Black Space Research Articles

Conformal Killing horizons

For time dependent black hole space–times the event horizon cannot be described by a Killing horizon. In the case when the space–time admits a timelike conformal Killing field, which becomes null on a boundary called the conformal stationary limit surface, one can locally describe the expanding event horizon by using this boundary, provided that it is a null geodesic hypersurface. In this case the boundary is called a conformal Killing horizon and is shown to be null and geodesic if and only if the twist of the conformal Killing trajectories on the hypersurface vanishes. Moreover if the space–time is conformally related to a stationary asymptotically flat black hole space–time, it is shown that this hypersurface is globally equivalent to the event horizon, provided that the conformal factor goes to a constant at null infinity. When the conformal stationary limit surface does not coincide with the conformal Killing horizon, a generalization of the weak rigidity theorem which establishes the conformal Killing property of the event horizon and the rigidity of its rotation is obtained. A physical definition of surface gravity for conformal Killing horizons is given, which is then used to formulate a generalized zeroth law of black hole physics.

Asymptotic quasinormal frequencies for black holes in nonasymptotically flat space–times

The exact computation of asymptotic quasinormal frequencies is a technical problem which involves the analytic continuation of a Schrödinger-type equation to the complex plane and then performing a method of monodromy matching at several poles in the plane. While this method was successfully used in asymptotically flat space–time, as applied to both the Schwarzschild and Reissner–Nordstro/m solutions, its extension to nonasymptotically flat space–times has not been achieved yet. In this work it is shown how to extend the method to this case, with the explicit analysis of Schwarzschild–de Sitter and large Schwarzschild–anti–de Sitter black holes, both in four dimensions. We obtain, for the first time, analytic expressions for the asymptotic quasinormal frequencies of these black hole space–times, and our results match previous numerical calculations with great accuracy. We also list some results concerning the general classification of asymptotic quasinormal frequencies in d-dimensional space–times.

Asymptotic states in two black hole moduli space

We discuss the quantum states in the moduli space, which constructed with maximally charged dilaton black holes. Considering the quantum mechanics in the moduli space, we obtain the asymptotic states for the near-coincident black holes and the widely separated black holes. We study the scattering process of the dilaton black holes with the asymptotic states. In the scattering process, the quantum effects in the black hole moduli space are investigated.

Space–time slices and surfaces of revolution

Under certain conditions, a (1+1)-dimensional slice ĝ of a spherically symmetric black hole space–time can be equivariantly embedded in (2+1)-dimensional Minkowski space. The embedding depends on a real parameter that corresponds physically to the surface gravity κ of the black hole horizon. Under conditions that turn out to be closely related, a real surface that possesses rotational symmetry can be equivariantly embedded in three-dimensional Euclidean space. The embedding does not obviously depend on a parameter. However, the Gaussian curvature is given by a simple formula: If the metric is written g=φ(r)−1 dr2+φ(r)dθ2, then Kg=−12φ″(r). This note shows that metrics g and ĝ occur in dual pairs, and that the embeddings described above are orthogonal facets of a single phenomenon. In particular, the metrics and their respective embeddings differ by a Wick rotation that preserves the ambient symmetry. Consequently, the embedding of g depends on a real parameter. The ambient space is not smooth, and κ is inversely proportional to the cone angle at the axis of rotation. Further, the Gaussian curvature of ĝ is given by a simple formula that seems not to be widely known.

Islands and autochthons

This article, the first in a two-part series, examines the ramifications of the complex relationships between race and space for definitions of the nation and national identity in Rhodesia and Zimbabwe. Most generally, the workings of race and space helped polarize Rhodesia and Zimbabwe between what was set up as ‘white’ and ‘black’, and limit the struggle for power and claims on belonging to those two poles. Racial identity was inscribed into spatial sensibilities and organization so that white space (the city) functioned as a series of islands and black space (the countryside) activated organic assertions of autochthony. More specifically, race and space informed the creation of an intermediate racial category, ‘Coloured’, with no substantive claim to a ‘real’ or ‘full’ identity and with no authoritative claim to the physical soil of the country.

