1,828 research outputs found
Estimating entanglement of unknown states
The experimental determination of entanglement is a major goal in the quantum
information field. In general the knowledge of the state is required in order
to quantify its entanglement. Here we express a lower bound to the robustness
of entanglement of a state based only on the measurement of the energy
observable and on the calculation of a separability energy. This allows the
estimation of entanglement dismissing the knowledge of the state in question.Comment: 3 pages, 1 figure. Comments welcome. V2: references updated. Accepted
version by Applied Physics Letter
The Geometry of Entanglement Sudden Death
In open quantum systems, entanglement can vanish faster than coherence. This
phenomenon is usually called sudden death of entanglement. In this paper sudden
death of entanglement is discussed from a geometrical point of view, in the
context of two qubits. A classification of possible scenarios is presented,
with important known examples classified. Theoretical and experimental
construction of other examples is suggested as well as large dimensional and
multipartite versions of the effect.Comment: 6 pages, 2 figures, references added, initial paragraph corrected,
sectioning adopted, some parts rewritten; accepted by New J. Phy
Cloning, purification and comparative characterization of two digestive lysozymes from Musca domestica larvae
cDNA coding for two digestive lysozymes (MdL1 and MdL2) of the Musca domestica housefly was cloned and sequenced. MdL2 is a novel minor lysozyme, whereas MdL1 is the major lysozyme thus far purified from M. domestica midgut. MdL1 and MdL2 were expressed as recombinant proteins in Pichia pastoris, purified and characterized. The lytic activities of MdL1 and MdL2 upon Micrococcus lysodeikticus have an acidic pH optimum (4.8) at low ionic strength (μ = 0.02), which shifts towards an even more acidic value, pH 3.8, at a high ionic strength (μ = 0.2). However, the pH optimum of their activities upon 4-methylumbelliferyl N-acetylchitotrioside (4.9) is not affected by ionic strength. These results suggest that the acidic pH optimum is an intrinsic property of MdL1 and MdL2, whereas pH optimum shifts are an effect of the ionic strength on the negatively charged bacterial wall. MdL2 affinity for bacterial cell wall is lower than that of MdL1. Differences in isoelectric point (pI) indicate that MdL2 (pI = 6.7) is less positively charged than MdL1 (pI = 7.7) at their pH optima, which suggests that electrostatic interactions might be involved in substrate binding. In agreement with that finding, MdL1 and MdL2 affinities for bacterial cell wall decrease as ionic strength increases.FAPESPCNP
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The Brazilian monetary and fiscal policies from 2011 to 2017: conventions and crisis
Post Keynesians define conventions as creeds shared by individuals who use them to ground their expectations. Economic policymaking plays a major role in the development of conventions. Thus, this article analyses Brazil’s fiscal and monetary policies over 2011-2017. First, it shows how the monetary policy over 2011-2014 wasted the opportunity to establish a lower base rate in Brazil, what we call ‘the mistakes of the past’. Second, it argues that the austerity policy implemented after 2015 formed the convention that public investments are not needed to boost private investments; this is what we call ‘the loss of future opportunities’
Endogenous systems leadership for education in crises: A framework for inclusive and equitable quality education in low- and middle-income countries
The working paper develops a framework for ‘endogenous systems leadership’ as a means of supporting the distribution of leadership across the local, middle and central tiers of complex education systems in low- and middle-income countries affected by crisis; in ways that respect the values, knowledge, practices and agency of actors in these contexts, which are characterised by the involvement of multiple international partners with a remit to support, and an obligation to respect and not override, local authority and decision-making. The framework identifies entry points for strengthening endogenous systems leadership of inclusive and equitable quality education for all
Correlation between Skp2 expression and nodal metastasis in stage I and II oral squamous cell carcinomas
Geometrically induced singular behavior of entanglement
We show that the geometry of the set of quantum states plays a crucial role
in the behavior of entanglement in different physical systems. More
specifically it is shown that singular points at the border of the set of
unentangled states appear as singularities in the dynamics of entanglement of
smoothly varying quantum states. We illustrate this result by implementing a
photonic parametric down conversion experiment. Moreover, this effect is
connected to recently discovered singularities in condensed matter models.Comment: v2: 4 pags, 4 figs. A discussion before the proof of Proposition 1
and tomographic results were included, Propostion 2 was removed and the
references were fixe
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