High-gain weakly nonlinear flux-modulated Josephson parametric amplifier using a SQUID-array

We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of 8 superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude-gain x bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the non-degenerate mode of operation. Phase sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.Comment: 7 pages, 4 figures, 23 reference

Multiplexed Readout of Transmon Qubits with Josephson Bifurcation Amplifiers

Achieving individual qubit readout is a major challenge in the development of scalable superconducting quantum processors. We have implemented the multiplexed readout of a four transmon qubit circuit using non-linear resonators operated as Josephson bifurcation amplifiers. We demonstrate the simultaneous measurement of Rabi oscillations of the four transmons. We find that multiplexed Josephson bifurcation is a high-fidelity readout method, the scalability of which is not limited by the need of a large bandwidth nearly quantum-limited amplifier as is the case with linear readout resonators.Comment: 7 pages, 6 figures, and 31 reference

Revisión sistemática del trilobite oryctocefálido Protoryctocephalus arcticus Geyer & Peel, 2011 del Cámbrico inferior (Piso 4) de Balang, China meridional

The oryctocephalid trilobites from the traditional ‘lower-middle Cambrian’ represent key tools for international correlation. The trilobite zones in South China around the Cambrian Series 2-Miaolingian are made using oryctocephalids. One of the trilobite zones suggested is based on Protoryctocephalus arcticus. Protoryctocephalus from the Balang area in South China was described as Protoryctocephalus wuxunensis, also from the Cambrian Series 2 of South China. However, Protoryctocephalus from Balang shows different morphological features such as different glabellar shape, presence of a transglabellar S1 and more segments in the trunk. These features match with Protoryctocephalus arcticus from the Cambrian Series 2 of Greenland.Los trilobites oryctocefálidos del tránsito ‘Cámbrico inferior-medio’ representan herramientas clave para la correlación internacional. Las zonas de trilobites en China meridional a través del tránsito Serie cámbrica 2-Miaolingiense se basan en este grupo fósil. La base de una de estas zonas de trilobites se sitúa con la aparición de Protoryctocephalus arcticus. El género Protoryctocephalus, procedente del área de Balang en China meridional, fue descrito originalmente como Protoryctocephalus wuxunensis, también de la serie cámbrica 2 de China meridional. Sin embargo, en Balang Protoryctocephalus muestra diferentes caracteres morfológicos, tales como la forma glabelar, la presencia de un surco transglabelar S1 y más segmentos en el tronco (tórax + pigidio). Estos caracteres cuadran mejor con Protoryctocephalus arcticus de la Serie cámbrica 2 of Groenlandia

Coulomb charging energy for arbitrary tunneling strength

The Coulomb energy of a small metallic island coupled to an electrode by a tunnel junction is investigated. We employ Monte Carlo simulations to determine the effective charging energy for arbitrary tunneling strength. For small tunneling conductance, the data agree with analytical results based on a perturbative treatment of electron tunneling, while for very strong tunneling recent semiclassical results for large conductance are approached. The data allow for an identification of the range of validity of various analytical predictions.Comment: 4 pages REVTeX, incl 3 figures, to appear in Europhys.Let

Bioestratigrafía a partir de trilobites de las Formaciones de Balang y “Tsinghsutung” (Serie Cámbrica 2, Piso 4) en el área de Balang, Jianhe, Guizhou, China meridional

Ongoing work is carrying out in the Balang and “Tsinghsutung” formations to aim a suitable candidate for the base of the Cambrian Series 2, Stage 4. The revision of the trilobite systematics and zonation shed light about the stratigraphic distribution and the geographical distribution of the new trilobite-based zones in the Balang area (South China). Our results suggest that either Oryctocarella duyunensis or Arthricocephalus chauveaui could be good candidates since they also occur in the Eoaagnostus roddyi-Arthricocephalus chauveaui Zone of the Henson Gletscher Formation, North Greenland.Se está trabajando en las formaciones de Balang y “Tsinghsutung” para encontrar un candidato adecuado para la base de la Serie 2 del Cámbrico, Piso 4. La revisión de la sistemática y zonación bioestratigáfica de los trilobites arroja luz sobre las distribuciones estratigráfica y biogeográfica de las nuevas zonas basadas en trilobites en el área de Balang (China meridional). Nuestros resultados sugieren que tanto Oryctocarella duyunensis como Arthricocephalus chauveaui podrían ser buenos candidatos, ya que también se encuentran en la Zona de Eoaagnostus roddyi-Arthricocephalus chauveaui de la Formación de Henson Gletscher, al norte de Groenlandia

Primate modularity and evolution: first anatomical network analysis of primate head and neck musculoskeletal system