Afro-Gynocentric Darwinism in the Drama of George Elroy Boyd

Nationalism and fascism begin at home and take their sustenance from the family undergoing a crisis, particularly one of identity. Given the brutal tragedy of the four-century-long African slave trade (with its bloodily efficient exploitation, sexual and economic, plus often liquidation, of its human capital), its diasporic survivors, especially intellectuals and artists, focus necessarily on the situation – read plight – of the Black family. Certes, the nouns family, identity, and crisis are virtual synonyms in the literature of the African Atlantic, a cultural geography that includes Canada (as much as it does the better-known ‘Neo-African’ spaces of the United States, the Caribbean, Latin America and Western Europe). Of course, a signal balm for these familial identity crises involves the efficacy – and risks – of cultural nationalism. Thus, two dramas by African-Nova Scotian – or Africadian—— playwright George Elroy Boyd depict Black familial strife that provokes acts congruent with nationalism – and fascism. Boyd’s teleplay Consecrated Ground (1983, 1996) relates the struggle of a Black woman, Clarice, to bury her dead infant son in Black community space, despite the objections of a white-controlled metropolis. His play, Gideon’s Blues (1996), narrates the events that prod a Black mother to murder her adult son and only child. Boyd examines the African-Canadian family and its race, class and gender issues, to excavate the tensions between an attractively protective cultural nationalism and a sorrowfully deranging, self-destructive fascism.

Bosonic and fermionic entropy of black holes with different temperatures on horizon surface

By using the method of quantum statistics, we derive directly the partition functions of bosonic and fermionic field in the black hole space–time with different temperatures on horizon surface. The statistical entropy of the black hole is obtained by an improved brick-wall method. When we choose a proper parameter in our results, we can obtain that the entropy of the black hole is proportional to the area of horizon. In our result, there do not exist any neglected term or divergent logarithmic term as given in the original brick-wall method. We have avoided the difficulty in solving the wave equation of the scalar and Dirac field. A simple and direct way of studying entropy of the black hole is given.

Evaluation of Moisture Sensitivity of Bituminous Mixtures by a Complex Modulus Approach

Various laboratory tests are used to evaluate the moisture sensitivity of bituminous mixtures. However, most of them are destructive and require a large number of specimens. Consequently, they do not permit continuous monitoring of the deterioration in mechanical performance, much less measurement of the recovery of this performance, as water evaporates during the drying process. Monitoring of the stiffness modulus could provide a clearer picture of the process of deterioration and recovery that occurs during an immersion-drying cycle. However, during the specimen immersion phases, bitumen ages and hardens, and its stiffness modulus increases. Thus, the action of water simultaneously produces deterioration in the bitumen-aggregate bond and hardening of the binder; these two processes lead to opposing responses and prevent making a clear appraisal of the bituminous mixture's ability to withstand the action of water. Evaluating the mechanical characteristics of bituminous mixtures with a Cole—Cole plot or in black space provides new possibilities for isolating the effect of water at the bitumen-aggregate interface from the effect of the binder.

Re-imagining the Shape and Borders of Black Political Space

Re-imagining the Shape and Borders of Black Political Space

Quantum scattering in two black hole moduli space

We discuss the quantum scattering process in the moduli space consisting of two maximally charged dilaton black holes. The black hole moduli space geometry has different structures for arbitrary dimensions and various values of dilaton coupling. We study the quantum effects of the different moduli space geometries with scattering process. Then, it is found that there is a resonance state on certain moduli spaces.

FLUID FLOW AND INERTIAL FORCES IN BLACK HOLE SPACE–TIMES

We discuss the nature of the radial and azimuthal components of centrifugal force associated with fluid flows in the equatorial plane of black hole space–times. The equations of motion are solved for the radial and azimuthal components of the three-velocity Vi which are then used in evaluating the nature of the various components of inertial accelerations. It is shown that the reversal of centrifugal force is governed mainly by the dominance of the azimuthal velocity and the reversal occurs for r, mostly at 2m ≲ r ≲ 3m, depending upon the boundary condition.

