Evaporation of primordial black holes
NASA Astrophysics Data System (ADS)
Hawking, S. W.
The usual explanation of the isotropy of the universe is that inflation would have smoothed out any inhomogeneities. However, if the universe was initially fractal or in a foam like state, an overall inflation would have left it in the same state. I suggest that the universe did indeed begin with a tangled web of wormholes connecting pairs of black holes but that the inflationary expansion was unstable: wormholes that are slightly smaller correspond to black holes that are hotter than the cosmological background and evaporate away. This picture is supported by calculations with Raphael Bousso of the evaporation of primordial black holes in the s-wave and large N approximations.
Positrons from quantum evaporation of primordial black-holes
NASA Technical Reports Server (NTRS)
Durouchoux, P.; Wallyn, P.; Dubus, G.
1997-01-01
The unconfirmed prediction of quantum evaporation of primordial black holes (PBHs) is considered together with the related unanswered questions of whether PBHs ever existed and whether any could still exist. The behavior of the positrons from PHBs is modeled in relation to three facts. Firstly, the integrated emitted number spectrum of positrons is six to eight times larger than that of photons. Secondly, positrons emitted from PBHs lose energy and annihilate, producing a prominent line at 511 keV which is redshifted by the expansion of the universe. Thirdly, these photons may be detectable in the X-ray and low gamma ray energy ranges. The model predicts a flux which is significantly inferior to the instrument sensitivities of the foreseeable future.
Primordial Black Holes: Observational characteristics of the final evaporation
NASA Astrophysics Data System (ADS)
Ukwatta, T. N.; Stump, D. R.; Linnemann, J. T.; MacGibbon, J. H.; Marinelli, S. S.; Yapici, T.; Tollefson, K.
2016-07-01
Many early universe theories predict the creation of Primordial Black Holes (PBHs). PBHs could have masses ranging from the Planck mass to 105 solar masses or higher depending on the size of the universe at formation. A Black Hole (BH) has a Hawking temperature which is inversely proportional to its mass. Hence a sufficiently small BH will quasi-thermally radiate particles at an ever-increasing rate as emission lowers its mass and raises its temperature. The final moments of this evaporation phase should be explosive and its description is dependent on the particle physics model. In this work we investigate the final few seconds of BH evaporation, using the Standard Model and incorporating the most recent Large Hadron Collider (LHC) results, and provide a new parameterization for the instantaneous emission spectrum. We calculate for the first time energy-dependent PBH burst light curves in the GeV/TeV energy range. Moreover, we explore PBH burst search methods and potential observational PBH burst signatures. We have found a unique signature in the PBH burst light curves that may be detectable by GeV/TeV gamma-ray observatories such as the High Altitude Water Cerenkov (HAWC) observatory. The implications of beyond the Standard Model theories on the PBH burst observational characteristics are also discussed, including potential sensitivity of the instantaneous photon detection rate to a squark threshold in the 5-10 TeV range.
Primordial Black Holes: Observational characteristics of the final evaporation
Ukwatta, T. N.; Stump, D. R.; Linnemann, J. T.; MacGibbon, J. H.; Marinelli, S. S.; Yapici, T.; Tollefson, K.
2016-07-01
For many early universe theories predict the creation of Primordial Black Holes (PBHs). PBHs could have masses ranging from the Planck mass to 105 solar masses or higher depending on the size of the universe at formation. A Black Hole (BH) has a Hawking temperature which is inversely proportional to its mass. Hence a sufficiently small BH will quasi-thermally radiate particles at an ever-increasing rate as emission lowers its mass and raises its temperature. Moreover, the final moments of this evaporation phase should be explosive and its description is dependent on the particle physics model. In this work we investigatemore » the final few seconds of BH evaporation, using the Standard Model and incorporating the most recent Large Hadron Collider (LHC) results, and provide a new parameterization for the instantaneous emission spectrum. We calculate for the first time energy-dependent PBH burst light curves in the GeV/TeV energy range. Moreover, we explore PBH burst search methods and potential observational PBH burst signatures. We have found a unique signature in the PBH burst light curves that may be detectable by GeV/TeV gamma-ray observatories such as the High Altitude Water Cerenkov (HAWC) observatory. Finally, the implications of beyond the Standard Model theories on the PBH burst observational characteristics are also discussed, including potential sensitivity of the instantaneous photon detection rate to a squark threshold in the 5–10 TeV range.« less
Primordial black holes: pair creation, Lorentzian condition, and evaporation.
NASA Astrophysics Data System (ADS)
Bousso, R.; Hawking, S. W.
1999-04-01
The wave function of the universe is usually taken to be a functional of the three-metric on a spacelike section, Σ, which is measured. It is sometimes better, however, to work in the conjugate representation, where the wave function depends on a quantity related to the second fundamental form of Σ. This makes it possible to ensure that Σ is part of a Lorentzian universe by requiring that the argument of the wave function be purely imaginary. The authors demonstrate the advantages of this formalism first in the well-known examples of the nucleation of a de Sitter or a Nariai universe. They then use it to calculate the pair creation rate for submaximal black holes in de Sitter space, which had been thought to vanish semiclassically. They also study the quantum evolution of asymptotically de Sitter black holes. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. The model includes the one-loop effective action in the s-wave and large-N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, the authors find that nearly maximal quantum Schwarzschild-de Sitter black holes antievaporate. However, there is a different perturbative mode that leads to evaporation. They show that this mode will always be excited when a pair of maximal cosmological black holes nucleates.
Search for ultrashort gamma-ray bursts from evaporating primordial black holes
NASA Astrophysics Data System (ADS)
Vereshkov, G. M.; Petkov, V. B.
2015-02-01
Cosmic gamma-ray bursts from evaporating primordial black holes for the evaporation model with relativistic phase transitions have been sought in the data from the Andyrchy extensive air shower (EAS) array. This model predicts ultrashort (≃10-13 s) gamma-ray bursts with the spectrum with the maximum intensities simultaneously at the photon energies of 100 MeV and 100 GeV. Such ultrashort gamma-ray bursts can be detected by EAS arrays located on mountains as EASs with a uniform lateral distribution. A limit on the concentration of evaporating primordial black holes in a local region of the Galaxy for this evaporation model has been obtained from information accumulated during a live time of 4.23 yr.
Search for TeV Gamma Ray Bursts from Evaporating Primordial Black Holes
NASA Astrophysics Data System (ADS)
Xu, Chun-xian; He, Hui-lin; Chen, Yong-zhong; He, Hui-hai; Li, Hui-dong; Zhang, Yong; Jiang, Yin-lin
1998-08-01
Data taken with ACT2 and ACT3 between 1995 and 1997 are used to search for 0.1 s bursts of TeV gamma ray from evaporating primordial black holes (PBHs). There is no evidence for such bursts in the dataset. Using the result, the upper limit of 3×108pc-3yr-1 on the rate-density of evaporating PBHs is set in the vicinity of the solar system at a 99% confidence level.
NASA Astrophysics Data System (ADS)
Belyanin, A. A.; Kocharovsky, V. V.; Kocharovsky, Vl. V.
2001-04-01
Universal observational feature of microscopic primordial black holes is the Hawking emission which is believed to occur in the regime of noninteracting quark-gluon jets and their products. Then, stringent upper limit on the number density of primordial black holes seems to rule out the possibility of their discovery in the near future. Contrary to this widely accepted opinion, we show that, when the black-hole temperature exceeds 10 GeV, the charged particle outflow from a black hole becomes plasma and the magnetohydrodynamical regime of expansion can be realized. In this case, the kinetic energy of ejected particles can be converted into the 0.1-1 MeV γ-rays due to the synchrotron radiation and electromagnetic cascade in the close-to-equipartition turbulent magnetic field. Also, the cascade leads to the significant increase of photon flux in the sub-GeV range. As a result, a black hole with mass below 1012 g becomes a transient γ-ray source with luminosity growing according to the explosive-type law. We show that up to several per cent of the gamma-ray bursts detected by BATSE can be associated with evaporating black holes with temperature exceeding ~1 TeV and masses below 1010 g, located at distances within ~1 pc from the Earth. .
A new search for primordial black hole evaporations using the Whipple gamma-ray telescope
NASA Astrophysics Data System (ADS)
Linton, E. T.; Atkins, R. W.; Badran, H. M.; Blaylock, G.; Boyle, P. J.; Buckley, J. H.; Byrum, K. L.; Carter-Lewis, D. A.; Celik, O.; Chow, Y. C. K.; Cogan, P.; Daniel, M. K.; Dowdall, C.; Falcone, A. D.; Fegan, D. J.; Fegan, S. J.; Finley, J. P.; Fortin, P.; Guiterrez, K. J.; Hall, J.; Hanna, D.; Holder, J.; Horan, D.; Hughes, S. B.; Humensky, T. B.; Jung, I.; Kenny, G. E.; Kertzman, M.; Kieda, D. B.; Kildea, J.; Knapp, J.; Krawczynski, H.; Lang, M. J.; LeBohec, S.; Maier, G.; Moriarty, P.; Ong, R. A.; Perkins, J. S.; Pizlo, F.; Pohl, M.; Quinn, J.; Ragan, K.; Rebillot, P. F.; Reynolds, P. T.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Valcarcel, L.; Wakely, S. P.; Weekes, T. C.; White, R. J.
2006-01-01
Stephen Hawking's prediction that black holes should radiate like black bodies has several important consequences, including the possibility of the detection of small (~1015 g) black holes created in the very early universe. The detection of such primordial black holes (PBHs) would be an important discovery, not only confirming Hawking's theory, but also providing valuable insights into the history of the early universe. A search through 5.5 years of archival data from the Whipple Atmospheric Cerenkov Telescope is made for TeV gamma-ray bursts on 1, 3, and 5 s timescales. On the basis of a null result from this direct search for PBH evaporations, an upper limit of 1.08 × 106 pc-3 yr-1 (99% CL) is set on the PBH evaporation rate in the local region of the galaxy, assuming the Standard Model of particle physics. This is more than a factor of two better than the previous limit at this energy range and includes longer timescales than have previously been explored. Comparison of this result with previous limits on the fraction of the critical density comprised by PBHs, Ωpbh, depends strongly on assumptions made about PBH clustering; in models predicting strong PBH clustering, the limit in this work could be as many as ten orders of magnitude more stringently than those set by diffuse MeV gamma-ray observations.
Milagro limits and HAWC sensitivity for the rate-density of evaporating primordial black holes
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; H. A. Ayala Solares; et al
2015-04-01
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ~ 5.0 × 10¹⁴ g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV – TeV energy range. The Milagro high energy observatory, which operated from 2000 tomore » 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.« less
Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes
NASA Astrophysics Data System (ADS)
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Aune, T.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carramiñana, A.; Castillo, M.; Christopher, G. E.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hays, E.; Hoffman, C. M.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kolterman, B. E.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-GarcIa, R.; MacGibbon, J. H.; Marinelli, A.; Marinelli, S. S.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Mincer, A. I.; Miranda-Romagnoli, P.; Moreno, E.; Morgan, T.; Mostafá, M.; Nellen, L.; Nemethy, P.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Rivière, C.; Rosa-González, D.; Ruiz-Velasco, E.; Ryan, J.; Salazar, H.; Salesa, F.; Sandoval, A.; Saz Parkinson, P. M.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Stump, D.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Vasileiou, V.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Williams, D. A.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.
2015-04-01
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ∼5.0 × 1014 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV-TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.
Milagro limits and HAWC sensitivity for the rate-density of evaporating primordial black holes
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; H. A. Ayala Solares; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Gonzalez, J. Becerra; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carraminana, A.; Castillo, M.; Christopher, G. E.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hays, E.; Hoffman, C. M.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kolterman, B. E.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; Vargas, H. Leon; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-GarcIa, R.; MacGibbon, J. H.; Marinelli, A.; Marinelli, S. S.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; J. A.J. Matthews; McEnery, J.; Mendoza Torres, E.; Mincer, A. I.; Miranda-Romagnoli, P.; Moreno, E.; Morgan, T.; Mostafa, M.; Nellen, L.; Nemethy, P.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Perez-Perez, E. G.; Pretz, J.; Riviere, C.; Rosa-Gonzalez, D.; Ruiz-Velasco, E.; Ryan, J.; Salazar, H.; Salesa, F.; Sandoval, A.; Saz Parkinson, P. M.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Stump, D.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Vasileiou, V.; Villasenor, L.; Weisgarber, T.; Westerhoff, S.; Williams, D. A.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.
2015-04-01
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ~ 5.0 × 10¹⁴ g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV – TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.
Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes
NASA Technical Reports Server (NTRS)
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Rosales, M. Bonilla; Braun, J.; Hays, E.
2014-01-01
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of approx.5.0 x 10(exp 14) g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV-TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.
Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes
NASA Technical Reports Server (NTRS)
Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B.T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; Ayala Solares, H. A.; Hays, E.
2014-01-01
Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of approximately 5.0 x 10 (sup 14) grams should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the gigaelectronvolt - teraelectronvolt energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90 percent duty cycle and sensitivity up to 100 teraelectronvolt gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.
Mechanism of quasistabilization of primordial black holes
NASA Astrophysics Data System (ADS)
Torres, R.
2013-06-01
It is argued that primordial black holes with initial masses satisfying M<1015g, instead of having explode, might currently be in a quasistable phase contributing to a tiny fraction of the measured dark matter. This statement is based on a computation of black hole evaporation in which energy conservation is taken into account that shows that the backreaction to Hawking radiation favors the quasistabilization of the black hole. The result is specifically shown for general spherically symmetric quantum black holes described by an effective metric independently of the specific framework from which it is derived. The quintessential primordial black hole is fully analyzed as an example.
Clusters of primordial black holes and reionization problem
Belotsky, K. M. Kirillov, A. A. Rubin, S. G.
