685 research outputs found
The LIOn's share: How the Liberal International Order Contributes to its Own Legitimacy Crisis. Harvard CES Open Forum Series2019-2020
The liberal international order (LIO) is experiencing a legitimacy crisis in its Western heartland. What causes this crisis? Existing approaches focus on the LIO’s unequal allocation of wealth and values that produces losers and thus breeds dissatisfaction. Yet, why this dissatisfaction translates into a delegitimation of the order rather than a contestation over policies remains unaccounted for. Complementing the cultural and economic backlash hypotheses, this paper advances an institutionalist explanationfor the current crisis of the LIO, which accounts for the growing resistance to the LIO with a political backlash hypothesis. Our argument is that the institutional characteristics of the LIO’s political order trigger self-undermining processes by inciting opposition that cannot be politically accommodated and is thus bound to turn into polity contestation. In particular, we hold that IOs’ predominantly technocratic legitimation rationale on the one hand, and their increasing political authority with distributional effects on the other, create a democracy gap. It implies that avenues to absorb opposition through input channels are largely missing and thus incite the erosion of the LIO’s general acceptance. We illustrate the plausibility of this argument with evidence from the European Union (EU) as well as the international regimes on trade and human rights
Secure communication with single-photon two-qubit states
We propose a cryptographic scheme that is deterministic: Alice sends single
photons to Bob, and each and every photon detected supplies one key bit -- no
photon is wasted. This is in marked contrast to other schemes in which a random
process decides whether the next photon sent will contribute to the key or not.
The determinism is achieved by preparing the photons in two-qubit states,
rather than the one-qubit states used in conventional schemes. In particular,
we consider the realistic situation in which one qubit is the photon
polarization, the other a spatial alternative. Further, we show how one can
exploit the deterministic nature for direct secure communication, that is:
without the need for establishing a shared key first.Comment: 9 pages, 1 figure, 3 tables; final versio
Quantum Brownian motion at strong dissipation probed by superconducting tunnel junctions
We have studied the temporal evolution of a quantum system subjected to
strong dissipation at ultra-low temperatures where the system-bath interaction
represents the leading energy scale. In this regime, theory predicts the time
evolution of the system to follow a generalization of the classical
Smoluchowski description, the quantum Smoluchowski equation, thus, exhibiting
quantum Brownian motion characteristics. For this purpose, we have investigated
the phase dynamics of a superconducting tunnel junction in the presence of high
damping. We performed current-biased measurements on the small-capacitance
Josephson junction of a scanning tunneling microscope placed in a low impedance
environment at milli-Kelvin temperatures. We can describe our experimental
findings by a quantum diffusion model with high accuracy in agreement with
theoretical predications based on the quantum Smoluchowski equation. In this
way we experimentally demonstrate that quantum systems subjected to strong
dissipation follow quasi-classical dynamics with significant quantum effects as
the leading corrections.Comment: 5 pages, 4 figure
Fully Coupled Forced Response Analysis of Nonlinear Turbine Blade Vibrations in the Frequency Domain
For the first time, a fully-coupled Harmonic Balance method is developed for
the forced response of turbomachinery blades. The method is applied to a
state-of-the-art model of a turbine bladed disk with interlocked shrouds
subjected to wake-induced loading. The recurrent opening and closing of the
pre-loaded shroud contact causes a softening effect, leading to turning points
in the amplitude-frequency curve near resonance. Therefore, the coupled solver
is embedded into a numerical path continuation framework. Two variants are
developed: the coupled continuation of the solution path, and the coupled
re-iteration of selected solution points. While the re-iteration variant is
slightly more costly per solution point, it has the important advantage that it
can be run completely in parallel, which substantially reduces the wall clock
time. It is shown that wake- and vibration-induced flow fields do not linearly
superimpose, leading to a severe underestimation of the resonant vibration
level by the influence-coefficient-based state-of-the-art methods (which rely
on this linearity assumption).Comment: 24 pages, 14 figures, preprint submitted to Journal of Computers and
Structure
Ascertaining the Values of , , and of a Polarization Qubit
In the 1987 spin retrodiction puzzle of Vaidman, Aharonov, and Albert one is
challenged to ascertain the values of , , and of
a spin-1/2 particle by utilizing entanglement. We report the experimental
realization of a quantum-optical version in which the outcome of an
intermediate polarization projection is inferred by exploiting single-photon
two-qubit quantum gates. The experimental success probability is consistently
above the 90.2% threshold of the optimal one-qubit strategy, with an average
success probability of 95.6%.Comment: 4 pages, 2 figures; final version with new title and new abstract; to
appear in Physical Review Letter
Average transmission probability of a random stack
The transmission through a stack of identical slabs that are separated by
gaps with random widths is usually treated by calculating the average of the
logarithm of the transmission probability. We show how to calculate the average
of the transmission probability itself with the aid of a recurrence relation
and derive analytical upper and lower bounds. The upper bound, when used as an
approximation for the transmission probability, is unreasonably good and we
conjecture that it is asymptotically exact.Comment: 10 pages, 6 figure
Improved arteriogenesis with simultaneous skeletal muscle repair in ischemic tissue by SCL plus multipotent adult progenitor cell clones from peripheral blood
Background: The CD34- murine stem cell line RM26 cloned from peripheral blood mononuclear cells has been shown to generate hematopoietic progeny in lethally irradiated animals. The peripheral blood-derived cell clones expresses a variety of mesodermal and erythroid/myeloid transcription factors suggesting a multipotent differentiation potential like the bone marrow-derived `multipotent adult progenitor cells' (MAP-C). Methods: SCL+ CD34- RM26 cells were transfused intravenously into mice suffering from chronic hind-limb ischemia, evaluating the effect of stem cells on collateral artery growth and simultaneous skeletal muscle repair. Results: RM26 cells are capable of differentiating in vitro into endothelial cells when cultured on the appropriate collagen matrix. Activation of the SCL stem cell enhancer (SCL+) is mediated through the binding to two Ets and one GATA site and cells start to express milieu- and growth condition-dependent levels of the endothelial markers CD31 (PECAM) and Flt-1 (VEGF-R1). Intravenously infused RM26 cells significantly improved the collateral blood flow (arteriogenesis) and neo-angiogenesis formation in a murine hind-limb ischemia transplant model. Although transplanted RM26 cells did not integrate into the growing collateral arteries, cells were found adjacent to local arteriogenesis, but instead integrated into the ischemic skeletal muscle exclusively in the affected limb for simultaneous tissue repair. Conclusion: These data suggest that molecularly primed hem-/mesangioblast-type adult progenitor cells can circulate in the peripheral blood improving perfusion of tissues with chronic ischemia and extending beyond the vascular compartment. Copyright (C) 2004 S. Karger AG, Basel
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