Identification of a Kitaev quantum spin liquid by magnetic field angle dependence

Quantum spin liquids realize massive entanglement and fractional quasiparticles from localized spins, proposed as an avenue for quantum science and technology. In particular, topological quantum computations are suggested in the non-abelian phase of Kitaev quantum spin liquid with Majorana fermions, and detection of Majorana fermions is one of the most outstanding problems in modern condensed matter physics. Here, we propose a concrete way to identify the non-abelian Kitaev quantum spin liquid by magnetic field angle dependence. Topologically protected critical lines exist on a plane of magnetic field angles, and their shapes are determined by microscopic spin interactions. A chirality operator plays a key role in demonstrating microscopic dependences of the critical lines. We also show that the chirality operator can be used to evaluate topological properties of the non-abelian Kitaev quantum spin liquid without relying on Majorana fermion descriptions. Experimental criteria for the non-abelian spin liquid state are provided for future experiments.

Динамическая восприимчивость нанокомпозита пористое стекло/Ga-In-Sn в области сверхпроводимости

Interest to studies of gallium alloys increased recently in relation to their prospective applications for self-healing superconducting connections and wires. Special attention is focused on superconductive properties of nanostructured alloys. In the present work we studied the ac susceptibility of a porous glass/Ga-In-Sn nanocomposite within the temperature range from 1.9 to 8 K at bias fields up to 5 T. Two superconducting phase transitions were revealed with temperatures of 5.6 and 3.1 K. Phase diagrams were created. Positive curvature of the parts of critical lines was demonstrated and treated within the framework of a proximity effect model. Vortex activation barriers were found from shifts of the maxima of the imaginary parts of susceptibility with changing the ac frequency. A bend was shown on the field dependence of the activation barriers.

The Post-Screen through Virtual Reality, Holograms and Light Projections

Screens are ubiquitous today. They display information; present image worlds; are portable; connect to mobile networks; mesmerize. However, contemporary screen media also seek to eliminate the presence of the screen and the visibilities of its boundaries. As what is image becomes increasingly indistinguishable against the viewer's actual surroundings, this unsettling prompts re-examination about not only what is the screen, but also how the screen demarcates and what it stands for in relation to our understanding of our realities in, outside and against images. Through case studies drawn from three media technologies - Virtual Reality; holograms; and light projections - this book develops new theories of the surfaces on and spaces in which images are displayed today, interrogating critical lines between art and life; virtuality and actuality; truth and lies. What we have today is not just the contestation of the real against illusion or the unreal, but the disappearance itself of difference and a gluttony of the unreal which both connect up to current politics of distorted truth values and corrupted terms of information. <i>The Post-Screen through Virtual Reality, Holograms and Light Projections: Where Screen Boundaries Lie</i> is thus about not only where the image's borders and demarcations are established, but also the screen boundary as the instrumentation of today's intense virtualizations that do not tell the truth. In all this, a new imagination for images emerges, with a new space for cultures of presence and absence, definitions of object and representation, and understandings of dis- and re-placement - the post-screen.

The Post-Screen Through Virtual Reality, Holograms and Light Projections

Screens are ubiquitous today. They display information; present image worlds; are portable; connect to mobile networks; mesmerize. However, contemporary screen media also seek to eliminate the presence of the screen and the visibilities of its boundaries. As what is image becomes increasingly indistinguishable against the viewer’s actual surroundings, this unsettling prompts re-examination about not only what is the screen, but also how the screen demarcates and what it stands for in relation to our understanding of our realities in, outside and against images. Through case studies drawn from three media technologies – Virtual Reality; holograms; and light projections – this book develops new theories of the surfaces on and spaces in which images are displayed today, interrogating critical lines between art and life; virtuality and actuality; truth and lies. What we have today is not just the contestation of the real against illusion or the unreal, but the disappearance itself of difference and a gluttony of the unreal which both connect up to current politics of distorted truth values and corrupted terms of information. The Post-Screen Through Virtual Reality, Holograms and Light Projections: Where Screen Boundaries Lie is thus about not only where the image’s borders and demarcations are established, but also the screen boundary as the instrumentation of today’s intense virtualizations that do not tell the truth. In all this, a new imagination for images emerges, with a new space for cultures of presence and absence, definitions of object and representation, and understandings of dis- and re-placement – the post-screen.

Skin-Friction-Based Identification of the Critical Lines in a Transonic, High Reynolds Number Flow via Temperature-Sensitive Paint

In this contribution, three methodologies based on temperature-sensitive paint (TSP) data were further developed and applied for the optical determination of the critical locations of flow separation and reattachment in compressible, high Reynolds number flows. The methodologies rely on skin-friction extraction approaches developed for low-speed flows, which were adapted in this work to study flow separation and reattachment in the presence of shockwave/boundary-layer interaction. In a first approach, skin-friction topological maps were obtained from time-averaged surface temperature distributions, thus enabling the identification of the critical lines as converging and diverging skin-friction lines. In the other two approaches, the critical lines were identified from the maps of the propagation celerity of temperature perturbations, which were determined from time-resolved TSP data. The experiments were conducted at a freestream Mach number of 0.72 and a chord Reynolds number of 9.7 million in the Transonic Wind Tunnel Göttingen on a VA-2 supercritical airfoil model, which was equipped with two exchangeable TSP modules specifically designed for transonic, high Reynolds number tests. The separation and reattachment lines identified via the three different TSP-based approaches were shown to be in mutual agreement, and were also found to be in agreement with reference experimental and numerical data.