2015-05-15
Clusters of primordial black holes may cause the formation of quasars in the early Universe. In turn, radiation from these quasars may lead to the reionization of the Universe. However, the evaporation of primordial black holes via Hawking’s mechanism may also contribute to the ionization of matter. The possibility of matter ionization via the evaporation of primordial black holes with allowance for existing constraints on their density is discussed. The contribution to ionization from the evaporation of primordial black holes characterized by their preset mass spectrum can roughly be estimated at about 10{sup −3}.
Nonthermal WIMPs and primordial black holes
NASA Astrophysics Data System (ADS)
Georg, Julian; Şengör, Gizem; Watson, Scott
2016-06-01
Nonthermal histories for the early universe have received notable attention as they are a rich source of phenomenology, while also being well motivated by top-down approaches to beyond the Standard Model physics. The early (pre-big bang nucleosynthesis) matter phase in these models leads to enhanced growth of density perturbations on sub-Hubble scales. Here, we consider whether primordial black hole formation associated with the enhanced growth is in conflict with existing observations. Such constraints depend on the tilt of the primordial power spectrum, and we find that nonthermal histories are tightly constrained in the case of a significantly blue spectrum. Alternatively, if dark matter is taken to be of nonthermal origin, we can restrict the primordial power spectrum on scales inaccessible to cosmic microwave background and large scale structure observations. We establish constraints for a wide range of scalar masses (reheat temperatures) with the most stringent bounds resulting from the formation of 1015 g black holes. These black holes would be evaporating today and are constrained by FERMI observations. We also consider whether the breakdown of the coherence of the scalar oscillations on subhorizon scales can lead to a Jean's pressure preventing black hole formation and relaxing our constraints. Our main conclusion is that primordial black hole constraints, combined with existing constraints on nonthermal weakly interacting massive particles, favor a primordial spectrum closer to scale invariance or a red tilted spectrum.
Grand unification scale primordial black holes: consequences and constraints.
Anantua, Richard; Easther, Richard; Giblin, John T
2009-09-11
A population of very light primordial black holes which evaporate before nucleosynthesis begins is unconstrained unless the decaying black holes leave stable relics. We show that gravitons Hawking radiated from these black holes would source a substantial stochastic background of high frequency gravititational waves (10(12) Hz or more) in the present Universe. These black holes may lead to a transient period of matter-dominated expansion. In this case the primordial Universe could be temporarily dominated by large clusters of "Hawking stars" and the resulting gravitational wave spectrum is independent of the initial number density of primordial black holes. PMID:19792364
Probability for primordial black holes
NASA Astrophysics Data System (ADS)
Bousso, R.; Hawking, S. W.
1995-11-01
We consider two quantum cosmological models with a massive scalar field: an ordinary Friedmann universe and a universe containing primordial black holes. For both models we discuss the complex solutions to the Euclidean Einstein equations. Using the probability measure obtained from the Hartle-Hawking no-boundary proposal we find that the only unsuppressed black holes start at the Planck size but can grow with the horizon scale during the roll down of the scalar field to the minimum.
Gamma rays and energetic particles from primordial black holes
NASA Technical Reports Server (NTRS)
Halzen, F.; Zas, E.; Macgibbon, J. H.; Weekes, T. C.
1991-01-01
The standard model of quarks and leptons is used to discuss the signatures of black-hole evaporations. A firm bound on the primordial black hole abundance is obtained from MeV data. It is argued that the MeV bound can be improved by exploiting the new generation of TeV and PeV telescopes.
Gamma -bursts by primordial Black Holes
NASA Astrophysics Data System (ADS)
Gaina, Alex
Gamma-burts may arise as a result of quantum generation of photons (as well as neutrinos, gravitons, electrons) by Primordial Black Holes (PBH's) of mass 5-7 x 10^14 g (Hawking: Nature, Volume 248, Issue 5443, pp. 30-31, 1974,Communications in Mathematical Physics, Volume 43, Issue 3, pp.199-220; Page:Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole, Phys. Rev. D 13, 198, 1976,Physical Review D - Particles and Fields, 3rd Series, vol. 14, Dec. 15, 1976, p. 3260-327, Particle emission rates from a black hole. III. Charged leptons from a nonrotating hole Phys. Rev. D 16, 2402 Published 15 October 1977; Jane Mac Gibbon, Quark- and gluon-jet emission from primordial black holes. II. The emission over the black-hole lifetime Phys. Rev. D 44, 376 - Published 15 July 1991, J.H. MacGibbon & B.J. Carr,Astrophysical Journal, Part 1, vol. 371, April 20, 1991, p. 447-469 ). Another way of the Gamma-rays production by highly rotating PBH's results from the bomb-like accumulation of mass bosons on superradiative bound levels, which I have called Bose instability in Black Holes (Ternov et al.Soviet Physics Journal, Volume 21, Issue 9, pp.1200-1204 1978; Detweiler: Physical Review D (Particles and Fields), Volume 22, Issue 10, 15 November 1980, pp.2323-2326 1980; Gaina and Ternov: Soviet Astronomy Letters, vol. 12, Nov.-Dec. 1986, p. 394-396; Gaina: Soviet Astronomy Letters, Vol.15, NO.3/MAY,JUN, P. 243, 1989,Astronomical and Astrophysical Transactions, vol. 10, Issue 2, pp.111-112, 1996,Bulletin Astronomique de Belgrade, No. 153, p. 29 - 34 ). The only type of black Holes which is still undiscovered is just the primordial Black Holes type. Is this a technical problem related wuith the sensitivity of Gamma-detectors or this is rather a problem of unfinalized of the quantum mechanical treatment of the Black Holes evaporation? Is this a problem related with inexactitudes of measurements of the Hubble constant or the primordial black
Unification models with reheating via primordial black holes
NASA Astrophysics Data System (ADS)
Hidalgo, J. C.; Ureña-López, L. Arturo; Liddle, Andrew R.
2012-02-01
We study the possibility of reheating the universe through the evaporation of primordial black holes created at the end of inflation. This is shown to allow for the unification of inflation with dark matter or dark energy, or both, under the dynamics of a single scalar field. We determine the necessary conditions to recover the standard big bang by the time of nucleosynthesis after reheating through black holes.
The primordial black hole mass range
NASA Astrophysics Data System (ADS)
Frampton, Paul H.
2016-04-01
We investigate Primordial Black Hole (PBH) formation by which we mean black holes produced in the early Universe during radiation domination. After discussing the range of PBH mass permitted in the original mechanism of Carr and Hawking, hybrid inflation with parametric resonance is presented as an existence theorem for PBHs of arbitrary mass. As proposed in arXiv:1510.00400, PBHs with many solar masses can provide a solution to the dark matter problem in galaxies. PBHs can also explain dark matter observed in clusters and suggest a primordial origin for Supermassive Black Holes (SMBHs) in galactic cores.
Accretion of radiation and rotating primordial black holes
NASA Astrophysics Data System (ADS)
Mahapatra, S.; Nayak, B.
2016-02-01
We consider rotating primordial black holes (PBHs) and study the effect of accretion of radiation in the radiation-dominated era. The central part of our analysis deals with the role of the angular momentum parameter on the evolution of PBHs. We find that both the accretion and evaporation rates decrease with an increase in the angular momentum parameter, but the rate of evaporation decreases more rapidly than the rate of accretion. This shows that the evaporation time of PBHs is prolonged with an increase in the angular momentum parameter. We also note that the lifetime of rotating PBHs increases with an increase in the accretion efficiency of radiation as in the case of nonrotating PBHs.
Primordial black holes as all dark matter
Frampton, Paul H.; Kawasaki, Masahiro; Takahashi, Fuminobu; Yanagida, Tsutomu T. E-mail: kawasaki@icrr.u-tokyo.ac.jp E-mail: tsutomu.tyanagida@ipmu.jp
2010-04-01
We argue that a primordial black hole is a natural and unique candidate for all dark matter. We show that, in a smooth-hybrid new double inflation model, a right amount of the primordial black holes, with a sharply-defined mass, can be produced at the end of the smooth-hybrid regime, through preheating. We first consider masses < 10{sup −7}M{sub s}un which are allowed by all the previous constraints. We next discuss much heavier mass 10{sup 5}M{sub s}un hinted at by entropy, and galactic size evolution, arguments. Effects on the running of the scalar spectral index are computed.
Effect of Accretion of Phantom Energy on Initial Mass of a Primordial Black Hole
NASA Astrophysics Data System (ADS)
Naz, Sumaira; Qadir, Asghar
2012-03-01
Hawking had shown that black holes radiate with a temperature inversely proportional to their mass, thereby losing energy and hence mass. For sufficiently small masses (less than 1015 g) the black hole would evaporate today and hence has a "life" equal to the present age of the universe. One explanation of the observed acceleration of the universe is by phantom energy. In 2010 Jamil and Qadir have showed that this energy enhances the rate of evaporation. Thus, to have a primordial black hole evaporating today, its initial mass should be larger than 1015 g or the primordial black holes of mass less than 1015 g should evaporate earlier. In fact, it was claimed that the black holes would be ten orders of magnitude larger! This effect is revisited and its dependence on the value of equation of state parameter is studied. It is found that the effect of phantom energy for the 1015 g black hole is negligible but for a 1022 g black hole would be significant. In that case, though, the black hole would not be now exploding. The mass at which the effect of phantom energy equals the effect of Hawking radiation has been called the transition mass. The transition mass has been discussed and the correction term in the lifetime for primordial black holes is computed.
The double formation of primordial black holes
Nakama, Tomohiro
2014-10-01
Primordial black holes (PBHs) are a useful tool in cosmology to probe primordial inhomogeneities on small scales that reenter the Hubble radius during the radiation dominated epoch. In this paper, a phenomenon we call the double formation of PBHs, described below, is explored. Suppose there exists a highly perturbed region which will collapse to form a PBH after the horizon crossing of this region, and farther that this region is superposed on a perturbed region of a much larger scale, which also collapses upon its reentry. One then expects the collapse of the central smaller region at the time of the crossing of this region, followed by another collapse of the larger perturbation at the time of its respective crossing. The smaller PBH, formed earlier, should be swallowed in the second collapse leading to a single larger PBH as the final state. This paper reports the first direct numerical confirmation of such double PBH formation. Related to this, we also discuss the effects of high-frequency modes on the formation of PBHs, which turn out to facilitate the formation of PBHs, thereby potentially increasing the abundance of PBHs by several orders of magnitude.
Hydrodynamics of primordial black hole formation
NASA Technical Reports Server (NTRS)
Nadezhin, D. K.; Novikov, I. D.; Polnarev, A. G.
1979-01-01
The hydrodynamic picture of the formation of primordial black holes (PBH) at the early stages of expansion of the Universe is considered. It is assumed that close to singularity, expansion occurs in a quasi-isotropic way. Using an EVM, a spherically symmetrical nonlinear problem of the evolution of primary strong deviation from the Fridman solution was solved. What these deviations must be, so that the formation of PBH occurred was clarified. Attention was devoted to the role of pressure gradients. It is pointed out that at the moment of formation of PBH, only a small part of matter enters into it, primarily the component of perturbation. It is also pointed out that at this moment, the mass of PBH essentially is smaller than the mass considered within the cosmic horizon. The possibility of changing the mass of the PBH as a result of accretion is analyzed.
Cosmic rays from primordial black holes
NASA Technical Reports Server (NTRS)
Macgibbon, Jane H.; Carr, B. J.
1991-01-01
The quark and gluon emission from primordial black holes (PBHs) which may have formed from initial density perturbations or phase transitions in the early universe are investigated. If the PBHs formed from scale-invariant initial density perturbations in the radiation dominated era, it is found that the emission can explain or contribute significantly to the extragalactic photon and interstellar cosmic-ray electron, positron, and antiproton spectra around 0.1-1 GeV. In particular, the PBH emission strongly resembles the cosmic-ray gamma-ray spectrum between 50 and 170 MeV. The upper limits on the PBH density today from the gamma-ray, e(+), e(-), and antiproton data are comparable, provided that the PBHs cluster to the same degree as the other matter in the Galactic halo.
Transient pulses from exploding primordial black holes as a signature of an extra dimension
NASA Astrophysics Data System (ADS)
Kavic, Michael; Simonetti, John H.; Cutchin, Sean E.; Ellingson, Steven W.; Patterson, Cameron D.
2008-11-01
An evaporating black hole in the presence of an extra spatial dimension would undergo an explosive phase of evaporation. We show that such an event, involving a primordial black hole, can produce a detectable, distinguishable electromagnetic pulse, signaling the existence of an extra dimension of size L~10-18-10-20 m. We derive a generic relationship between the Lorentz factor of a pulse-producing 'fireball' and the TeV energy scale. For an ordinary toroidally compactified extra dimension, transient radio-pulse searches probe the electroweak energy scale (~0.1 TeV), enabling comparison with the Large Hadron Collider.
Primordial black holes as a novel probe of primordial gravitational waves. II. Detailed analysis
NASA Astrophysics Data System (ADS)
Nakama, Tomohiro; Suyama, Teruaki
2016-08-01
Recently we have proposed a novel method to probe primordial gravitational waves from upper bounds on the abundance of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations generated in the early Universe is fairly large, they induce substantial scalar perturbations due to their second-order effects. If these induced scalar perturbations are too large when they reenter the horizon, then PBHs are overproduced, their abundance exceeding observational upper limits. That is, primordial tensor perturbations on superhorizon scales can be constrained from the absence of PBHs. In our recent paper we have only shown simple estimations of these new constraints, and hence in this paper, we present detailed derivations, solving the Einstein equations for scalar perturbations induced at second order in tensor perturbations. We also derive an approximate formula for the probability density function of induced density perturbations, necessary to relate the abundance of PBHs to the primordial tensor power spectrum, assuming primordial tensor perturbations follow Gaussian distributions. Our new upper bounds from PBHs are compared with other existing bounds obtained from big bang nucleosynthesis, cosmic microwave background, LIGO/Virgo and pulsar timing arrays.