The Space Machine: Baraka and Science Fiction

Music is the weapon of the Future. (Fela Kuti) is black. Check out any episode of Star Trek. When Captain Kirk and his faithful crew boldly go where no man has gone before, it's a journey into blackness, punctuated with a few bright and shining stars. Maybe that goes without saying. Since Sputnik popped the top of Earth's prophylactic atmosphere, everybody knows the color of space. There are myriad pictures to prove it. But forget pictures for a minute. Approach the question culturally, and it becomes obvious that space is more than just a transparent black background for the space race and its colonialist Enterprise. When Sun Ra, the great theorist and master mage of astro-black mythology, says, Space is the Place, he means that it's the place of blackness: black space. What, then, is the relationship between space and race? A question for science fiction, that vernacular idiom of cultural imagination and critique. While most science fiction remains at best complacent in examining the role of race in techno-scientific culture and its possible futures (having been produced for an adolescent, white middle-class consumer), an insurgence appears to be occurring in the creation of black science fiction, or what a recently published anthology calls speculative fiction from the African Diaspora. That anthology, Dark Matter, gathers together an impressive array of black writers who are producing a distinguished body of black science fiction. Samuel Delaney is no longer the sole brother writing scifi on an otherwise white planet, nor is Octavia Butler its Hottentot Venus, curious queen in foreign climes. From George S. Schulyer to Nalo Hopkinson, from Charles R. Sanders to Tananarive Due, a renaissance--or, maybe better, a naissance--of black science fiction is under way that augurs unimagined possibilities. Walter Mosley suggests why in to the Future, a brief commentary that appears in Dark Matter: genre speaks most clearly to those who are dissatisfied with the way things are: adolescents, post adolescents, escapists, dreamers, and those who have been made to feel powerless. And this may explain the appeal that science fiction holds for a great many African Americans.... Through science fiction you can have a black president, a black world, or simply a say in the way things are. This power to imagine is the first step in changing the world. (405-06) Black science fiction begins by affirming the blackness of space, the material space of social life rather than the transparent space of imperialist expansion. It's the space of this world, and not of the galaxy, that needs a change. Black science fiction dares to imagine such possibilities. In this regard, Amiri Baraka becomes one of its forerunners, and his inclusion among the writers in Dark Matter proves instructive. While accounting for only a small part of his astonishing body of work, Baraka's science fiction asserts the reality that space is black, or will be. Working in close concert with Sun Ra's astro-black mythologizing, but toward even more physical ends, Baraka imagines a future in which space materializes a previously transparent blackness. And his means for pursuing this future is music. Black music is the doomsday weapon of Baraka's science fiction. Although it would be overstating the case to call Baraka a science fiction writer, he makes it clear in his autobiography that the genre constitutes part of his cultural heritage as a twentieth-century city kid. Growing up in Newark meant listening to the radio and imagining life's possibilities in the terms it provided. The radio, he says, always another school for my mind (26). shows that captured his imagination conjured up adventure and strangeness: Shadow, I Love a Mystery, Inner Sanctum, Escape. last was particularly influential. It broadcast stories by famous writers, stories of fantasy and science fiction by the likes of H. …

"1 + 1 = 3" and Other Dilemmas: Reading Vertigo in "Invisible Man", "My Life in the Bush of Ghosts", and "Song of Solomon"

... the metaphor of the chain of communication picks up the sense of contingency as contiguity, while the question of the link immediately raises the issue of contingency as the indeterminate. (Homi K. Bhabha 188) I won't even talk about the cultural heritage from Africa. (Ralph Ellison, Going to the Territory 66) By representing aporia, dislocation, and caesura through vernacular space, Toni Morrison's Song of Solomon (1977) asserts that Amos Tutuola's My Life in the Bush of Ghosts (1954) and Ralph Ellison's In visible Man (2952) constitute linked gestures toward the diasporic sensibility within which Morrison situates her own work. This strategy of foregrounding aporetic impasse and lapsed rhetorical connections addresses a significant tension in Ellison's work, recuperating an apparent blindness toward African retentions operating at the level of deep structure in his own text. Morrison's revision explores these moments of blindness in Ellison's text and exposes their contours. Relying on black vernacular motifs inspired by Ellison, Morrison's narrative strategy also reveals that, taken together, the three texts chart both individualized and collective evolutions of diaspora consciousness across national and geographic boundaries. These generational shifts reveal sites of neocolonial cultural arrest, rupture, and vi olence, thematized through a network of allusions to ascent, suspension, and rotation. In contemplating these representations as spatiotemporal features of diaspora culture, Song of Solomon constructs African diaspora subjectivity through what I will call an aesthetics of vertigo that reconfigures the of Black space. This usage of the term psychogeography posits, after Lefebvre, that, in the production of social space, foreclosed zones of resistance can be made habitable. (2) Such transgressive spaces are frequently represented through narratives of cultural chaos inscribed as incoherence and vertiginous anxiety, as in both Ellison and Tutuola. Morrison participates in these representations, but claims a route to equilibrium by rewriting vertigo as a liminal site of creative tension that can be better understood in the context of African diaspora cosmologies. These hybrid cosmologies which support her protagonist's acclimation to a vertiginous, diasporic subjectivity are derived primarily from Yoruba and related traditions, including Ifa, Vodoun, and hoodoo, and from archetypal figures within these traditions, particularly Obatala and Eshu. For the purposes of this essay, vertigo is an element in Ellison's and Tutuola's work that for Morrison becomes a vernacular event that reveals a habitable space organized by diasporic cosmologies, in which autopoesis, self-creation, can be realized. All three texts encode vertigo as more than inexplicable instances of perceptual disturbance. Vertigo captures the relationship of the internal experience of the colonized to the colonized environment. As the authors explore the uncharted spaces of diaspora subjectivity, they confront the unarticulated implications of vertigo as a cultural phenomenon. In environments organized by neo-colonialist constructions of race, the protagonists face unavoidable assaults on their humanity, sanity, and cultural coherence. In the aftermath of slavery, Tutuola's nameless protagonist occupies the emblematic position of having no right to describe myself (170). Milkman lack[s] coherence, a coming together of the features into a total self (Song 69). They experience the effects of colonialism and racism as psychological trauma, generally represented as fragmentation or splitting, framed by Du Boisian double-consciousness, as is evident when Tutuola's protagonist later comments, that we left ourselves on the road to beco ming slave and master (171). Because they inhabit places dominated by colonialist hegemonies that confront them with abnormally hostile negations, the protagonists lack spaces in which to redefine and voice themselves. …

