Cavity QED with separate photon storage and qubit readout modes

We present the realization of a cavity quantum electrodynamics setup in which photons of strongly different lifetimes are engineered in different harmonic modes of the same cavity. We achieve this in a superconducting transmission line resonator with superconducting qubits coupled to the different modes. One cavity mode is strongly coupled to a detection line for qubit state readout, while a second long lifetime mode is used for photon storage and coherent quantum operations. We demonstrate sideband based measurement of photon coherence, generation of n photon Fock states and the scaling of the sideband Rabi frequency with the square root of n using a scheme that may be extended to realize sideband based two-qubit logic gates.Comment: 4 pages, 5 figures, version with high resolution figures available at http://qudev.ethz.ch/content/science/PubsPapers.htm

Mechanisms underlying cell death in ischemia-like damage to the rat spinal cord in vitro

New spinal cord injury (SCI) cases are frequently due to non-traumatic causes, including vascular disorders. To develop mechanism-based neuroprotective strategies for acute SCI requires full understanding of the early pathophysiological changes to prevent disability and paralysis. The aim of our study was to identify the molecular and cellular mechanisms of cell death triggered by a pathological medium (PM) mimicking ischemia in the rat spinal cord in vitro. We previously showed that extracellular Mg2+ (1 mM) worsened PM-induced damage and inhibited locomotor function. The present study indicated that 1 h of PM+Mg2+ application induced delayed pyknosis chiefly in the spinal white matter via overactivation of poly (ADP-ribose) polymerase 1 (PARP1), suggesting cell death mediated by the process of parthanatos that was largely suppressed by pharmacological block of PARP-1. Gray matter damage was less intense and concentrated in dorsal horn neurons and motoneurons that became immunoreactive for the mitochondrial apoptosis-inducing factor (the intracellular effector of parthanatos) translocated into the nucleus to induce chromatin condensation and DNA fragmentation. Immunoreactivity to TRPM ion channels believed to be involved in ischemic brain damage was also investigated. TRPM2 channel expression was enhanced 24 h later in dorsal horn and motoneurons, whereas TRPM7 channel expression concomitantly decreased. Conversely, TRPM7 expression was found earlier (3 h) in white matter cells, whereas TRPM2 remained undetectable. Simulating acute ischemic-like damage in vitro in the presence of Mg2+ showed how, during the first 24 h, this divalent cation unveiled differential vulnerability of white matter cells and motoneurons, with distinct changes in their TRPM expression. \ua9 2013 Macmillan Publishers Limited All rights reserved

Polymeric Ablation Induced by Free Burning Arcs in Air

We investigate the influence of switching arcs on different polymers and their interaction. We describe a set of experiments on a simplified model geometry typical for low voltage switchgear. In a broad range of experimental conditions and parameters such as arc current, polymeric material or contact material, the voltage, the mass loss and the corresponding pressure build-up are examined. From this raw data, we deduce the arc influence on the ablation process as well as the feedback on some arc plasma properties

Using Sideband Transitions for Two-Qubit Operations in Superconducting Circuits

We demonstrate time resolved driving of two-photon blue sideband transitions between superconducting qubits and a transmission line resonator. Using the sidebands, we implement a pulse sequence that first entangles one qubit with the resonator, and subsequently distributes the entanglement between two qubits. We show generation of 75% fidelity Bell states by this method. The full density matrix of the two qubit system is extracted using joint measurement and quantum state tomography, and shows close agreement with numerical simulation. The scheme is potentially extendable to a scalable universal gate for quantum computation.Comment: 4 pages, 5 figures, version with high resolution figures available at http://qudev.ethz.ch/content/science/PubsPapers.htm

LE MOLTE VERSIONI DELLA CONSEGUENZA LOGICA

This thesis is on the concept of logical consequence (LC) and it is divided into two parts. In the first one, I show that LC: (1) was not important in eminent logicians (like Aristotle) (2) has been described in several different ways (preservation of truth from premises to conclusion, formality, necessity of thought, following a rule, to transform what is a ground for the premises into a ground for the conclusion, \u2026) and by different methods (predication, natural language, formal language, per se entities, Theory of Types, Set-theory, derivation in a formal calculus, variation of the non-logical parts of the sentences, \u2026). I explain how LC became one of the central notions of contemporary logic, why it was not important in many authors (in certain cases, until very recent years), which forms had the logics in which LC was not important, the many and important relations among LC and extra-logical (metaphysical, epistemological, pragmatic, \u2026) notions. It shows that we cannot simply take for granted that there is an intuitive concept of LC or even a natural concept of LC, since it has always been formulated and become understandable and important only in connection with non-logical notions and different scientific aims. The authors or the schools studied in this first section are: Aristotle, Descartes, Kant, Bolzano, Frege, the algebra of logic, the axiomatic study of mathematical theories, Brouwer, Gentzen, Tarski, Etchemendy and Prawitz. In the second part of my thesis, I explore the seminal Tarski\u2019s idea to consider LC as a closure operator and further developed by \u141os, Suszko, W\uf3jcicki, Czelakowski and the Barcelona Group. I define LC as a structural closure relation on the algebra of formulas, without taking into account its syntactical or semantic definition. I examine the philosophical ideas lying behind this conception and I explore different definitions (e.g., non-monotone consequence). Then I explore how we can define LC by a calculus (Hilbert-calculus and Natural Deduction Calculus) or by a semantic system (I consider predicative language too) and I explain the philosophical implications of these different points of view. In the last chapter I explore how we can define LC by matrices and the philosophical implication of this method. I study Lindenbaum matrices, Lindenbaum bundles, Lindenbaum-Tarski algebras and I investigate the relation among some properties of logical systems and Lindenbaum matrices

An alternative search for the electron capture of Te-123

A search for the electron capture of Te-123 has been performed using CdZnTe detectors. After a measuring time of 195 h no signal could be found resulting in a lower half-life limt of $T_{1/2} > 3.2 \cdot 10^{16}$ yrs (95 % CL) for this process. This clearly discriminates between existing experimental results which differ by six orders of magnitude and our data are in strong favour of the result with longer half-lifes.Comment: 2 pages, 2 eps-figures, reanalysis of data set