Unified model of primordial black holes and dark matter formation
NASA Astrophysics Data System (ADS)
Grobov, A. V.; Dmitriev, A. E.; Dokuchaev, V. I.; Rubin, S. G.
2016-02-01
We propose a unified model of primordial black holes and soliton dark matter formation. Dynamic of spherically symmetric clumps of scalar field is considered in Newtonian approximation. The formation of hidden mass of the Universe is discussed. Numerical solution of the system of interacting scalar and gravitational fields is used to obtain the mass of a clumps.
On the Density of Primordial Black Holes in the Galactic Halo
NASA Astrophysics Data System (ADS)
Wright, Edward L.
1996-03-01
Calculations of the rate of local primordial black hole (PBH) explosions often assume that the PBHs can be highly concentrated into galaxies, thereby weakening the Page-Hawking limit on the cosmological density of PBHs. But if the PBHs are concentrated by a factor exceeding c/(H_{0 }R0) 4 x 10 , where R_{0 }= 8.5 kpc is the scale of the Milky Way, then the steady emission from the PBHs in the halo will produce an anisotropic high-latitude diffuse gamma-ray intensity larger than the observed anisotropy. This provides a limit on the rate density of evaporating PBHs of 0.4 pc -3 yr -1, which is more than 6 orders of magnitude lower than recent experimental limits. However, the weak observed anisotropic high-latitude diffuse gamma-ray intensity is consistent with the idea that the dark matter that closes the universe is Planck mass remnants of evaporated black holes.
Baryogenesis in extended inflation. 2: Baryogenesis via primordial black holes
NASA Technical Reports Server (NTRS)
Barrow, John D.; Copeland, Edmund J.; Kolb, Edward W.; Liddle, Andrew R.
1990-01-01
Baryogenesis at the end of extended inflation is studied. Extended inflation is brought to an end by the collisions of bubble walls surrounding regions of true vacuum, a process which produces particles well out of thermal equilibrium. The possibility that the wall collisions may provide a significant density of primordial black holes is considered and their possible role in generating a baryon asymmetry is examined.
Black hole evaporation rates without spacetime.
Braunstein, Samuel L; Patra, Manas K
2011-08-12
Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson's 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem. PMID:21902381
Calculating the mass fraction of primordial black holes
Young, Sam; Byrnes, Christian T.; Sasaki, Misao E-mail: ctb22@sussex.ac.uk
2014-07-01
We reinspect the calculation for the mass fraction of primordial black holes (PBHs) which are formed from primordial perturbations, finding that performing the calculation using the comoving curvature perturbation R{sub c} in the standard way vastly overestimates the number of PBHs, by many orders of magnitude. This is because PBHs form shortly after horizon entry, meaning modes significantly larger than the PBH are unobservable and should not affect whether a PBH forms or not—this important effect is not taken into account by smoothing the distribution in the standard fashion. We discuss alternative methods and argue that the density contrast, Δ, should be used instead as super-horizon modes are damped by a factor k{sup 2}. We make a comparison between using a Press-Schechter approach and peaks theory, finding that the two are in close agreement in the region of interest. We also investigate the effect of varying the spectral index, and the running of the spectral index, on the abundance of primordial black holes.
Dark matter density spikes around primordial black holes
NASA Astrophysics Data System (ADS)
Eroshenko, Yu. N.
2016-06-01
We show that density spikes begin to form from dark matter particles around primordial black holes immediately after their formation at the radiation-dominated cosmological stage. This stems from the fact that in the thermal velocity distribution of particles there are particles with low velocities that remain in finite orbits around black holes and are not involved in the cosmological expansion. The accumulation of such particles near black holes gives rise to density spikes. These spikes are considerably denser than those that are formed later by the mechanism of secondary accretion. The density spikes must be bright gamma-ray sources. Comparison of the calculated signal from particle annihilation with the Fermi-LAT data constrains the present-day cosmological density parameter for primordial black holes with masses M BH ≥ 10-8 M ⊙ from above by values from ΩBH ≤ 1 to ΩBH ≤ 10-8, depending on MBH. These constraints are several orders of magnitude more stringent than other known constraints.
Do evaporating black holes form photospheres?
NASA Astrophysics Data System (ADS)
MacGibbon, Jane H.; Carr, B. J.; Page, Don N.
2008-09-01
Several authors, most notably Heckler, have claimed that the observable Hawking emission from a microscopic black hole is significantly modified by the formation of a photosphere around the black hole due to QED or QCD interactions between the emitted particles. In this paper we analyze these claims and identify a number of physical and geometrical effects which invalidate these scenarios. We point out two key problems. First, the interacting particles must be causally connected to interact, and this condition is satisfied by only a small fraction of the emitted particles close to the black hole. Second, a scattered particle requires a distance ˜E/me2 for completing each bremsstrahlung interaction, with the consequence that it is improbable for there to be more than one complete bremsstrahlung interaction per particle near the black hole. These two effects have not been included in previous analyses. We conclude that the emitted particles do not interact sufficiently to form a QED photosphere. Similar arguments apply in the QCD case and prevent a QCD photosphere (chromosphere) from developing when the black hole temperature is much greater than ΛQCD, the threshold for QCD particle emission. Additional QCD phenomenological arguments rule out the development of a chromosphere around black hole temperatures of order ΛQCD. In all cases, the observational signatures of a cosmic or Galactic halo background of primordial black holes or an individual black hole remain essentially those of the standard Hawking model, with little change to the detection probability. We also consider the possibility, as proposed by Belyanin et al. and D. Cline et al., that plasma interactions between the emitted particles form a photosphere, and we conclude that this scenario too is not supported.
Formation and evaporation of nonsingular black holes.
Hayward, Sean A
2006-01-27
Regular (nonsingular) space-times are given that describe the formation of a (locally defined) black hole from an initial vacuum region, its quiescence as a static region, and its subsequent evaporation to a vacuum region. The static region is Bardeen-like, supported by finite density and pressures, vanishing rapidly at large radius and behaving as a cosmological constant at small radius. The dynamic regions are Vaidya-like, with ingoing radiation of positive-energy flux during collapse and negative-energy flux during evaporation, the latter balanced by outgoing radiation of positive-energy flux and a surface pressure at a pair creation surface. The black hole consists of a compact space-time region of trapped surfaces, with inner and outer boundaries that join circularly as a single smooth trapping horizon. PMID:16486679
Running-mass inflation model and primordial black holes
Drees, Manuel; Erfani, Encieh E-mail: erfani@th.physik.uni-bonn.de
2011-04-01
We revisit the question whether the running-mass inflation model allows the formation of Primordial Black Holes (PBHs) that are sufficiently long-lived to serve as candidates for Dark Matter. We incorporate recent cosmological data, including the WMAP 7-year results. Moreover, we include ''the running of the running'' of the spectral index of the power spectrum, as well as the renormalization group ''running of the running'' of the inflaton mass term. Our analysis indicates that formation of sufficiently heavy, and hence long-lived, PBHs still remains possible in this scenario. As a by-product, we show that the additional term in the inflaton potential still does not allow significant negative running of the spectral index.
Axion inflation with gauge field production and primordial black holes
NASA Astrophysics Data System (ADS)
Bugaev, Edgar; Klimai, Peter
2014-11-01
We study the process of primordial black hole (PBH) formation at the beginning of the radiation era for the cosmological scenario in which the inflaton is a pseudo-Nambu-Goldstone boson (axion) and there is a coupling of the inflaton with some gauge field. In this model inflation is accompanied by the gauge quanta production, and a strong rise of the curvature power spectrum amplitude at small scales (along with non-Gaussianity) is predicted. We show that data on PBH searches can be used for a derivation of essential constraints on the model parameters in such an axion inflation scenario. We compare our numerical results with the similar results published earlier, in the work [A. Linde, S. Mooij, and E. Pajer, Phys. Rev. D 87, 103506 (2013)].
Search for Primordial Black Holes with the Whipple Atmospheric Cerenkov Telescope
NASA Astrophysics Data System (ADS)
Linton, Eric
2005-04-01
Stephen Hawking's prediction that black holes should radiate like black bodies has several important consequences, including the possibility for the detection of small (˜10^15 g) black holes created in the very early universe. The detection of such primordial black holes (PBHs) would not only validate Hawking's theory, but would provide useful insights into the history of the early universe. A search through 5.5 years of archival data from the Whipple Atmospheric Cerenkov Telescope was made for TeV gamma-ray bursts on 1 s, 3 s, and 5 s timescales. Based on a null result, an upper-limit on the evaporation rate of PBHs of 2.69 x10^6 pc-3 yr^- 1 (99% CL) was made, assuming the Standard Model of particle physics. When combined with the results of an earlier search through Whipple data, this limit was lowered to 1.33 x10^6 pc-3 yr-1, which is nearly a factor of 2 better than the previous limit at this energy range.
Black hole evaporation with separated fermions.
Han, Tao; Kribs, Graham D; McElrath, Bob
2003-01-24
In models with a low quantum gravity scale, fast proton decay can be avoided by localizing quarks and leptons to separated positions in an extra 1/TeV sized dimension with gauge and Higgs fields living throughout. Black holes with masses of the order of the quantum gravity scale are therefore expected to evaporate nonuniversally, preferentially radiating directly into quarks or leptons but not both. Should black holes be copiously produced at a future hadron collider, we find the ratio of final state jets to charged leptons to photons is 113:8:1, which differs from previous analyses that assumed all standard model fields live at the same point in the extra dimensional space. PMID:12570482
Investigation of Primordial Black Hole Bursts Using Interplanetary Network Gamma-ray Bursts
NASA Astrophysics Data System (ADS)
Ukwatta, T. N.; Hurley, K.; MacGibbon, J. H.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Pal'shin, V. D.; Goldsten, J.; Boynton, W.; Kozyrev, A. S.; Rau, A.; von Kienlin, A.; Zhang, X.; Connaughton, V.; Yamaoka, K.; Ohno, M.; Ohmori, N.; Feroci, M.; Frontera, F.; Guidorzi, C.; Cline, T.; Gehrels, N.; Krimm, H. A.; McTiernan, J.
2016-07-01
The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating primordial black holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the distance to GRBs using detections from widely separated, non-imaging spacecraft. This method can determine the actual distance to the burst if it is local. We applied this method to constrain distances to a sample of 36 short-duration GRBs detected by the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 1013–1018 cm (7–105 au) range, which are consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Assuming that these bursts are real PBH events, we estimate lower limits on the PBH burst evaporation rate in the solar neighborhood.
Investigation of primordial black hole bursts using interplanetary network gamma-ray bursts
Ukwatta, Tilan Niranjan; Hurley, Kevin; MacGibbon, Jane H.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Pal'Shin, V. D.; Goldsten, J.; Boynton, W.; et al
2016-07-25
The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating primordial black holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the distance to GRBs using detections from widely separated, non-imaging spacecraft. This method can determine the actual distance to the burst if it is local. We applied this method to constrain distances to a sample of 36 short-duration GRBs detected bymore » the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 1013–1018 cm (7–105 au) range, which are consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Furthermore, assuming that these bursts are real PBH events, we estimate lower limits on the PBH burst evaporation rate in the solar neighborhood.« less
Primordial black holes under the double inflationary power spectrum
NASA Astrophysics Data System (ADS)
Kim, Hee Il
2000-09-01
Recently, it has been shown that the primordial black holes (PBHs) produced by near critical collapse in the expanding universe have a scaling mass relation similar to that of black holes produced in asymptotically flat spacetime. Distinct from PBHs formed with a mass about the size of the horizon mass (type I), the PBHs with the scaling relation (type II) can be created with a range of masses at a given formation time. In general, only the case in which the PBH formation is concentrated at one epoch has been considered. However, it is expected that PBH formation is possible over a broad range of epochs if the density fluctuation has a rather large amplitude and smooth scale dependence. In this paper, we study the PBH formation for both types assuming the power spectrum of double inflationary models in which the small scale fluctuations could have large amplitudes independent of the CMBR anisotropy. The mass spectrum of type II PBHs is newly constructed without limiting the PBH formation period. The double inflationary power spectrum is assumed to be of double simple power law which are smoothly connected. Under the assumed power spectrum, the accumulation of small PBHs formed at later times is important and the mass range is significantly broadened for both types. The PBH mass spectra are far smoother than the observed MACHO spectrum due to our assumption of a smooth spectrum. In order to fit the observation, a more spiky spectrum is required.
(Anti-)evaporation of Schwarzschild-de Sitter black holes
NASA Astrophysics Data System (ADS)
Bousso, Raphael; Hawking, Stephen W.
1998-02-01
We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evaporate. However, there is a different perturbative mode that leads to evaporation. We show that this mode will always be excited when a pair of cosmological holes nucleates.
Modelling the evaporation of nonsingular black holes
NASA Astrophysics Data System (ADS)
Taves, Tim; Kunstatter, Gabor
2014-12-01
We present a model for studying the formation and evaporation of nonsingular (quantum corrected) black holes. The model is based on a generalized form of the dimensionally reduced, spherically symmetric Einstein-Hilbert action and includes a suitably generalized Polyakov action to provide a mechanism for radiation backreaction. The equations of motion describing self-gravitating scalar field collapse are derived in local form both in null co-ordinates and in Painleve-Gullstrand (flat slice) co-ordinates. They provide the starting point for numerical studies of complete spacetimes containing dynamical horizons that bound a compact trapped region. Such spacetimes have been proposed in the past as solutions to the information loss problem because they possess neither an event horizon nor a singularity. Since the equations of motion in our model are derived from a diffeomorphism invariant action they preserve the constraint algebra and the resulting energy momentum tensor is manifestly conserved.