On the intrinsic parity of black holes

We investigate the intrinsic parity of black holes. It appears that discrete symmetries require the black hole Hilbert space to be larger than suggested by the usual quantum numbers M (mass), Q (charge) and J (angular momentum). Recent results on black hole production in trans-Planckian scattering lead to gravitational effects which do not decouple from low-energy physics. Dispersion relations incorporating these effects imply that the semi-classical black hole spectrum is similar in parity even and odd channels. This result can be generalized to other discrete and continuous symmetries.

Jamaica Kincaid's Voracious Bodies: Engendering a Carib(bean) Woman

Engaged in a literary tradition and a cultural heritage which remains defiantly patriarchal, Jamaica Kincaid's writing thrives on bringing erasures back to life, to re- placing the lives of women and indigenous cultures as foundational elements of the discursive Caribbean. Her fiction emerges as a voracious poetics, aimed at consuming colonial Caribbean narratives. In Kincaid's 1996 novel, The Autobiography of My Mother, Xuela Richardson is born at the moment her mother, a Carib woman, dies. Xuela laments: (m)y mother died at the moment I was born, and so for my whole life there was nothing standing between myself and eternity; at my back was always a wind (3). This paper examines Kincaid's portrayal of Xuela's self- making as a re-fashioning of that bleak, black space. Kincaid constructs a metaphor of sexual devouring as a response to colonial history's objectifying representation of the Carib people as ravenously sexual and cannibalistic. After the mother's death, Xuela's father abandons her, placing her in the care of the woman who launders his clothes, Ma Eunice. The mother's van(qu)ished Carib body and voice is a marked, compensatory space in which Xuela attempts to transcend the fate she inherits from her mother. Xuela is the receptacle of the mother's life and history, a history that culminates in vanquishment. Without the mother's presence and without her father's presence, Xuela must find out for herself who she is and what her place is in Dominica. At the age of four, she becomes accustomed to seeing her father every fortnight when he comes to Ma Eunice for his clothes. When he does not appear after one fortnight, Xuela asks Where is my father? (6-7). This first utterance in English, a language that Xuela has never heard anyone speak, yet in which she knows how to form a sentence, sets up the novel's argument with history and colonialism. Xuela continues: That the first words I said were in the language of a people I would never like or love is not now a mystery to me; everything in my life, good or bad, to which I am inextricably bound is a source of pain (7). As a child, Xuela can already identify the histories that make up her identity. While at school, in a class with seven boys and herself, she is conscious of the marks that distinguish her from the teacher and the other students:

Dynamic dS/CFT correspondence using the brane cosmology

We explore the dynamic dS/CFT correspondence using the moving domain wall(brane) approach in the brane cosmology. The bulk spacetimes are given by the Schwarzschild-de Sitter (SdS) black hole and the topological-de Sitter (TdS) solutions. We consider the embeddings of (Euclidean) moving domain walls into the (Euclidean) de Sitter spaces. The TdS solution is better to describe the static dS/CFT correspondence than the SdS black hole, while in the dynamic dS/CFT correspondence the SdS solution provides situation better than that of the TdS solution. However, we do not find a desirable cosmological scenario from the SdS black hole space.