“He dwells alone:” The Image of Completeness in the Self in Cowper’s “The Snail”

Following the critical lines of Psychoanalysis and Existentialism, the present study aims at conveying how William Cowper, the much acclaimed English poet of the 18th century, presents in his 1799 poem “The Snail” the image of an individual possessing completeness in the self. Not only is Cowper’s snail content with life in seclusion, but also abhors the intrusion of an outsider in its private domain. The article aims at investigating how the snail’s world of completeness bears both the somatic and the psychic dimensions and also how the creature exists in that world narcissistically. Concomitantly, the article would probe into the association between the world of the snail and the poet’s longing to attain sufficiency in the self at a time he is left alone. It would be conveyed how the snail of the poem embodies the poet’s projected self in its idealised form, something which following the French psychoanalyst, Jacques Lacan can be called the poet’s “ideal ego,” than an insignificant creature engrossed merely in nourishment on vegetation. Keywords: Cowper, completeness, private world, self, The Snail.

Systematic search for lensed X-ray sources in the CLASH fields

Aims. We exploit the high angular resolution of Chandra to search for unresolved X-ray emission from lensed sources in the field of view of 11 CLASH clusters, whose critical lines and amplification maps were previously obtained with accurate strong-lensing models. We consider a solid angle in the lens plane corresponding to a magnification μ > 1.5, which amounts to a total of ∼100 arcmin2, of which only 10% corresponds to μ > 10. Our main goal is to assess the efficiency of massive clusters as cosmic telescopes to explore the faint end of the X-ray extragalactic source population. Methods. The main obstacle to this study is the overwhelming diffuse X-ray emission from the intracluster medium that encompasses the region with the strongest magnification power. To overcome this aspect, we first searched for X-ray emission from strongly lensed sources that were previously identified in the optical and then performed an untargeted detection of lensed X-ray sources. Results. We detect X-ray emission in either in the soft (0.5−2 keV) or hard (2−7 keV) band in only 9 out of 849 lensed or background optical sources. The stacked emission of the sources without detection does not reveal any signal in any band. Based on the untargeted detection in the soft, hard, and total band images, we find 66 additional X-ray sources without spectroscopic confirmation that are consistent with being lensed (background) sources. Assuming an average redshift distribution consistent with the Chandra Deep Field South survey (CDFS), we estimate their magnification, and after accounting for completeness and sky coverage, measure the soft- and hard-band number counts of lensed X-ray sources for the first time. The results are consistent with current modeling of the population distribution of active galactic nuclei (AGN). The distribution of delensed fluxes of the sources identified in moderately deep CLASH fields reaches a flux limit of ∼10−16 and ∼10−15 erg s−1 cm−2 in the soft and hard bands, respectively, therefore approximately 1.5 orders of magnitude above the flux limit of the CDFS. Conclusions. We conclude that in order to match the depth of the CDFS in exploiting massive clusters as cosmic telescopes, the required number of cluster fields is about two orders of magnitude larger than is offered by the 20 year Chandra archive. At the same time, the discovery of strongly lensed sources close to the critical lines remains an attractive if rare occurrence because the source density in the X-ray sky is low. A significant step forward in this field will be made when future X-ray facilities an angular resolution of ∼1 arcsec and a large effective area will allow the serendipitous discovery of rare, strongly lensed high-z X-ray sources. This will enable studying faint AGN activity in the early Universe and measuring gravitational time delays in the X-ray variability of multiply imaged AGN.

Bounded Religious Automation at Work: Communicating Human Authority in Artificial Intelligence Networks

Existential threats to human work and leadership have been expressed over intensifying human-machine communication, and the development of robots and artificial intelligence (AI). Yet popular texts and techno-centric approaches to AI assume a flat ontology in human-machine communication which obscures power relations governing new technologies, necessitating a bounded automation approach integrating socio-economic influences that shape AI diffusion in distinctive occupational settings. This article advances three critical lines of enquiry to interrogate abstract labor displacement propositions by contextualizing human authority and communication in spiritual work. By explicating the dynamic and relational ways in which clerics strategically manage emerging social robotics, discussion of the case of ‘the world’s first robot monk’ illustrates how organizational leaders can influence AI agents to (re)produce values and cultural realities. In the process, priests strengthen normative regulation of power by aligning epistemic knowledge shared about AI and during human-machine communication to extant understandings of collective ideals.