Primordial black holes formation from particle production during inflation
NASA Astrophysics Data System (ADS)
Erfani, Encieh
2016-04-01
We study the possibility that particle production during inflation can source the required power spectrum for dark matter (DM) primordial black holes (PBH) formation. We consider the scalar and the gauge quanta production in inflation models, where in the latter case, we focus in two sectors: inflaton coupled i) directly and ii) gravitationally to a U(1) gauge field. We do not assume any specific potential for the inflaton field. Hence, in the gauge production case, in a model independent way we show that the non-production of DM PBHs puts stronger upper bound on the particle production parameter. Our analysis show that this bound is more stringent than the bounds from the bispectrum and the tensor-to-scalar ratio derived by gauge production in these models. In the scenario where the inflaton field coupled to a scalar field, we put an upper bound on the amplitude of the generated scalar power spectrum by non-production of PBHs. As a by-product we also show that the required scalar power spectrum for PBHs formation is lower when the density perturbations are non-Gaussian in comparison to the Gaussian density perturbations.
Primordial black holes in non-Gaussian regimes
Young, Sam; Byrnes, Christian T. E-mail: ctb22@sussex.ac.uk
2013-08-01
Primordial black holes (PBHs) can form in the early Universe from the collapse of rare, large density fluctuations. They have never been observed, but this fact is enough to constrain the amplitude of fluctuations on very small scales which cannot be otherwise probed. Because PBHs form only in very rare large fluctuations, the number of PBHs formed is extremely sensitive to changes in the shape of the tail of the fluctuation distribution — which depends on the amount of non-Gaussianity present. We first study how local non-Gaussianity of arbitrary size up to fifth order affects the abundance and constraints from PBHs, finding that they depend strongly on even small amounts of non-Gaussianity and the upper bound on the allowed amplitude of the power spectrum can vary by several orders of magnitude. The sign of the non-linearity parameters (f{sub NL}, g{sub NL}, etc.) are particularly important. We also study the abundance and constraints from PBHs in the curvaton scenario, in which case the complete non-linear probability distribution is known, and find that truncating to any given order (i.e. to order f{sub NL} or g{sub NL}, etc.) does not give accurate results.
Probing loop quantum gravity with evaporating black holes.
Barrau, A; Cailleteau, T; Cao, X; Diaz-Polo, J; Grain, J
2011-12-16
This Letter aims at showing that the observation of evaporating black holes should allow the usual Hawking behavior to be distinguished from loop quantum gravity (LQG) expectations. We present a full Monte Carlo simulation of the evaporation in LQG and statistical tests that discriminate between competing models. We conclude that contrarily to what was commonly thought, the discreteness of the area in LQG leads to characteristic features that qualify evaporating black holes as objects that could reveal quantum gravity footprints. PMID:22243065
Primordial black holes with mass 10{sup 16}−10{sup 17} g and reionization of the Universe
Belotsky, K.M.; Kirillov, A.A. E-mail: kirillov-aa@yandex.ru
2015-01-01
Primordial black holes (PBHs) with mass 10{sup 16}−10{sup 17} g almost escape constraints from observations so could essentially contribute to dark matter density. Hawking evaporation of such PBHs produces with a steady rate γ- and e{sup ±}-radiations in MeV energy range, which can be absorbed by ordinary matter. Simplified estimates show that a small fraction of evaporated energy had to be absorbed by baryonic matter what can turn out to be enough to heat the matter so it is fully ionized at the redshift z∼ 5... 10. The result is found to be close to a borderline case where the effect appears, what makes it sensitive to the approximation used. In our approximation, degree of gas ionization reaches 50-100% by z∼ 5 for PBH mass (3...7)× 10{sup 16} g with their abundance corresponding to the upper limit.
Massive antigravity field and incomplete black hole evaporation
NASA Astrophysics Data System (ADS)
Massa, Corrado
2008-04-01
If gravity is a mixture of the ordinary attractive force carried by the massless graviton, and of a repulsive force carried by a particle with nonzero mass, an evaporating black hole might leave a stable remnant.
Surprises in the evaporation of 2D black holes.
Ashtekar, Abhay; Pretorius, Frans; Ramazanoğlu, Fethi M
2011-04-22
Quantum evaporation of Callan-Giddings-Harvey-Strominger black holes is analyzed in the mean-field approximation, incorporating backreaction. Detailed analytical and numerical calculations show that, while some of the assumptions underlying the standard evaporation paradigm are borne out, several are not. Furthermore, if the black hole is initially macroscopic, the evaporation process exhibits remarkable universal properties (which are distinct from the features observed in the simplified, exactly soluble models). Finally, our results provide support for the full quantum gravity scenario recently developed by Ashtekar, Taveras, and Varadarajan. PMID:21599354
a Self-Consistent Model of the Black Hole Evaporation
NASA Astrophysics Data System (ADS)
Kawai, Hikaru; Matsuo, Yoshinori; Yokokura, Yuki
2013-06-01
We construct a self-consistent model which describes a black hole from formation to evaporation including the backreaction from the Hawking radiation. In the case where a null shell collapses, at the beginning the evaporation occurs, but it stops eventually, and a horizon and singularity appear. On the other hand, in the generic collapse process of a continuously distributed null matter, the black hole evaporates completely without forming a macroscopically large horizon nor singularity. We also find a stationary solution in the heat bath, which can be regarded as a normal thermodynamic object.
Black hole evaporation in a noncommutative charged Vaidya model
NASA Astrophysics Data System (ADS)
Sharif, M.; Javed, W.
2012-06-01
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordström-like solution of this model, which leads to an exact ( t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Black hole evaporation in a noncommutative charged Vaidya model
Sharif, M. Javed, W.
2012-06-15
We study the black hole evaporation and Hawking radiation for a noncommutative charged Vaidya black hole. For this purpose, we determine a spherically symmetric charged Vaidya model and then formulate a noncommutative Reissner-Nordstroem-like solution of this model, which leads to an exact (t - r)-dependent metric. The behavior of the temporal component of this metric and the corresponding Hawking temperature are investigated. The results are shown in the form of graphs. Further, we examine the tunneling process of charged massive particles through the quantum horizon. We find that the tunneling amplitude is modified due to noncommutativity. Also, it turns out that the black hole evaporates completely in the limits of large time and horizon radius. The effect of charge is to reduce the temperature from a maximum value to zero. We note that the final stage of black hole evaporation is a naked singularity.
Paul, B. C.; Ghose, S.; Saha, A.
2008-10-15
We investigate multidimensional universe with nonlinear scalar curvature terms to evaluate the probability of creation of primordial black holes. For this we obtain Euclidean instanton solution in two different topologies: (a) S{sup D-1}--topology which does not accommodate primordial black holes and (b) S{sup 1}xS{sup D-2}--topology which accommodates a pair of black holes. The probability for quantum creation of an inflationary universe with a pair of black holes has been evaluated assuming a gravitational action which is described by a polynomial function of scalar curvature with or without a cosmological constant ({lambda}) using the framework of semiclassical approximation of Hartle-Hawking boundary conditions. We discuss here a class of new gravitational instantons solution in the R{sup 4} theory which are relevant for cosmological model building.
Moduli vacuum bubbles produced by evaporating black holes
Morris, J. R.
2007-10-15
We consider a model with a toroidally compactified extra dimension giving rise to a temperature-dependent 4D effective potential with one-loop contributions due to the Casimir effect, along with a 5D cosmological constant. The forms of the effective potential at low and high temperatures indicate a possibility for the formation of a domain wall bubble, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum bubble arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys. Rev. D 74, 024004 (2006)]. The black hole bubble can be highly opaque to lower-energy particles and photons, and thereby entrap them within. For high-temperature black holes, there may also be a symmetry-breaking black hole bubble of false vacuum of the type previously conjectured by Moss [I. G. Moss, Phys. Rev. D 32, 1333 (1985)], tending to reflect low-energy particles from its wall. A double bubble composed of these two different types of bubble may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum bubbles behind that contribute to the dark matter.
To Collapse or not to Collapse: The Life of a Primordial Black Hole
NASA Astrophysics Data System (ADS)
Craig, Robert; Bloomfield, Jolyon; Face, Stephen
2016-03-01
Primordial black holes offer insights into topics ranging from cosmological questions about inflationary models to astrophysical questions regarding supermassive black holes. Such insights depend on being able to predict the number density of black holes that form from primordial fluctuations. Traditionally this has been done by means of a ``rule-of-thumb'' developed by Carr in the 1980s, but recent numerical studies have shown that this predictor is a coarse tool at best. We present a two-parameter predictor with much more discrimination power that can be straightforwardly used to compute number densities. We also discuss challenges that face this type of prediction strategy, both analytically and numerically, and possible ways to circumvent them.
Search for gravitational waves from primordial black hole binary coalescences in the galactic halo
NASA Astrophysics Data System (ADS)
Abbott, B.; Abbott, R.; Adhikari, R.; Ageev, A.; Allen, B.; Amin, R.; Anderson, S. B.; Anderson, W. G.; Araya, M.; Armandula, H.; Ashley, M.; Asiri, F.; Aufmuth, P.; Aulbert, C.; Babak, S.; Balasubramanian, R.; Ballmer, S.; Barish, B. C.; Barker, C.; Barker, D.; Barnes, M.; Barr, B.; Barton, M. A.; Bayer, K.; Beausoleil, R.; Belczynski, K.; Bennett, R.; Berukoff, S. J.; Betzwieser, J.; Bhawal, B.; Bilenko, I. A.; Billingsley, G.; Black, E.; Blackburn, K.; Blackburn, L.; Bland, B.; Bochner, B.; Bogue, L.; Bork, R.; Bose, S.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Brown, D. A.; Bullington, A.; Bunkowski, A.; Buonanno, A.; Burgess, R.; Busby, D.; Butler, W. E.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Camp, J. B.; Cantley, C. A.; Cardenas, L.; Carter, K.; Casey, M. M.; Castiglione, J.; Chandler, A.; Chapsky, J.; Charlton, P.; Chatterji, S.; Chelkowski, S.; Chen, Y.; Chickarmane, V.; Chin, D.; Christensen, N.; Churches, D.; Cokelaer, T.; Colacino, C.; Coldwell, R.; Coles, M.; Cook, D.; Corbitt, T.; Coyne, D.; Creighton, J. D. E.; Creighton, T. D.; Crooks, D. R. M.; Csatorday, P.; Cusack, B. J.; Cutler, C.; D'Ambrosio, E.; Danzmann, K.; Daw, E.; Debra, D.; Delker, T.; Dergachev, V.; Desalvo, R.; Dhurandhar, S.; Credico, A. Di; Díaz, M.; Ding, H.; Drever, R. W. P.; Dupuis, R. J.; Edlund, J. A.; Ehrens, P.; Elliffe, E. J.; Etzel, T.; Evans, M.; Evans, T.; Fairhurst, S.; Fallnich, C.; Farnham, D.; Fejer, M. M.; Findley, T.; Fine, M.; Finn, L. S.; Franzen, K. Y.; Freise, A.; Frey, R.; Fritschel, P.; Frolov, V. V.; Fyffe, M.; Ganezer, K. S.; Garofoli, J.; Giaime, J. A.; Gillespie, A.; Goda, K.; González, G.; Goßler, S.; Grandclément, P.; Grant, A.; Gray, C.; Gretarsson, A. M.; Grimmett, D.; Grote, H.; Grunewald, S.; Guenther, M.; Gustafson, E.; Gustafson, R.; Hamilton, W. O.; Hammond, M.; Hanson, J.; Hardham, C.; Harms, J.; Harry, G.; Hartunian, A.; Heefner, J.; Hefetz, Y.; Heinzel, G.; Heng, I. S.; Hennessy, M.; Hepler, N.; Heptonstall, A.; Heurs, M.; Hewitson, M.; Hild, S.; Hindman, N.; Hoang, P.; Hough, J.; Hrynevych, M.; Hua, W.; Ito, M.; Itoh, Y.; Ivanov, A.; Jennrich, O.; Johnson, B.; Johnson, W. W.; Johnston, W. R.; Jones, D. I.; Jones, L.; Jungwirth, D.; Kalogera, V.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kells, W.; Kern, J.; Khan, A.; Killbourn, S.; Killow, C. J.; Kim, C.; King, C.; King, P.; Klimenko, S.; Koranda, S.; Kötter, K.; Kovalik, J.; Kozak, D.; Krishnan, B.; Landry, M.; Langdale, J.; Lantz, B.; Lawrence, R.; Lazzarini, A.; Lei, M.; Leonor, I.; Libbrecht, K.; Libson, A.; Lindquist, P.; Liu, S.; Logan, J.; Lormand, M.; Lubiński, M.; Lück, H.; Lyons, T. T.; Machenschalk, B.; Macinnis, M.; Mageswaran, M.; Mailand, K.; Majid, W.; Malec, M.; Mann, F.; Marin, A.; Márka, S.; Maros, E.; Mason, J.; Mason, K.; Matherny, O.; Matone, L.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McHugh, M.; McNabb, J. W. C.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messaritaki, E.; Messenger, C.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Miyoki, S.; Mohanty, S.; Moreno, G.; Mossavi, K.; Mueller, G.; Mukherjee, S.; Murray, P.; Myers, J.; Nagano, S.; Nash, T.; Nayak, R.; Newton, G.; Nocera, F.; Noel, J. S.; Nutzman, P.; Olson, T.; O'Reilly, B.; Ottaway, D. J.; Ottewill, A.; Ouimette, D.; Overmier, H.; Owen, B. J.; Pan, Y.; Papa, M. A.; Parameshwaraiah, V.; Parameswaran, A.; Parameswariah, C.; Pedraza, M.; Penn, S.; Pitkin, M.; Plissi, M.; Prix, R.; Quetschke, V.; Raab, F.; Radkins, H.; Rahkola, R.; Rakhmanov, M.; Rao, S. R.; Rawlins, K.; Ray-Majumder, S.; Re, V.; Redding, D.; Regehr, M. W.; Regimbau, T.; Reid, S.; Reilly, K. T.; Reithmaier, K.; Reitze, D. H.; Richman, S.; Riesen, R.; Riles, K.; Rivera, B.; Rizzi, A.; Robertson, D. I.; Robertson, N. A.; Robison, L.; Roddy, S.; Rollins, J.; Romano, J. D.; Romie, J.; Rong, H.; Rose, D.; Rotthoff, E.; Rowan, S.; Rüdiger, A.; Russell, P.; Ryan, K.; Salzman, I.; Sandberg, V.; Sanders, G. H.; Sannibale, V.; Sathyaprakash, B.; Saulson, P. R.; Savage, R.; Sazonov, A.; Schilling, R.; Schlaufman, K.; Schmidt, V.; Schnabel, R.; Schofield, R.; Schutz, B. F.; Schwinberg, P.; Scott, S. M.; Seader, S. E.; Searle, A. C.; Sears, B.; Seel, S.; Seifert, F.; Sengupta, A. S.; Shapiro, C. A.; Shawhan, P.; Shoemaker, D. H.; Shu, Q. Z.; Sibley, A.; Siemens, X.; Sievers, L.; Sigg, D.; Sintes, A. M.; Smith, J. R.; Smith, M.; Smith, M. R.; Sneddon, P. H.; Spero, R.; Stapfer, G.; Steussy, D.; Strain, K. A.; Strom, D.; Stuver, A.; Summerscales, T.; Sumner, M. C.; Sutton, P. J.; Sylvestre, J.; Takamori, A.; Tanner, D. B.; Tariq, H.; Taylor, I.; Taylor, R.; Taylor, R.; Thorne, K. A.; Thorne, K. S.; Tibbits, M.; Tilav, S.; Tinto, M.; Tokmakov, K. V.; Torres, C.; Torrie, C.; Traylor, G.; Tyler, W.; Ugolini, D.; Ungarelli, C.; Vallisneri, M.; van Putten, M.; Vass, S.; Vecchio, A.