Black holes at neutrino telescopes

In scenarios with extra dimensions and TeV-scale quantum gravity, black holes are expected to be produced in the collision of light particles at center-of-mass energies above the fundamental Planck scale with small impact parameters. Black hole production and evaporation may thus be studied in detail at the Large Hadron Collider (LHC). But even before the LHC starts operating, neutrino telescopes such as AMANDA/IceCube, ANTARES, Baikal, and RICE have an opportunity to search for black hole signatures. Black hole production in the scattering of ultrahigh energy cosmic neutrinos on nucleons in the ice or water may initiate cascades and through-going muons with distinct characteristics above the Standard Model rate. In this Letter, we investigate the sensitivity of neutrino telescopes to black hole production and compare it to the one expected at the Pierre Auger Observatory, an air shower array currently under construction, and at the LHC. We find that, already with the currently available data, AMANDA and RICE should be able to place sensible constraints in black hole production parameter space, which are competitive with the present ones from the air shower facilities Fly's Eye and AGASA. In the optimistic case that a ultrahigh energy cosmic neutrino flux significantly higher than the one expected from cosmic ray interactions with the cosmic microwave background radiation is realized in nature, one even has discovery potential for black holes at neutrino telescopes beyond the reach of LHC.

Collider versus cosmic ray sensitivity to black hole production

In scenarios with extra dimensions and TeV-scale quantum gravity, black holes are expected to be produced copiously at center-of-mass energies above the fundamental Planck scale. The Large Hadron Collider (LHC) may thus turn into a factory of black holes, at which their production and evaporation may be studied in detail. But even before the LHC starts operating, the Pierre Auger Observatory for cosmic rays, presently under construction, has an opportunity to search for black hole signatures. Black hole production in the scattering of ultrahigh energy cosmic neutrinos on nucleons in the atmosphere may initiate quasi-horizontal air showers far above the Standard Model rate. In this letter, we compare the sensitivity of LHC and Auger to black hole production by studying their respective reach in black hole production parameter space. Moreover, we present constraints in this parameter space from the non-observation of horizontal showers by the Fly's Eye collaboration. We find that if the ultrahigh energy neutrino flux is at the level expected from cosmic ray interactions with the cosmic microwave background radiation, Auger has only a small window of opportunity to detect black holes before the start of the LHC. If, on the other hand, larger ultrahigh energy neutrino fluxes on the level of the upper limit from ``hidden'' hadronic astrophysical sources are realized in nature, then the first signs of black hole production may be observed at Auger. Moreover, in this case, the Fly's Eye constraints, although more model dependent, turn out to be competitive with other currently available constraints on TeV-scale gravity which are mainly based on interactions associated with Kaluza-Klein gravitons.

EXPLICIT DERIVATION OF THE FLUCTUATION-DISSIPATION RELATION OF THE VACUUM NOISE IN THE N-DIMENSIONAL DE SITTER SPACE–TIME

Motivated by a recent work by Terashima (Phys. Rev.D60, 084001), we revisit the fluctuation-dissipation (FD) relation between the dissipative coefficient of a detector and the vacuum noise of fields in curved space–time. In an explicit manner we show that the dissipative coefficient obtained from classical equations of motion of the detector and the scalar (or Dirac) field satisfies the FD relation associated with the vacuum noise of the field, which demonstrates that Terashima's prescription works properly in the N-dimensional de Sitter space–time. This practice is useful not only to reconfirm the validity of the use of the retarded Green function to evaluate the dissipative coefficient from the classical equations of motion but also to understand why the derivation works properly, which is discussed in connection with previous investigations on the basis of the Kubo–Martin–Schwinger (KMS) condition. Possible application to black hole space–time is also briefly discussed.

Adjoint operators and perturbation theory of black holes

We present a new approach for finding conservation laws in the perturbation theory of black holes which applies for the more general cases of non-Hermitian equations governing the perturbations. The approach is based on a general result which establishes that a covariantly conserved current can be obtained from a solution of any system of homogeneous linear differential equations and a solution of the adjoint system. It is shown that the results obtained from the present approach become essentially the same (with some differences) to those obtained by means of the traditional methods in the simplest black hole geometry corresponding to the Schwarzschild space–time. The future applications of our approach for studying the perturbations of black hole space–times in string theory is discussed.