ‘hybrid testing’. The latter is a combination of physical testing (e.g. hydraulic
actuators) and computational modelling (e.g. finite element modelling). Over the past 40 years, hybrid testing of engineering structures has developed from concept through to maturity to become a reliable and accurate dynamic testing technique. The hybrid test method provides users with some additional benefits that standard dynamic testing methods do not, and the method is more cost-effective in comparison to shake-table testing. This article aims to provide the reader with a basic understanding of the hybrid test method, including its contextual development and potential as a dynamic testing technique.