2005-10-01
We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole binary coalescence with component masses in the range 0.2-1.0M⊙. The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing nonspinning black holes with masses in the range 0.2-1.0M⊙, we place an observational upper limit on the rate of primordial black hole coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence.
Black-hole evaporation and ultrashort distances
Jacobson, T. )
1991-09-15
The role played by ultrahigh frequencies of ultrashort distances in the usual derivations of the Hawking effect is discussed and criticized. The question would a blackhole radiate if there were a Planck scale cutoff in the rest frame of the hole '' is posed. Guidance is sought from Unruh's fluid-flow analogue of black-hole radiation, by taking into account the atomic nature of the fluid. Two arguments for black-hole radiation are given which assume a Planck length cutoff. One involves the response of static accelerated detectors outside the horizon, and the other involves conservation of the expectation value of the stress tensor. Neither argument is conclusive, but they do strongly suggest that, in spite of reasonable doubt about the usual derivations of black-hole radiation, a safe'' derivation which avoids our ignorance of ultrashort-distance physics can likely be formulated. Remaining open questions are discussed.
Constraints on primordial black holes from the Galactic gamma-ray background
NASA Astrophysics Data System (ADS)
Carr, B. J.; Kohri, Kazunori; Sendouda, Yuuiti; Yokoyama, Jun'ichi
2016-08-01
The fraction of the Universe going into primordial black holes (PBHs) with initial mass M*≈5 ×1 014 g , such that they are evaporating at the present epoch, is strongly constrained by observations of both the extragalactic and Galactic γ -ray backgrounds. However, while the dominant contribution to the extragalactic background comes from the time-integrated emission of PBHs with initial mass M* , the Galactic background is dominated by the instantaneous emission of those with initial mass slightly larger than M* and current mass below M* . Also, the instantaneous emission of PBHs smaller than 0.4 M* mostly comprises secondary particles produced by the decay of directly emitted quark and gluon jets. These points were missed in the earlier analysis by Lehoucq et al. using EGRET data. For a monochromatic PBH mass function, with initial mass (1 +μ )M* and μ ≪1 , the current mass is (3 μ )1 /3M* , and the Galactic background constrains the fraction of the Universe going into PBHs as a function of μ . However, the initial mass function cannot be precisely monochromatic, and even a tiny spread of mass around M* would generate a current low-mass tail of PBHs below M* . This tail would be the main contributor to the Galactic background, so we consider its form and the associated constraints for a variety of scenarios with both extended and nearly monochromatic initial mass functions. In particular, we consider a scenario in which the PBHs form from critical collapse and have a mass function which peaks well above M* . In this case, the largest PBHs could provide the dark matter without the M* ones exceeding the γ -ray background limits.
Particles Generation and Bose Instability in Primordial Rotating Black Holes
NASA Astrophysics Data System (ADS)
Gaina, Alex
The author makes a connection between the Kepler's laws of motion for planets in the gravitational field of the Sun with the motion of test particles in classical mechanics. Subsequently He discusses the quantum problem, or the motion of scalar particles described by Klein-Gordon equation in the gravitational field of a black hole, when the Particle's Energy is less than the Rest Energy of the Particle: E< mc^2. It is mentioned that the spectrum of energies will be discrete one as in the case of the Hydrogen atom. But, due to very fast decreasing of the Potential energy of the particle near the horizon of the Black Hole, or the Black Hole itself, the spectrum will be a quasidiscrete one. The imaginary part of the Energy describes the fall of the particle into Black Hole. There are two features, which could complicate the problem: 1) The rotation of the Black Hole 2) The spin of the Particles. The first circumstance will lead, as is shown by author, to superradiation (the Imaginary part of the Energy will change the sign) as in the case of Particles scattering (E>mc^2). As in that case detailed calculations show that the black Hole will drop the angular momentum very fast if the black Hole is highly rotating. Electrically charged particles cannot develop such a process due to very fast ionization of bosonic levels by electromagnetic radiation. Meanwhile, neutral particles produces Gamma-bursts of energies 67.5, 274.5, 932 Mev correspondingly. The duration of bursts is 1.26* 10^-17 s (for neutral pion), 2.99*10^-18 s (for Eta meson), 8.55*10^-19 s (for D^0 meson). The radiated energies are 1.2 * 10^35 erg, 8.67*10^34 erg, 8.55*10^33 erg, corresponding to very great powers of the order of magnitude 10^52 erg/s. The second circumstance does stops the superradiative decay due to Pauli exclussion principle. The imaginary part of the Energy will not change the sign, and the particles levels are decaying only. For this reason the superradiative bound levels decay of the
Primordial black holes: tunnelling vs. no boundary proposal.
NASA Astrophysics Data System (ADS)
Bousso, R.; Hawking, S. W.
In the inflationary era black holes came into existence together with the universe through the quantum process of pair creation. The authors calculate the pair creation rate from the no boundary proposal for the wave function of the universe. The results are physically sensible and fit in with other descriptions of pair creation. The tunnelling proposal, on the other hand, predicts a catastrophic instability of de Sitter space to the nucleation of large black holes, and cannot be maintained.
A New Method of Detecting Primordial Black Hole Dark Matter using Microlensing
NASA Astrophysics Data System (ADS)
Cieplak, Agnieszka; Griest, K.; Lehner, M. J.
2012-01-01
Primordial Black Holes (PBHs) are the only remaining Dark Matter (DM) candidate of the Standard Model of Particle Physics. We present a new method of constraining up to 40% of the remaining mass range of the PBH DM using microlensing of stars targeted by NASA's Kepler mission. Kepler's exceptional photometric precision and finite-source effects allow for a higher microlensing rate than previously thought. We introduce a new formalism with these effects for the optical depth and microlensing rate.
Nakama, Tomohiro; Harada, Tomohiro; Polnarev, A.G.; Yokoyama, Jun'ichi E-mail: harada@rikkyo.ac.jp E-mail: yokoyama@resceu.s.u-tokyo.ac.jp
2014-01-01
Primordial black holes (PBHs) are an important tool in cosmology to probe the primordial spectrum of small-scale curvature perturbations that reenter the cosmological horizon during radiation domination epoch. We numerically solve the evolution of spherically symmetric highly perturbed configurations to clarify the criteria of PBHs formation using an extremely wide class of curvature profiles characterized by five parameters, (in contrast to only two parameters used in all previous papers) which specify the curvature profiles not only at the central region but also at the outer boundary of configurations. It is shown that formation or non-formation of PBHs is determined essentialy by only two master parameters one of which can be presented as an integral of curvature over initial configurations and the other is presented in terms of the position of the boundary and the edge of the core.
Long time black hole evaporation with bounded Hawking flux
NASA Astrophysics Data System (ADS)
Grumiller, D.
2004-05-01
The long time behaviour of an evaporating black hole presents a challenge to theoretical physics and touches relevant conceptual issues of quantum gravity, such as the information paradox. There are basically two strategies: top-down, i.e., constructing first a full quantum theory of gravity and discussing black hole evaporation as a particular application thereof, and bottom-up, i.e., sidestepping the difficulties inherent to the former approach by invoking `reasonable' ad hoc assumptions. Exploiting the fact that the Schwarzschild black hole can be described by means of an effective theory in 2D, a particular dilaton gravity model, the latter route is pursued. A crucial technical ingredient is Izawa's result on consistent deformations of 2D BF theory, while the most relevant physical assumption is boundedness of the asymptotic matter flux during the whole evaporation process. Together with making technical assumptions which can be relaxed, the dynamics of the evaporating black hole is described by means of consistent deformations of the underlying gauge symmetries with only one important deformation parameter. An attractor solution, the end-point of the evaporation process, is found. Its metric is flat. However, the behaviour of the dilaton field (which corresponds to the surface area) is non-trivial: it is argued that during the final flicker a first-order phase transition occurs from a linear to a constant dilaton vacuum. Consequently, a shock wave is emitted as a final `thunderbolt' with a total energy of a fraction of the Planck mass. Relations to ultrarelativistic boosts are pointed out. Another fraction of the Planck mass may reside in a cold remnant. The physical discussion addresses the lifetime, the specific heat, the Carter Penrose diagram, the information paradox and cosmological implications. The phenomenon of `dilaton evaporation' to a constant dilaton vacuum might be of relevance also for higher dimensional scalar tensor theories. Based on an
The lifetime problem of evaporating black holes: mutiny or resignation
NASA Astrophysics Data System (ADS)
Barceló, Carlos; Carballo-Rubio, Raúl; Garay, Luis J.; Jannes, Gil
2015-02-01
It is logically possible that regularly evaporating black holes (REBHs) exist in nature. In fact, the prevalent theoretical view is that these are indeed the real objects behind the curtain in astrophysical scenarios. There are several proposals for regularizing the classical singularity of black holes so that their formation and evaporation do not lead to information-loss problems. One characteristic is shared by most of these proposals: these REBHs present long-lived trapping horizons, with absolutely enormous evaporation lifetimes in whatever measure. Guided by the discomfort with these enormous and thus inaccessible lifetimes, we elaborate here on an alternative regularization of the classical singularity, previously proposed by the authors in an emergent gravity framework, which leads to a completely different scenario. In our scheme the collapse of a stellar object would result in a genuine time-symmetric bounce, which in geometrical terms amounts to the connection of a black-hole geometry with a white-hole geometry in a regular manner. The two most differential characteristics of this proposal are: (i) the complete bouncing geometry is a solution of standard classical general relativity everywhere except in a transient region that necessarily extends beyond the gravitational radius associated with the total mass of the collapsing object; and (ii) the duration of the bounce as seen by external observers is very brief (fractions of milliseconds for neutron-star-like collapses). This scenario motivates the search for new forms of stellar equilibrium different from black holes. In a brief epilogue we compare our proposal with a similar geometrical setting recently proposed by Haggard and Rovelli.
Low-mass black holes as the remnants of primordial black hole formation
NASA Astrophysics Data System (ADS)
Greene, Jenny E.
2012-12-01
Bridging the gap between the approximately ten solar mass `stellar mass' black holes and the `supermassive' black holes of millions to billions of solar masses are the elusive `intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ~104-105Msolar black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.
New constraints on the primordial black hole number density from Galactic γ-ray astronomy
NASA Astrophysics Data System (ADS)
Lehoucq, R.; Cassé, M.; Casandjian, J.-M.; Grenier, I.
2009-07-01
Context: Primordial black holes are unique probes of cosmology, general relativity, quantum gravity and non standard particle physics. They open a new window on the very small scales in the early Universe and also can be considered as the ultimate particle accelerator in their last (explosive) moments since they are supposed to reach, very briefly, the Planck temperature. Aims: Upper limits on the primordial black hole number density of mass Mstar = 5×1014 g, the Hawking mass (born in the big-bang terminating their life presently), is determined comparing their predicted cumulative γ-ray emission, galaxy-wise, to the one observed by the EGRET satellite, once corrected for non thermal γ-ray background emission induced by cosmic ray protons and electrons interacting with light and matter in the Milky Way. Methods: A model with free gas emissivities is used to map the Galaxy in the 100 MeV photon range, where the peak of the primordial black hole emission is expected. The best gas emissivities and additional model parameters are obtained by fitting the EGRET data and are used to derive the maximum emission of the primordial black hole of the Hawking mass, assuming that they are distributed like the dark matter in the Galactic halo. Results: The bounds we obtain, depending on the dark matter distribution, extrapolated to the whole Universe (Ω_PBH(Mstar) = 2.4×10-10 to 2.6×10-9) are more stringent than the previous ones derived from extragalactic γ-ray background and antiprotons fluxes, though less model dependent and based on more robust data. Conclusions: These new limits have interesting consequences on the theory of the formation of small structures in the Universe, since they are the only constraint on very small scale density fluctuations left by inflation. Significant improvements by data gathered by the FERMI γ-ray satellite are expected in the near future. The interest of a generalisation of this work beyond the standard particle model and in
Gravitational-wave background as a probe of the primordial black-hole abundance.