Network theory is increasingly being used to study morphological modularity and integration. Anatomical network analysis (AnNA) is a framework for quantitatively characterizing the topological organization of anatomical structures and providing an operational way to compare structural integration and modularity. Here we apply AnNA for the first time to study the macroevolution of the musculoskeletal system of the head and neck in primates and their closest living relatives, paying special attention to the evolution of structures associated with facial and vocal communication. We show that well-defined left and right facial modules are plesiomorphic for primates, while anthropoids consistently have asymmetrical facial modules that include structures of both sides, a change likely related to the ability to display more complex, asymmetrical facial expressions. However, no clear trends in network organization were found regarding the evolution of structures related to speech. Remarkably, the increase in the number of head and neck muscles – and thus of musculoskeletal structures – in human evolution led to a decrease in network density and complexity in humans

Reaching the quantum limit of sensitivity in electron spin resonance

We report pulsed electron-spin resonance (ESR) measurements on an ensemble of Bismuth donors in Silicon cooled at 10mK in a dilution refrigerator. Using a Josephson parametric microwave amplifier combined with high-quality factor superconducting micro-resonators cooled at millikelvin temperatures, we improve the state-of-the-art sensitivity of inductive ESR detection by nearly 4 orders of magnitude. We demonstrate the detection of 1700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise (SNR) ratio, reduced to just 150 spins by averaging a single Carr-Purcell-Meiboom-Gill sequence. This unprecedented sensitivity reaches the limit set by quantum fluctuations of the electromagnetic field instead of thermal or technical noise, which constitutes a novel regime for magnetic resonance.Comment: Main text : 10 pages, 4 figures. Supplementary text : 16 pages, 8 figure

Computed tomography evaluation of gilt growth performance and carcass quality under feeding restrictions and compensatory growth effects on the sensory quality of pork

Restricted feed can affect the body composition of pigs. Body composition can be studied non-destructively in live pigs using computed tomography (CT). The objective was to investigate the effect of different feeding restriction strategies on the productive and carcass quality parameters of gilts during growth via CT images and the effects of such strategies on meat quality, sensory properties and consumer preferences. Moreover, we sought to determine whether CT is a suitable tool for this purpose in this type of study. Thus, 36 Pietrain x (Large White x Landrace) gilts were assigned to the following three feeding strategies: 1) ad libitum feeding (AL) during all fattening periods (AL-AL); 2) AL feeding between 30 and 70 kg target body weight (TBW) followed by restriction (84% of AL) until 120 kg TBW (AL-RV); and 3) restriction feeding (78% of AL) between 30 and 70 kg TBW followed by AL until 120 kg TBW (RV-AL). When the pigs reached 30, 70, 100 and 120 kg, they were CT scanned to obtain the carcass composition parameters. At 120 kg TBW, the pigs were slaughtered, and the carcass and meat quality was determined. The loins were collected for trained panel evaluation and consumer tests. The panellists evaluated the odour, flavour and texture attributes of cooked loins. A total of 120 consumers scored the overall acceptability, tenderness, odour and flavour. The results showed a decrease of 76% and 80% in the average daily gain and average daily feed intake during the restriction period compared with the ad libitum in the growth phase, respectively, and a decrease of 89% and 87% in these parameters during the fattening phase, respectively. A restriction reduces the body fat content during the period of the restriction. Differences in the carcass and cut composition and meat quality were not observed at the end of the experiment among the treatments. Regarding sensory quality, meat from the animals in the AL-AL treatment was tougher than that from animals in the RV-AL and AL-RV treatments. Nevertheless, these differences were not detected by consumers, who did not provide significantly different scores for acceptability. Thus, when preparing feeding strategies, these results should be considered to optimize costs and increase benefits. Furthermore, computed tomography represents a non-destructive technology suitable for determining carcass composition before slaughter.info:eu-repo/semantics/acceptedVersio

Algebraic Quantization, Good Operators and Fractional Quantum Numbers

The problems arising when quantizing systems with periodic boundary conditions are analysed, in an algebraic (group-) quantization scheme, and the ``failure" of the Ehrenfest theorem is clarified in terms of the already defined notion of {\it good} (and {\it bad}) operators. The analysis of ``constrained" Heisenberg-Weyl groups according to this quantization scheme reveals the possibility for new quantum (fractional) numbers extending those allowed for Chern classes in traditional Geometric Quantization. This study is illustrated with the examples of the free particle on the circumference and the charged particle in a homogeneous magnetic field on the torus, both examples featuring ``anomalous" operators, non-equivalent quantization and the latter, fractional quantum numbers. These provide the rationale behind flux quantization in superconducting rings and Fractional Quantum Hall Effect, respectively.Comment: 29 pages, latex, 1 figure included with EPSF. Revised version with minor changes intended to clarify notation. Acepted for publication in Comm. Math. Phy