We show that the holographic complexity = volume proposal satisfies a very general notion of momentum/complexity correspondence (PC), based on the momentum constraint of general relativity. It ...relates the rate of complexity variation with an appropriate matter momentum flux through spacelike extremal surfaces. This formalizes the intuitive idea that "gravitational clumping" of matter increases complexity, and the required notion of "infall momentum" is shown to have a Newtonian avatar which expresses this idea. The proposed form of the PC correspondence is found to be exact for any solution of Einstein's equations in 2 + 1 dimensions, and any spherically symmetric solution in arbitrary dimensions, generalizing all previous calculations using spherical thin shells. Gravitational radiation enters through a correction which does not have a straightforward interpretation as a PC correspondence. Other obstructions to an exact PC duality have a topological origin and arise in the presence of wormholes.
A
bstract
Holographic complexity, in the guise of the Complexity = Volume prescription, comes equipped with a natural correspondence between its rate of growth and the average infall momentum of ...matter in the bulk. This Momentum/Complexity correspondence can be related to an integrated version of the momentum constraint of general relativity. In this paper we propose a generalization, using the full Codazzi equations as a starting point, which successfully accounts for purely gravitational contributions to infall momentum. The proposed formula is explicitly checked in an exact pp-wave solution of the vacuum Einstein equations.
Terminal holographic complexity Barbón, J. L. F.; Martín-García, J.
The journal of high energy physics,
06/2018, Letnik:
2018, Številka:
6
Journal Article
Recenzirano
Odprti dostop
A
bstract
We introduce a quasilocal version of holographic complexity adapted to ‘terminal states’ such as spacelike singularities. We use a modification of the action-complexity ansatz, restricted ...to the past domain of dependence of the terminal set, and study a number of examples whose symmetry permits explicit evaluation, to conclude that this quantity enjoys monotonicity properties after the addition of appropriate counterterms. A notion of ‘complexity density’ can be defined for singularities by a coarse-graining procedure. This definition assigns finite complexity density to black hole singularities but vanishing complexity density to either generic FRW singularities or chaotic BKL singularities. We comment on the similarities and differences with Penrose’s Weyl curvature criterion.
The class Myxomycetes consists of free-living protists characterised by their complex life cycle, which includes both microscopic (amoebae, flagellates and cists) and macroscopic stages ...(spore-bearing fruiting bodies, sclerotia, andplasmodia). Withinit, theorder Physarales,
with more than 450 recognised species, constitutes the largest group. Although previous studies have shown the polyphyly of some of the traditionally accepted genera, its internal phylogenetic relationships have remained uncertain so far, and together with the lack of data for some keyspecies,
itprevented any taxonomic and nomenclatural revisions. We have compiled a substantially expanded data setinterms of both taxon sampling and molecular data, including most of the genera described to date and four unlinked DNA regions, for which we provide partial sequences: nSSU, EF-1α
, α-Tub, and mtSSU, analysed through maximum likelihood and Bayesian methods. Our results confirm that the family Didymiaceae is paraphyletic to the rest of Physarales. Within Didymiaceae s. lat., the recent reinstatement of the genus Polyschismium
for most species traditionally ascribed to Lepidoderma, except for the type (Ronikieretal.2022), is further supported here, as well as the definite inclusion of the genus Mucilago in Didymium and Lepidoderma s. str.(L. tigrinum) in Diderma
(Prikhodkoetal.2023). Additionally, thegenus Diachea is redefined to include some species previously treated in Physaraceae (Craterium spp. with true columella). Within the monophyletic family Physaraceae, most genera are recovered as polyphyletic, suggesting that
they should be no longer accepted as currently defined. However, the lack of resolution of some relationships within Physaraceae prevents us from resuscitating or creating several new genera to mitigate polyphyly. Among the well-defined groups with clear molecular signatures, we propose
two taxonomic and nomenclatural changes at generic level:1) a new genus, Nannengaella, is proposed for a major clade containing Physarum globuliferum and other species with heavily calcified sporophores and, often, a true calcareous columella;2) Lignydium is resurrected
for the clade containing Fuligo muscorum. Additionally, Trichamphora is suggested as the correct name for the clade containing Physarum pezizoideum. The taxonomy and nomenclature of some provisional genera, currently synonymous with Fuligo and Physarum, are
disentangled, and we provide a comprehensive and updated nomenclatural conspectus that can be used when better resolved phylogenies are obtained. In total, 22 new combinations are proposed in different genera. Aprovisional key to the genera of the order is also provided.
A
bstract
We study the relation between entropy and Action Complexity (AC) for various examples of cosmological singularities in General Relativity. The complexity is defined with respect to the ...causal domain of dependence of the singular set, and the entropy is evaluated on the boundary of the same causal domain. We find that, contrary to the situation for black hole singularities, the complexity growth near the singularity is controlled by the dynamics of the entropy
S
, with a characteristic linear relation. This formula is found to apply to singularities with vanishing entropy as well as those with diverging entropy. In obtaining these results it is crucial to take into account the AC expansion counterterm, whose associated length scale must be chosen sufficiently large in order to ensure the expected monotonicity properties of the complexity.