Saito, Ryo; Yokoyama, Jun'ichi
2009-04-24
The formation of a significant number of black holes (PBHs) is realized if and only if primordial density fluctuations have a large amplitude, which means that tensor perturbations generated from these scalar perturbations as a second-order effect are also large and comparable to the observational data. We show that pulsar timing data essentially rule out PBHs with 10;{2}-10;{4}M_{middle dot in circle}, which were previously considered as a candidate of intermediate-mass black holes, and that PBHs with a mass range of 10;{20} to 10;{26} g, which serves as a candidate of dark matter, may be probed by future space-based laser interferometers and atomic interferometers. PMID:19518692
Rapid merger of binary primordial black holes: An implication for GW150914
NASA Astrophysics Data System (ADS)
Hayasaki, Kimitake; Takahashi, Keitaro; Sendouda, Yuuiti; Nagataki, Shigehiro
2016-07-01
We propose a new scenario for the evolution of the binaries of primordial black holes (PBH). We consider dynamical friction by ambient dark matter, scattering of dark matter particles with a highly eccentric orbit besides the standard two-body relaxation process to refill the loss cone, and interaction between the binary and a circumbinary disk, assuming that PBHs do not constitute the bulk of dark matter. Binary PBHs lose the energy and angular momentum by these processes, which could be sufficiently efficient for a typical configuration. Such a binary coalesces due to the gravitational wave emission on a time scale much shorter than the age of the universe. We estimate the density parameter of the resultant gravitational wave background. Astrophysical implications concerning the formation of intermediate-mass to supermassive black holes is also discussed.
Can massive primordial black holes be produced in mild waterfall hybrid inflation?
NASA Astrophysics Data System (ADS)
Kawasaki, Masahiro; Tada, Yuichiro
2016-08-01
We studied the possibility whether the massive primordial black holes (PBHs) surviving today can be produced in hybrid inflation. Though it is of great interest since such PBHs can be the candidate for dark matter or seeds of the supermassive black holes in galaxies, there have not been quantitatively complete works yet because of the non-perturbative behavior around the critical point of hybrid inflation. Therefore, combining the stochastic and δN formalism, we numerically calculated the curvature perturbations in a non-perturbative way and found, without any specific assumption of the types of hybrid inflation, PBHs are rather overproduced when the waterfall phase of hybrid inflation continues so long that the PBH scale is well enlarged and the corresponding PBH mass becomes sizable enough.
Rapid merger of binary primordial black holes: An implication for GW150914
NASA Astrophysics Data System (ADS)
Hayasaki, Kimitake; Takahashi, Keitaro; Sendouda, Yuuiti; Nagataki, Shigehiro
2016-08-01
We propose a new scenario for the evolution of the binaries of primordial black holes (PBH). We consider dynamical friction by ambient dark matter, scattering of dark matter particles with a highly eccentric orbit besides the standard two-body relaxation process to refill the loss cone, and interaction between the binary and a circumbinary disk, assuming that PBHs do not constitute the bulk of dark matter. Binary PBHs lose the energy and angular momentum by these processes, which could be sufficiently efficient for a typical configuration. Such a binary coalesces due to the gravitational wave emission on a time scale much shorter than the age of the universe. We estimate the density parameter of the resultant gravitational wave background. Astrophysical implications concerning the formation of intermediate-mass to supermassive black holes is also discussed.
Low-mass black holes as the remnants of primordial black hole formation.
Greene, Jenny E
2012-01-01
Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism. PMID:23250434
Black hole evaporation: information loss but no paradox
NASA Astrophysics Data System (ADS)
Modak, Sujoy K.; Ortíz, Leonardo; Peña, Igor; Sudarsky, Daniel
2015-10-01
The process of black hole evaporation resulting from the Hawking effect has generated an intense controversy regarding its potential conflict with quantum mechanics' unitary evolution. A recent set of works by a collaboration involving one of us, have revised the controversy with the aims of, on one hand, clarifying some conceptual issues surrounding it, and, at the same time, arguing that collapse theories have the potential to offer a satisfactory resolution of the so-called paradox. Here we show an explicit calculation supporting this claim using a simplified model of black hole creation and evaporation, known as the CGHS model, together with a dynamical reduction theory, known as CSL, and some speculative, but seemingly natural ideas about the role of quantum gravity in connection with the would-be singularity. This work represents a specific realization of general ideas first discussed in Okon and Sudarsky (Found Phys 44:114-143, 2014 and a complete and detailed analysis of a model first considered in Modak et al. (Phys Rev D 91(12):124009, 2015.
Running spectral index and formation of primordial black hole in single field inflation models
Drees, Manuel; Erfani, Encieh E-mail: erfani@th.physik.uni-bonn.de
2012-01-01
A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of long-lived Primordial Black Holes (PBHs). To that end we calculate the spectral index of the power spectrum of primordial perturbations as well as its first and second derivatives. PBH formation is possible only if the spectral index increases significantly at small scales, i.e. large wave number k. Since current data indicate that the first derivative α{sub S} of the spectral index n{sub S}(k{sub 0}) is negative at the pivot scale k{sub 0}, PBH formation is only possible in the presence of a sizable and positive second derivative (''running of the running'') β{sub S}. Among the three small-field and five large-field models we analyze, only one small-field model, the ''running mass'' model, allows PBH formation, for a narrow range of parameters. We also note that none of the models we analyze can accord for a large and negative value of α{sub S}, which is weakly preferred by current data.
Black Hole Evaporation and the Role of Ultrashort Distances
NASA Astrophysics Data System (ADS)
Hambli, Noureddine
The role played by ultrahigh frequencies or ultrashort distances in the usual derivation of the Hawking effect is discussed. We demonstrate the robustness of Hawking's prediction of black-hole evaporation, by carrying out an explicit calculation, in which short-distance physics is explicitly regularized using the Pauli-Villars regularization scheme. We find that short-distance effects due to physics at small distance scales, 1/Lambda gg 1/TH, where 1/Lambda is a covariantly chosen short-distance cutoff, can only contribute to the Hawking flux an amount that is exponentially suppressed by the large ratio Lambda/TH. We argue further that this behavior is not specific to our choice of regularization, but is a generic feature of any covariant short-distance regularization. We do so by showing that no possible covariant and local counterterm exists which can contribute to the Hawking flux at late times far from the hole.
Microlensing of Kepler stars as a method of detecting primordial black hole dark matter.
Griest, Kim; Lehner, Matthew J; Cieplak, Agnieszka M; Jain, Bhuvnesh
2011-12-01
If the dark matter consists of primordial black holes (PBHs), we show that gravitational lensing of stars being monitored by NASA's Kepler search for extrasolar planets can cause significant numbers of detectable microlensing events. A search through the roughly 150,000 light curves would result in large numbers of detectable events for PBHs in the mass range 5×10(-10) M(⊙) to 10(-4) M(⊙). Nondetection of these events would close almost 2 orders of magnitude of the mass window for PBH dark matter. The microlensing rate is higher than previously noticed due to a combination of the exceptional photometric precision of the Kepler mission and the increase in cross section due to the large angular sizes of the relatively nearby Kepler field stars. We also present a new formalism for calculating optical depth and microlensing rates in the presence of large finite-source effects. PMID:22182077
Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914
NASA Astrophysics Data System (ADS)
Sasaki, Misao; Suyama, Teruaki; Tanaka, Takahiro; Yokoyama, Shuichiro
2016-08-01
We point out that the gravitational-wave event GW150914 observed by the LIGO detectors can be explained by the coalescence of primordial black holes (PBHs). It is found that the expected PBH merger rate would exceed the rate estimated by the LIGO Scientific Collaboration and the Virgo Collaboration if PBHs were the dominant component of dark matter, while it can be made compatible if PBHs constitute a fraction of dark matter. Intriguingly, the abundance of PBHs required to explain the suggested lower bound on the event rate, >2 events Gpc-3 yr-1 , roughly coincides with the existing upper limit set by the nondetection of the cosmic microwave background spectral distortion. This implies that the proposed PBH scenario may be tested in the not-too-distant future.
New thresholds for Primordial Black Hole formation during the QCD phase transition
NASA Astrophysics Data System (ADS)
Sobrinho, J. L. G.; Augusto, P.; Gonçalves, A. L.
2016-08-01
Primordial Black Holes (PBHs) might have formed in the early Universe as a consequence of the collapse of density fluctuations with an amplitude above a critical value δc: the formation threshold. Although for a radiation-dominated Universe δc remains constant, if the Universe experiences some dust-like phases (e.g. phase transitions) δc might decrease, improving the chances of PBH formation. We studied the evolution of δc during the QCD phase transition epoch within three different models: Bag Model (BM), Lattice Fit Model (LFM), and Crossover Model (CM). We found that the reduction on the background value of δc can be as high as 77% (BM), which might imply a ˜10-10 probability of PBHs forming at the QCD epoch.
Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914.
Sasaki, Misao; Suyama, Teruaki; Tanaka, Takahiro; Yokoyama, Shuichiro
2016-08-01
We point out that the gravitational-wave event GW150914 observed by the LIGO detectors can be explained by the coalescence of primordial black holes (PBHs). It is found that the expected PBH merger rate would exceed the rate estimated by the LIGO Scientific Collaboration and the Virgo Collaboration if PBHs were the dominant component of dark matter, while it can be made compatible if PBHs constitute a fraction of dark matter. Intriguingly, the abundance of PBHs required to explain the suggested lower bound on the event rate, >2 events Gpc^{-3} yr^{-1}, roughly coincides with the existing upper limit set by the nondetection of the cosmic microwave background spectral distortion. This implies that the proposed PBH scenario may be tested in the not-too-distant future. PMID:27541453
New limits on primordial black hole dark matter from an analysis of Kepler source microlensing data.
Griest, Kim; Cieplak, Agnieszka M; Lehner, Matthew J
2013-11-01
We present new limits on the allowed masses of a dark matter (DM) halo consisting of primordial black holes (PBH) (or any other massive compact halo object). We analyze two years of data from the Kepler satellite, searching for short-duration bumps caused by gravitational microlensing. After removing background events consisting of variable stars, flare events, and comets or asteroids moving through the Kepler field, we find no microlensing candidates. We measure the efficiency of our selection criteria by adding millions of simulated microlensing lensing events into the Kepler light curves. We find that PBH DM with masses in the range 2 × 10(-9) M[Symbol: see text] to 10(-7)M[Symbol: see text] cannot make up the entirety of the DM in the Milky Way. At the low-mass end, this decreases the allowed mass range by more than an order of magnititude. PMID:24237504
Improved Predictions of Kepler Microlensing Rates for Primordial Black Hole Dark Matter
NASA Astrophysics Data System (ADS)
Cieplak, Agnieszka; Griest, K.
2013-01-01
Primordial Black Holes (PBHs) remain a viable Dark Matter (DM) candidate of the Standard Model of Particle Physics. Previously, we have proposed a new method to constrain the remaining PBH DM mass range using microlensing of Kepler source stars, with the possibility of closing up to 40% of the remaining mass window. Here we re-address this analysis using a more accurate treatment of the distribution of the source stars, including limb-darkening as well as reflecting a more accurate number of variable stars. Including the extended Kepler mission the theoretically detectable PBH DM mass range could be extended down to 2*10^-10 solar masses. We address the possible PBH parameters that could be detected if such an event would be observed as well as possible improvements for future survey satellite missions.
New Limits on Primordial Black Hole Dark Matter from an Analysis of Kepler Source Microlensing Data
NASA Astrophysics Data System (ADS)
Griest, Kim; Cieplak, Agnieszka M.; Lehner, Matthew J.
2013-11-01
We present new limits on the allowed masses of a dark matter (DM) halo consisting of primordial black holes (PBH) (or any other massive compact halo object). We analyze two years of data from the Kepler satellite, searching for short-duration bumps caused by gravitational microlensing. After removing background events consisting of variable stars, flare events, and comets or asteroids moving through the Kepler field, we find no microlensing candidates. We measure the efficiency of our selection criteria by adding millions of simulated microlensing lensing events into the Kepler light curves. We find that PBH DM with masses in the range 2×10-9M⊙ to 10-7M⊙ cannot make up the entirety of the DM in the Milky Way. At the low-mass end, this decreases the allowed mass range by more than an order of magnititude.
Microlensing of Kepler Stars as a Method of Detecting Primordial Black Hole Dark Matter
NASA Astrophysics Data System (ADS)
Griest, Kim; Lehner, Matthew J.; Cieplak, Agnieszka M.; Jain, Bhuvnesh
2011-12-01
If the dark matter consists of primordial black holes (PBHs), we show that gravitational lensing of stars being monitored by NASA’s Kepler search for extrasolar planets can cause significant numbers of detectable microlensing events. A search through the roughly 150 000 light curves would result in large numbers of detectable events for PBHs in the mass range 5×10-10M⊙ to 10-4M⊙. Nondetection of these events would close almost 2 orders of magnitude of the mass window for PBH dark matter. The microlensing rate is higher than previously noticed due to a combination of the exceptional photometric precision of the Kepler mission and the increase in cross section due to the large angular sizes of the relatively nearby Kepler field stars. We also present a new formalism for calculating optical depth and microlensing rates in the presence of large finite-source effects.
NASA Astrophysics Data System (ADS)
Pani, Paolo; Loeb, Abraham
2013-08-01
We consider the imprint of super-radiant instabilities of nonevaporating primordial black holes (PBHs) on the spectrum of the cosmic microwave background (CMB). In the radiation-dominated era, PBHs are surrounded by a roughly homogeneous cosmic plasma which endows photons with an effective mass through the plasma frequency. In this setting, spinning PBHs are unstable to a spontaneous spindown through the well-known “black hole bomb” mechanism. At the linear level, the photon density is trapped by the effective photon mass and grows exponentially in time due to super-radiance. As the plasma density declines due to cosmic expansion, the associated energy around PBHs is released and dissipated in the CMB. We evaluate the resulting spectral distortions of the CMB in the redshift range 103≲z≲2×106. Using the existing COBE/FIRAS bounds on CMB spectral distortions, we derive upper limits on the fraction of dark matter that can be associated with spinning PBHs in the mass range 10-8M⊙≲M≲0.2M⊙. For maximally spinning PBHs, our limits are much tighter than those derived from microlensing or other methods. Future data from the proposed PIXIE mission could improve our limits by several orders of magnitude.
