Multistability of a Josephson parametric amplifier coupled to a mechanical resonator

We study the dynamics of Josephson Parametric Amplifier (JPA) coupled to a mechanical oscillator, as realised with a dc Superconducting Quantum Interference Device (SQUID) with an embedded movable arm. We analyse this system in the regime when the frequency of the mechanical oscillator is comparable in magnitude with the plasma oscillation of the SQUID. When the nano-mechanical resonator is driven, it strongly affects the dynamics of the JPA. We show that this coupling can considerably modify the dynamics of JPA and induce its multistability rather than common bistability. This analysis is relevant if one considers a JPA for detection of mechanical motion.Comment: 8 pages, 5 figures, accepted for publication in Phys. Rev.

ACP-EU joint parliamentary assembly at crossroads

Similar to other European institutions where no legally binding decisions are taken, media hardly pay attention to the ACP-EU Joint Parliamentary Assembly (JPA). At best it is prey to criticism about costly political tourism. However, while some serious challenges exist, the JPA constitutes a relevant actor in the EU’s network of inter-parliamentary diplomacy. Looking beyond the formal aspects helps revealing its added value

A Grothendieck-Lefschetz theorem for equivariant Picard groups

We prove a Grothendieck-Lefschetz theorem for equivariant Picard groups of non-singular varieties with finite group actions.Comment: 7 pages; to appear in JPA

Emergence of Benzimidazole- and Strobilurin-Quinone Outside Inhibitor-Resistant Strains of <em>Colletotrichum gloeosporioides</em> sensu lato, the Causal Fungus of Japanese Pear Anthracnose, and Alternative Fungicides to Resistant Strains

Japanese pear anthracnose (JPA) can cause severe tree defoliation during the growing season. Infected trees become weak and produce fewer flower buds the following spring. This economically serious fungal plant disease has affected cultivated pears in Japan since 1910. Initially, JPA was controlled by benzimidazole fungicides. However, benzimidazole-resistant pathogen strains emerged in the late 1990s, and the range of JPA has expanded in Japan. Since then strobilurin-quinone outside inhibitors (ST-QoIs) such as azoxystrobin and kresoxim-methyl became popular, but ST-QoI-resistant pathogen strains appeared. By 2005, JPA control became difficult once again. In this chapter, we outline the history of JPA fungicide resistance problems, assess advantages and disadvantages of available fungicide options, and develop JPA management strategies based on evidences we obtained from a series of field and lab studies

Wild hypersurfaces

Complete hypersurfaces of dimension at least 2 and multiplicity at least 4 have wild Cohen-Macaulay type.Comment: 16 pages. v2 incorporates referee's suggested revisions; to appear in JPA

Understanding the saturation power of Josephson Parametric Amplifiers made from SQUIDs arrays

We report on the implementation and detailed modelling of a Josephson Parametric Amplifier (JPA) made from an array of eighty Superconducting QUantum Interference Devices (SQUIDs), forming a non-linear quarter-wave resonator. This device was fabricated using a very simple single step fabrication process. It shows a large bandwidth (45 MHz), an operating frequency tunable between 5.9 GHz and 6.8 GHz and a large input saturation power (-117 dBm) when biased to obtain 20 dB of gain. Despite the length of the SQUID array being comparable to the wavelength, we present a model based on an effective non-linear LC series resonator that quantitatively describes these figures of merit without fitting parameters. Our work illustrates the advantage of using array-based JPA since a single-SQUID device showing the same bandwidth and resonant frequency would display a saturation power 15 dB lower.Comment: 12 pages, 9 figures, Appendices include