Parting layers, ash trays and Ramesside glassmaking: an experimental study

A series of glassmaking and glass colouring replication experiments was undertaken in order to test some of the current hypotheses concerning Late Bronze Age glass production at Qantir-Piramesses. These were based on the model of glassmaking developed in this volume, and aimed in particular to test the behaviour of the parting layer and the local ceramic under the proposed chemical and thermal conditions. Modern ash trays made out of Egyptian Nile silt clay were used as proxies for LBA reaction vessels and crucibles, and both raw glass and coloured glass ingots were produced in them. This experimental study, based on detailed observation and technical studies of archaeological samples from Qantir-Piramesses, not only provides material readily comparable to the archaeological finds, but brings to the forefront practical issues concerning the nature of the parting layer, its application, the melting procedures, the re-use of crucibles, and indirect evidence of primary production, such as the impact of sodium chloride, a major component of plant ashes, on the ceramic. Although this string of experiments does not fully replicate LBA glassmaking technology, much information was obtained and further areas of ambiguity identified

Analytic control methods for high fidelity unitary operations in a weakly nonlinear oscillator

In qubits made from a weakly anharmonic oscillator the leading source of error at short gate times is leakage of population out of the two dimensional Hilbert space that forms the qubit. In this paper we develop a general scheme based on an adiabatic expansion to find pulse shapes that correct this type of error. We find a family of solutions that allows tailoring to what is practical to implement for a specific application. Our result contains and improves the previously developed DRAG technique [F. Motzoi, et. al., Phys. Rev. Lett. 103, 110501 (2009)] and allows a generalization to other non-linear oscillators with more than one leakage transition.Comment: 15 pages, 9 figures, small change

Coupling JOREK and STARWALL for Non-linear Resistive-wall Simulations

The implementation of a resistive-wall extension to the non-linear MHD-code JOREK via a coupling to the vacuum-field code STARWALL is presented along with first applications and benchmark results. Also, non-linear saturation in the presence of a resistive wall is demonstrated. After completion of the ongoing verification process, this code extension will allow to perform non-linear simulations of MHD instabilities in the presence of three-dimensional resistive walls with holes for limited and X-point plasmas.Comment: Contribution for "Theory Of Fusion Plasmas, Joint Varenna - Lausanne International Workshop, Villa Monastero, Varenna, Italy (27.-31.8.2012)", accepted for publication in Journal of Physics Conference Serie

Entanglement of two superconducting qubits in a waveguide cavity via monochromatic two-photon excitation

We report a system where fixed interactions between non-computational levels make bright the otherwise forbidden two-photon 00 --> 11 transition. The system is formed by hand selection and assembly of two discrete component transmon-style superconducting qubits inside a rectangular microwave cavity. The application of a monochromatic drive tuned to this transition induces two-photon Rabi-like oscillations between the ground and doubly-excited states via the Bell basis. The system therefore allows all-microwave two-qubit universal control with the same techniques and hardware required for single qubit control. We report Ramsey-like and spin echo sequences with the generated Bell states, and measure a two-qubit gate fidelity of 90% (unconstrained) and 86% (maximum likelihood estimator).Comment: 5 pages, 4 figures. V2: add supplemental material about the Schrieffer-Wolff transformatio

Gauss sum factorization with cold atoms

We report the first implementation of a Gauss sum factorization algorithm by an internal state Ramsey interferometer using cold atoms. A sequence of appropriately designed light pulses interacts with an ensemble of cold rubidium atoms. The final population in the involved atomic levels determines a Gauss sum. With this technique we factor the number N=263193.Comment: 4 pages, 5 figure

Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence

We measured the ratio $P_{x}/P_{z}$ of the transverse to longitudinal components of polarization transferred from electrons to bound protons in $^{12}\mathrm{C}$ by the $^{12}\mathrm{C}(\vec{e},e'\vec{p})$ process at the Mainz Microtron (MAMI). We observed consistent deviations from unity of this ratio normalized to the free-proton ratio, $(P_{x}/P_{z})_{^{12}\mathrm{C}}/(P_{x}/P_{z})_{^{1}\mathrm{H}}$, for both $s$- and $p$-shell knocked out protons, even though they are embedded in averaged local densities that differ by about a factor of two. The dependence of the double ratio on proton virtuality is similar to the one for knocked out protons from $^{2}\mathrm{H}$ and $^{4}\mathrm{He}$, suggesting a universal behavior. It further implies no dependence on average local nuclear density

Raman spectrum and lattice parameters of MgB2 as a function of pressure

We report Raman spectra and synchrotron x-ray diffraction measurements of lattice parameters of polycrystalline MgB2 under hydrostatic pressure conditions up to 15 GPa. An anomalously broadened Raman band at 620 cm-1 is observed that exhibits a large linear pressure shift of its frequency. The large mode damping and Gruneisen parameter indicate a highly anharmonic nature of the mode, broadly consistent with theoretical predictions for the E2g in-plane boron stretching mode. The results obtained may provide additional constraints on the electron-phonon coupling in the system.Comment: 3 pages, 3 figure

Stability of HEB receivers at THz frequencies

Stability of a hot-electron bolometer (HEB) heterodyne receiver was investigated at frequencies from 0.6THz to 1.9THz. The Allan variance was measured as a function of the integration time and the Allan time was obtained for HEB mixers of different size, as well as with different types of the local oscillator: FIR laser, multiplier chain, and BWO. We have found that due to stronger dependence of the mixer gain and noise vs mixer bias voltage and current the Allan time is shorter for smaller mixers. At 1.6THz the Allan time is 3 sec for 4x0.4μm^2 bolometer, and 0.15-0.2 sec for 1x0.15μm^2 bolometer. Obtained stability apears to be the same for the FIR laser and the mulitplier chain. The Allan time for smaller bolometers increases to 0.4-0.5sec at 0.6-0.7THz LO frequencies. The influence of the IF chain on the obtained results is also analyzed