Massive primordial black holes from hybrid inflation as dark matter and the seeds of galaxies
NASA Astrophysics Data System (ADS)
Clesse, Sébastien; García-Bellido, Juan
2015-07-01
In this paper we present a new scenario where massive primordial black holes (PBHs) are produced from the collapse of large curvature perturbations generated during a mild-waterfall phase of hybrid inflation. We determine the values of the inflaton potential parameters leading to a PBH mass spectrum peaking on planetarylike masses at matter-radiation equality and producing abundances comparable to those of dark matter today, while the matter power spectrum on scales probed by cosmic microwave background (CMB) anisotropies agrees with Planck data. These PBHs could have acquired large stellar masses today, via merging, and the model passes both the constraints from CMB distortions and microlensing. This scenario is supported by Chandra observations of numerous BH candidates in the central region of Andromeda. Moreover, the tail of the PBH mass distribution could be responsible for the seeds of supermassive black holes at the center of galaxies, as well as for ultraluminous x-ray sources. We find that our effective hybrid potential can originate e.g. from D-term inflation with a Fayet-Iliopoulos term of the order of the Planck scale but sub-Planckian values of the inflaton field. Finally, we discuss the implications of quantum diffusion at the instability point of the potential, able to generate a Swiss-cheese-like structure of the Universe, eventually leading to apparent accelerated cosmic expansion.
Pani, Paolo; Loeb, Abraham E-mail: aloeb@cfa.harvard.edu
2014-06-01
In a close encounter with a neutron star, a primordial black hole can get gravitationally captured by depositing a considerable amount of energy into nonradial stellar modes of very high angular number l. If the neutron-star equation of state is sufficiently stiff, we show that the total energy loss in the point-particle approximation is formally divergent. Various mechanisms — including viscosity, finite-size effects and the elasticity of the crust — can damp high-l modes and regularize the total energy loss. Within a short time, the black hole is trapped inside the star and disrupts it by rapid accretion. Estimating these effects, we predict that the existence of old neutron stars in regions where the dark-matter density ρ{sub DM}∼>10{sup 2}(σ/km s{sup −1}) GeV cm{sup −3} (where σ is the dark-matter velocity dispersion) limits the abundance of primordial black holes in the mass range 10{sup 17} g∼
Experimental limits on primordial black hole dark matter from the first 2 yr of Kepler data
Griest, Kim; Cieplak, Agnieszka M.; Lehner, Matthew J.
2014-05-10
We present our analysis on new limits of the dark matter (DM) halo consisting of primordial black holes (PBHs) or massive compact halo objects. We present a search of the first two yr of publicly available Kepler mission data for potential signatures of gravitational microlensing caused by these objects as well as an extensive analysis of the astrophysical sources of background error. These include variable stars, flare events, and comets or asteroids that are moving through the Kepler field. We discuss the potential of detecting comets using the Kepler light curves, presenting measurements of two known comets and one unidentified object, most likely an asteroid or comet. After removing the background events with statistical cuts, we find no microlensing candidates. We therefore present our Monte Carlo efficiency calculation in order to constrain the PBH DM with masses in the range of 2 × 10{sup –9} M {sub ☉} to 10{sup –7} M {sub ☉}. We find that PBHs in this mass range cannot make up the entirety of the DM, thus closing a full order of magnitude in the allowed mass range for PBH DM.
Experimental Limits on Primordial Black Hole Dark Matter from the First 2 yr of Kepler Data
NASA Astrophysics Data System (ADS)
Griest, Kim; Cieplak, Agnieszka M.; Lehner, Matthew J.
2014-05-01
We present our analysis on new limits of the dark matter (DM) halo consisting of primordial black holes (PBHs) or massive compact halo objects. We present a search of the first two yr of publicly available Kepler mission data for potential signatures of gravitational microlensing caused by these objects as well as an extensive analysis of the astrophysical sources of background error. These include variable stars, flare events, and comets or asteroids that are moving through the Kepler field. We discuss the potential of detecting comets using the Kepler light curves, presenting measurements of two known comets and one unidentified object, most likely an asteroid or comet. After removing the background events with statistical cuts, we find no microlensing candidates. We therefore present our Monte Carlo efficiency calculation in order to constrain the PBH DM with masses in the range of 2 × 10-9 M ⊙ to 10-7 M ⊙. We find that PBHs in this mass range cannot make up the entirety of the DM, thus closing a full order of magnitude in the allowed mass range for PBH DM.
NASA Astrophysics Data System (ADS)
Cieplak, Agnieszka M.; Griest, Kim
2013-04-01
Primordial black holes (PBHs) remain a dark matter (DM) candidate of the Standard Model of Particle Physics. Previously, we proposed a new method of constraining the remaining PBH DM mass range using microlensing of stars monitored by NASA's Kepler mission. We improve this analysis using a more accurate treatment of the population of the Kepler source stars, their variability, and limb darkening. We extend the theoretically detectable PBH DM mass range down to 2 × 10-10 M ⊙, two orders of magnitude below current limits and one-third order of magnitude below our previous estimate. We address how to extract the DM properties, such as mass and spatial distribution, if PBH microlensing events were detected. We correct an error in a well-known finite-source limb-darkening microlensing formula and also examine the effects of varying the light curve cadence on PBH DM detectability. We also introduce an approximation for estimating the predicted rate of detection per star as a function of the star's properties, thus allowing for selection of source stars in future missions, and extend our analysis to planned surveys, such as the Wide-Field Infrared Survey Telescope.
NASA Astrophysics Data System (ADS)
Kashlinsky, A.
2016-06-01
LIGO's discovery of a gravitational wave from two merging black holes (BHs) of similar masses rekindled suggestions that primordial BHs (PBHs) make up the dark matter (DM). If so, PBHs would add a Poissonian isocurvature density fluctuation component to the inflation-produced adiabatic density fluctuations. For LIGO's BH parameters, this extra component would dominate the small-scale power responsible for collapse of early DM halos at z ≳ 10, where first luminous sources formed. We quantify the resultant increase in high-z abundances of collapsed halos that are suitable for producing the first generation of stars and luminous sources. The significantly increased abundance of the early halos would naturally explain the observed source-subtracted near-IR cosmic infrared background (CIB) fluctuations, which cannot be accounted for by known galaxy populations. For LIGO's BH parameters, this increase is such that the observed CIB fluctuation levels at 2–5 μm can be produced if only a tiny fraction of baryons in the collapsed DM halos forms luminous sources. Gas accretion onto these PBHs in collapsed halos, where first stars should also form, would straightforwardly account for the observed high coherence between the CIB and unresolved cosmic X-ray background in soft X-rays. We discuss modifications possibly required in the processes of first star formation if LIGO-type BHs indeed make up the bulk or all of DM. The arguments are valid only if the PBHs make up all, or at least most, of DM, but at the same time the mechanism appears inevitable if DM is made of PBHs.
DETECTABLE SEISMIC CONSEQUENCES OF THE INTERACTION OF A PRIMORDIAL BLACK HOLE WITH EARTH
Luo Yang; Hanasoge, Shravan; Tromp, Jeroen; Pretorius, Frans
2012-05-20
Galaxies observed today are likely to have evolved from density perturbations in the early universe. Perturbations that exceeded some critical threshold are conjectured to have undergone gravitational collapse to form primordial black holes (PBHs) at a range of masses. Such PBHs serve as candidates for cold dark matter, and their detection would shed light on conditions in the early universe. Here, we propose a mechanism to search for transits of PBHs through/nearby Earth by studying the associated seismic waves. Using a spectral-element method, we simulate and visualize this seismic wave field in Earth's interior. We predict the emergence of two unique signatures, namely, a wave that would arrive almost simultaneously everywhere on Earth's free surface and the excitation of unusual spheroidal modes with a characteristic frequency spacing in free oscillation spectra. These qualitative characteristics are unaffected by the speed or proximity of the PBH trajectory. The seismic energy deposited by a proximal M{sup PBH} = 10{sup 15} g PBH is comparable to a magnitude M{sub w} = 4 earthquake. The non-seismic collateral damage due to the actual impact of such small PBHs with Earth would be negligible. Unfortunately, the expected collision rate is very low even if PBHs constituted all of dark matter, at {approx}10{sup -7} yr{sup -1}, and since the rate scales as 1/M{sup PBH}, fortunately encounters with larger, Earth-threatening PBHs are exceedingly unlikely. However, the rate at which non-colliding close encounters of PBHs could be detected by seismic activity alone is roughly two orders of magnitude larger-that is once every hundred thousand years-than the direct collision rate.
Spherically Symmetric Trapping Horizons, the Misner-Sharp Mass and Black Hole Evaporation
NASA Astrophysics Data System (ADS)
Nielsen, Alex B.; Yeom, Dong-Han
We discuss some of the issues relating to information loss and black hole thermodynamics in the light of recent work on local black hole horizons. Understood in terms of pure states evolving into mixed states, the possibility of information loss in black holes is closely related to the global causal structure of space-time, as is the existence of event horizons. However, black holes need not be defined by event horizons, and in fact we argue that in order to have a fully unitary evolution for black holes, they should be defined in terms of something else, such as a trapping horizon. The Misner-Sharp mass in spherical symmetry shows very simply how trapping horizons can give rise to black hole thermodynamics, Hawking radiation and singularities. We show how the Misner-Sharp mass can also be used to give insights into the process of collapse and evaporation of locally defined black holes.
Unitarity of black hole evaporation in final-state projection models
NASA Astrophysics Data System (ADS)
Lloyd, Seth; Preskill, John
2014-08-01
Almheiri et al. have emphasized that otherwise reasonable beliefs about black hole evaporation are incompatible with the monogamy of quantum entanglement, a general property of quantum mechanics. We investigate the final-state projection model of black hole evaporation proposed by Horowitz and Maldacena, pointing out that this model admits cloning of quantum states and polygamous entanglement, allowing unitarity of the evaporation process to be reconciled with smoothness of the black hole event horizon. Though the model seems to require carefully tuned dynamics to ensure exact unitarity of the black hole S-matrix, for a generic final-state boundary condition the deviations from unitarity are exponentially small in the black hole entropy; furthermore observers inside black holes need not detect any deviations from standard quantum mechanics. Though measurements performed inside old black holes could potentially produce causality-violating phenomena, the computational complexity of decoding the Hawking radiation may render the causality violation unobservable. Final-state projection models illustrate how inviolable principles of standard quantum mechanics might be circumvented in a theory of quantum gravity.
Hawking evaporation time scale of topological black holes in anti-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Ong, Yen Chin
2016-02-01
It was recently pointed out that if an absorbing boundary condition is imposed at infinity, an asymptotically anti-de Sitter Schwarzschild black hole with a spherical horizon takes only a finite amount of time to evaporate away even if its initial mass is arbitrarily large. We show that this is a rather generic property in AdS spacetimes: regardless of their horizon topologies, neutral AdS black holes in general relativity take about the same amount of time to evaporate down to the same size of order L, the AdS length scale. Our discussion focuses on the case in which the black hole has toral event horizon. A brief comment is made on the hyperbolic case, i.e. for black holes with negatively curved horizons.
Evaporation of near-extremal Reissner-Nordström black holes.
Fabbri, A; Navarro, D J; Navarro-Salas, J
2000-09-18
The formation of near-extremal Reissner-Nordström black holes in the S-wave approximation can be described, near the event horizon, by an effective solvable model. The corresponding one-loop quantum theory remains solvable and allows one to follow analytically the evaporation process, which is shown to require an infinite amount of time. PMID:10978075
A new method dealing with hawking effects of evaporating black holes
Zhao, Z.; Dai, X. )
1992-06-28
This paper reports that, both the location and the temperature of event horizons of evaporating black holes can be easily given if one proposes the Klein-Gordon equation approaches the standard form of wave equation near event horizons by using tortoise-type coordinates.
NASA Technical Reports Server (NTRS)
Smoot, G. F.
1981-01-01
Large-angular-scale anisotropies in the 3 K primordial black-body radiation were detected and mapped with a sensitivity of 2 x to the minus 4 power K and an angular resolution of about 10 deg. The motion of the Earth with respect to the distant matter of the Universe ("Aether Drift") was measured and the homogeneity and isotropy of the Universe (the "Cosmological Principle") was probed. The experiment uses two Dicke radiometers, one at 33 GHz to detect the cosmic anisotropy, and one at 54 GHz to detect anisotropies in the residual oxygen above the detectors. The system was installed in the NASA-Ames Earth survey aircraft (U-2), and operated successfully in a series of flights in both the Northern and Southern Hemispheres. Data taking and analysis to measure the anisotropy were successful.
NASA Technical Reports Server (NTRS)
Muller, R. A.
1979-01-01
This experiment detected and mapped large-angular-scale anisotropies in the 3 K primordial black-body radiation with a sensitivity of 2x.0001k and an angular resolution of about 10 degs. It measured the motion of the Earth with respect to the distant matter of the Universe (Aether Drift), and probed the homogeneity and isotropy of the Universe (the Cosmological Principle). The experiment used two Dicke radiometers, one at 33 GHz to detect the cosmic anisotropy, and one at 54 GHz to detect anisotropies in the residual oxygen above the detectors. The system was installed in the NASA-Ames Earth Survey Aircraft (U-2), and operated successfully in a series of flights.