In this work, the applicability of direct analysis in real time coupled to accurate mass spectrometry (DART-MS) to the quantitative determination of triclosan (TCS) in samples with increasing ...complexity, from personal care products to extracts from sewage, is investigated. In the first term, DART-MS spectra of TCS as free phenol and as derivatized species are characterized; thereafter, the effects of several instrumental variables in the detectability of TCS (i.e., temperature, solvent, and compound holder) are discussed. Under final selected conditions, TCS was determined from its M-H
−
ions, without need of derivatization, attaining an instrumental limit of quantification of 5 ng mL
−1
, with a linear response range up to 1000 ng mL
−1
. Complex matrices, such as solid-phase extracts obtained from environmental water samples, moderately inhibited the ionization efficiency of TCS, with signal attenuation percentages in the range of 6 to 57%, depending on the sample type and on the concentration factor provided by the SPE procedure. The accuracy of results obtained by DART-MS was evaluated using liquid chromatography (LC) with MS detection; in both cases, a time-of-flight (TOF) MS instrument was employed for the selective determination of the M−H
−
ions of TCS (
m
/
z
values 286.9439 and 288.9410) using a mass window of 20 ppm. DART-MS did not only provide enough sensitivity to detect the presence of TCS in environmental samples (raw and treated wastewater as well as freeze-dried sludge), but also measured concentrations matched those determined by LC-ESI-TOF-MS, with only slightly higher standard deviations. During analysis of personal care products, containing much higher concentrations of TCS in a less complex matrix, both techniques were equivalent in terms of accuracy and precision.
Graphical abstract
Poor adhesion is a recurrent problem for the wider use of diamond-like carbon (DLC) coatings in industrial applications. In this work, we investigate the effectiveness of high-power impulse magnetron ...sputtering (HiPIMS) metal ion etching to improve the adhesion of DLC coatings on high speed steel substrates. The influence of HiPIMS pretreatment parameters, the metal ion selection for the process and the addition of bonding layers on the adhesion properties were studied. Daimler-Benz and nanoscratch test methods were used to evaluate the adhesion. The elemental composition, morphology and microstructure of the samples were evaluated by EELS, SEM, AFM and HRTEM. In general, samples pretreated with HiPIMS metal ion etching withstand larger critical loads than those pretreated by conventional Ar+ glow discharge and bonding layers. The pretreatment is proven to be very effective at removing surface contaminants and providing a gradual interface. The selection of Cr over Ti contributes to a significant improvement on the adhesion due to the reduction of the oxygen level at the interface thus ensuring an optimal coating-substrate contact and a more compliant structure, which prevents the delamination failure.
•HiPIMS pretreatment method for enhanced DLC adhesion on steel substrates is proposed.•HiPIMS metal ion etching process parameters are optimized for Cr and Ti.•Improved adhesion relates to substrate oxides removal and a gradual interface.•Superior DLC adhesion with Cr due to lower O2 gettering and more compliant interface
Machineries of Persuasion Garcia, Oscar J. Martin; Magnusdottir, Rosa
2019, 2019-04-01, Letnik:
3
eBook
Over the last two decades, public diplomacy has become a central area of research within Cold War studies. Yet, this field has been dominated by studies of the United States' soft power practices. ...However, the so-called 'cultural dimension' of the Cold war was a much more multifaceted phenomenon. Little attention has been paid to European actors' efforts to safeguard a wide range of strategic and political interests by seducing foreign publics. This book includes a series of works which examine the soft power techniques used by various European players to create a climate of public opinion overseas which favored their interests in the Cold war context. This is a relevant book for three reasons. First, it contains a wide variety of case studies, including Western and Eastern, democratic and authoritarian, and core and peripheral European countries. Second, it pays attention to little studied instruments of public diplomacy such as song contests, sport events, tourism and international solidarity campaigns. Third, it not only concentrates on public diplomacy programs deployed by governments, but also on the role played by some non-official actors in the cultural Cold War in Europe
Gas-phase synthesis of nanoparticles with different structural and chemical distribution is reported using a circular magnetron sputtering in an ion cluster source by applying high-power impulses. ...The influence of the pulse characteristics on the final deposit was evaluated on Au nanoparticles. The results have been compared with the more common direct current approach. In addition, it is shown for the first time that high-power impulses in magnetron based gas aggregation sources allows the growth of binary nanoparticles, CoAu in this case, with a variety of crystalline and chemical arrangements which are analyzed at the atomic level.
•Split-CoFeB layers show higher tendency to promote PMA compared to non-split ones.•Saturation magnetization is higher at split-CoFeB layers compared to non-split ones.•Gilbert damping is moderately ...higher in split-CoFeB layers compared to non-split ones.•Split-CoFeB layers combine high magnetic anisotropy and moderate Gilbert damping.
We report on the static and dynamic magnetic properties of W/CoFeB/Ta/CoFeB/MgO stacks, where the CoFeB layer is split in two by a 0.3 nm-thick Ta “dusting” layer. A total CoFeB thickness between 1.2 and 2.4 nm is studied. Perpendicular magnetic anisotropy is obtained for thickness below 1.8 nm even at the as-deposited stacks, and it is enhanced after annealing. Saturation magnetization is 1520 (1440) kA/m before (after) annealing, increased compared to non-split CoFeB layers. Ferromagnetic resonance measurements show that high magnetic anisotropy energy may be achieved (effective anisotropy field 0.571 ± 0.003 T), combined to a moderate Gilbert damping (0.030 ± 0.001). We argue that the above characteristics make the split-CoFeB system advantageous for spintronics applications.
PDF