Construction of a Penrose Diagram for a Spatially Coherent Evaporating Black Hole
NASA Technical Reports Server (NTRS)
Brown, Beth A.; Lindesay, James
2007-01-01
A Penrose diagram is constructed for an example black hole that evaporates at a steady rate as measured by a distant observer, until the mass vanishes, yielding a final state Minkowski space-time. Coordinate dependencies of significant features, such as the horizon and coordinate anomalies, are clearly demonstrated on the diagram. The large-scale causal structure of the space-time is briefly discussed.
Probability of primordial black hole pair creation in a modified gravitational theory
Paul, B. C.; Paul, Dilip
2006-10-15
We compute the probability for quantum creation of an inflationary universe with and without a pair of black holes in a modified gravity. The action of the modified theory of gravity contains {alpha}R{sup 2} and {delta}R{sup -1} terms in addition to a cosmological constant ({lambda}) in the Einstein-Hilbert action. The probabilities for the creation of universe with a pair of black holes have been evaluated considering two different kinds of spatial sections, one which accommodates a pair of black holes and the other without black hole. We adopt a technique prescribed by Bousso and Hawking to calculate the above creation probability in a semiclassical approximation using the Hartle-Hawking boundary condition. We note a class of new and physically interesting instanton solutions characterized by the parameters in the action. These instantons may play an important role in the creation of the early universe. We also note that the probability of creation of a universe with a pair of black holes is strongly suppressed with a positive cosmological constant when {delta}=(4{lambda}{sup 2}/3) for {alpha}>0 but it is more probable for {alpha}<-(1/6{lambda}). In the modified gravity considered here instanton solutions are permitted even without a cosmological constant when one begins with a negative {delta}.
NASA Astrophysics Data System (ADS)
Yan, Hao-Peng; Liu, Wen-Biao
2016-08-01
Using Parikh-Wilczek tunneling framework, we calculate the tunneling rate from a Schwarzschild black hole under the third order WKB approximation, and then obtain the expressions for emission spectrum and black hole entropy to the third order correction. The entropy contains four terms including the Bekenstein-Hawking entropy, the logarithmic term, the inverse area term, and the square of inverse area term. In addition, we analyse the correlation between sequential emissions under this approximation. It is shown that the entropy is conserved during the process of black hole evaporation, which consists with the request of quantum mechanics and implies the information is conserved during this process. We also compare the above result with that of pure thermal spectrum case, and find that the non-thermal correction played an important role.
Collapse of primordial gas clouds and the formation of quasar black holes
NASA Technical Reports Server (NTRS)
Loeb, Abraham; Rasio, Frederic A.
1994-01-01
The formation of quasar black holes during the hydrodynamic collapse of protogalactic gas clouds is discussed. The dissipational collapse and long-term dynamical evolution of these systems is analyzed using three-dimensional numerical simulations. The calculations focus on the final collapse stages of the inner baryonic component and therefore ignore the presence of dark matter. Two types of initial conditions are considered: uniformly rotating spherical clouds, and iirotational ellipsoidal clouds. In both cases the clouds are initially cold, homogeneous, and not far from rotational support (T/(absolute value of W) approximately equals 0.1). Although the details of the dynamical evolution depend sensitively on the initial conditions, the qualitative features of the final configurations do not. Most of the gas is found to fragment into small dense clumps, that eventually make up a spheroidal component resembling a galactic bulge. About 5% of the initial mass remains in the form of a smooth disk of gas supported by rotation in the gravitational potential potential well of the outer spheroid. If a central seed black hole of mass approximately greater than 10(exp 6) solar mass forms, it can grow by steady accretion from the disk and reach a typical quasar black hole mass approximately 10(exp 8) solar mass in less than 5 x 10(exp 8) yr. In the absence of a sufficiently massive seed, dynamical instabilities in a strongly self-gravitating inner region of the disk will inhibit steady accretion of gas and may prevent the immediate formation of quasar.
Probability for a primordial black hole pair in 1/R gravity
Paul, Dilip; Paul, Bikash Chandra
2005-09-15
The probability for quantum creation of an inflationary universe with a pair of black holes in 1/R-gravitational theory has been studied. Considering a gravitational action which includes a cosmological constant ({lambda}) in addition to {delta}R{sup -1} term, the probability has been evaluated in a semiclassical approximation with Hartle-Hawking boundary condition. We obtain instanton solutions determined by the parameters {delta} and {lambda} satisfying the constraint {delta}{<=}(4{lambda}{sup 2}/3). However, we note that two different classes of instanton solutions exists in the region 0<{delta}<(4{lambda}{sup 2}/3). The probabilities of creation of such configurations are evaluated. It is found that the probability of creation of a universe with a pair of black holes is strongly suppressed with a positive cosmological constant except in one case when 0<{delta}<{lambda}{sup 2}. It is also found that gravitational instanton solution is permitted even with {lambda}=0 but one has to consider {delta}<0. However, in the later case a universe with a pair of black holes is less probable.
Sendouda, Yuuiti; Kohri, Kazunori; Nagataki, Shigehiro; Sato, Katsuhiko
2005-03-15
We investigate cosmic-ray antiprotons emitted from the galactic primordial black holes (PBHs) in the Randall-Sundrum type-2 braneworld. The recent results of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) antiproton observation imply the existence of exotic primary sub-GeV antiprotons, one of whose most probable origin is PBHs in our Galaxy. We show that the magnitude of antiproton flux from PBHs in the Randall-Sundrum braneworld is proportional to negative power of the anti-de Sitter radius and immediately find that a large extra dimension can relax upper limits on the abundance of the galactic PBHs. If actually there are more PBHs than the known upper limit obtained in the pure 4D case, they set a lower bound on the size of the extra dimension above at least 10{sup 20} times 4D Planck length to avoid inconsistency. On completion of the numerical studies, we show that these constraints on the AdS radius are comparable to those obtained from the diffuse photon background by some of the authors in the previous paper. Moreover, in the low accretion rate case, only antiprotons can constrain the braneworld. We show that we will detect signatures of the braneworld as a difference between the flux of the antiprotons predicted in 4D and 5D by future observations in sub-GeV region with a few percent precision.
NASA Astrophysics Data System (ADS)
Cieplak, Agnieszka; Griest, K.; Lehner, M.
2014-01-01
Primordial Black Holes (PBHs) remain one of the few Dark Matter (DM) candidates left within the Standard Model of Particle Physics. We have previously found that previous PBH DM limits could theoretically be extended by two orders of magnitude by using the microlensing of the source stars monitored by the Kepler satellite due to its photometric precision and the large projected cross section of the nearby stars. Here we present the experimental results of our study of the first two years of Kepler stellar lightcurves. After eliminating background events such as variable stars, flares, and comets, we have found no microlensing events. We were therefore able to calculate our efficiency of detection by introducing millions of fake microlensing events which included limb-darkening and a corrected finite-source microlensing formalism. By performing this Monte Carlo analysis, we have found that PBHs with masses between 2 × 10-9 M⊙ and 10-7 M⊙ cannot constitute the entirety of the DM, thereby constraining a full order of magnitude of the previously allowed PBH DM mass range.
NASA Astrophysics Data System (ADS)
Ghaffarnejad, H.; Neyad, H.; Mojahedi, M. A.
2013-08-01
We obtain renormalized stress tensor of a mass-less, charge-less dynamical quantum scalar field, minimally coupled with a spherically symmetric static Lukewarm black hole. In two dimensional analog the minimal coupling reduces to the conformal coupling and the stress tensor is found to be determined by the nonlocal contribution of the anomalous trace and some additional parameters in close relation to the work presented by Christensen and Fulling. Lukewarm black holes are a special class of Reissner-Nordström-de Sitter space times where its electric charge is equal to its mass. Having the obtained renormalized stress tensor we attempt to obtain a time-independent solution of the well known metric back reaction equation. Mathematical derivations predict that the final state of an evaporating quantum Lukewarm black hole reduces to a remnant stable mini black hole with moved locations of the horizons. Namely the perturbed black hole (cosmological) horizon is compressed (extended) to scales which is smaller (larger) than the corresponding classical radius of the event horizons. Hence there is not obtained an deviation on the cosmic sensor-ship hypothesis.
Information is not lost in the evaporation of 2D black holes.
Ashtekar, Abhay; Taveras, Victor; Varadarajan, Madhavan
2008-05-30
We analyze Hawking evaporation of the Callan-Giddings-Harvey-Strominger black holes from a quantum geometry perspective and show that information is not lost, primarily because the quantum space-time is sufficiently larger than the classical. Using suitable approximations to extract physics from quantum space-times we establish that (i) the future null infinity of the quantum space-time is sufficiently long for the past vacuum to evolve to a pure state in the future, (ii) this state has a finite norm in the future Fock space, and (iii) all the information comes out at future infinity; there are no remnants. PMID:18518597
A new limit on the rate-density of evaporating black holes
The CYGNUS Collaboration
1993-05-01
Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1 {times} 10{sup 5}pc{sup {minus}3}yr{sup {minus}1} at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude.
A new limit on the rate-density of evaporating black holes
Not Available
1993-01-01
Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1 [times] 10[sup 5]pc[sup [minus]3]yr[sup [minus]1] at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude.
Ori, Amos
2010-11-15
Callan, Giddings, Harvey, and Strominger (CGHS) previously introduced a two-dimensional semiclassical model of gravity coupled to a dilaton and to matter fields. Their model yields a system of field equations which may describe the formation of a black hole in gravitational collapse as well as its subsequent evaporation. Here we present an approximate analytical solution to the semiclassical CGHS field equations. This solution is constructed using the recently introduced formalism of flux-conserving hyperbolic systems. We also explore the asymptotic behavior at the horizon of the evaporating black hole.
Nonparadoxical loss of information in black hole evaporation in a quantum collapse model
NASA Astrophysics Data System (ADS)
Modak, Sujoy K.; Ortíz, Leonardo; Peña, Igor; Sudarsky, Daniel
2015-06-01
We consider a novel approach to address the black hole information paradox. The idea is based on adapting, to the situation at hand, the modified versions of quantum theory involving spontaneous stochastic dynamical collapse of quantum states, which have been considered in attempts to deal with shortcomings of the standard Copenhagen interpretation of quantum mechanics, in particular, the issue known as "the measurement problem." The new basic hypothesis is that the modified quantum behavior is enhanced in the region of high curvature so that the information encoded in the initial quantum state of the matter fields is rapidly erased as the black hole singularity is approached. We show that in this manner the complete evaporation of the black hole via Hawking radiation can be understood as involving no paradox. Calculations are performed using a modified version of quantum theory known as "continuous spontaneous localization" (CSL), which was originally developed in the context of many-particle nonrelativistic quantum mechanics. We use a version of CSL tailored to quantum field theory and applied in the context of the two -dimensional Callan-Giddings-Harvey-Strominger model. Although the role of quantum gravity in this picture is restricted to the resolution of the singularity, related studies suggest that there might be further connections.
Domination of black hole accretion in brane cosmology.
Majumdar, A S
2003-01-24
We consider the evolution of primordial black holes formed during the high energy phase of the braneworld scenario. We show that the effect of accretion from the surrounding radiation bath is dominant compared to evaporation for such black holes. This feature lasts till the onset of matter (or black hole) domination of the total energy density which could occur either in the high energy phase or later. We find that the black hole evaporation times could be significantly large even for black holes with small initial mass to survive until several cosmologically interesting eras. PMID:12570481
NASA Astrophysics Data System (ADS)
Hutchinson, John; Stojkovic, Dejan
2016-07-01
We examine the basic assumptions in the original setup of the firewall paradox. The main claim is that a single mode of the lathe radiation is maximally entangled with the mode inside the horizon and simultaneously with the modes of early Hawking radiation. We argue that this situation never happens during the evolution of a black hole. Quantum mechanics tells us that while the black hole exists, unitary evolution maximally entangles a late mode located just outside the horizon with a combination of early radiation and black hole states, instead of either of them separately. One of the reasons for this is that the black hole radiation is not random and strongly depends on the geometry and charge of the black hole, as detailed numerical calculations of Hawking evaporation clearly show. As a consequence, one can not factor out the state of the black hole. However, this extended entanglement between the black hole and modes of early and late radiation indicates that, as the black hole ages, the local Rindler horizon is modified out to macroscopic distances from the black hole. Fundamentally non-local physics nor firewalls are not necessary to explain this result. We propose an infrared mechanism called icezone that is mediated by low energy interacting modes and acts near any event horizon to entangle states separated by long distances. These interactions at first provide small corrections to the thermal Hawking radiation. At the end of evaporation however the effect of interactions is as large as the Hawking radiation and information is recovered for an outside observer. We verify this in an explicit construction and calculation of the density matrix of a spin model.
NASA Astrophysics Data System (ADS)
Alsing, P. M.; Fanto, M. L.
2016-01-01
We present an analytical formulation of the recent one-shot decoupling model of Bràdler and Adami (2015 arXiv:1505.0284) and compute the resulting 'Page information' curves, for the reduced density matrices for the evaporating black hole (BH) internal degrees of freedom, and emitted Hawking radiation pairs entangled across the horizon. We argue that BH evaporation/particle production has a very close analogy to the laboratory process of spontaneous parametric down conversion, when the pump is allowed to deplete.
Time dependent Schrödinger equation for black hole evaporation: No information loss
Corda, Christian
2015-02-15
In 1976 S. Hawking claimed that “Because part of the information about the state of the system is lost down the hole, the final situation is represented by a density matrix rather than a pure quantum state”. This was the starting point of the popular “black hole (BH) information paradox”. In a series of papers, together with collaborators, we naturally interpreted BH quasi-normal modes (QNMs) in terms of quantum levels discussing a model of excited BH somewhat similar to the historical semi-classical Bohr model of the structure of a hydrogen atom. Here we explicitly write down, for the same model, a time dependent Schrödinger equation for the system composed by Hawking radiation and BH QNMs. The physical state and the correspondent wave function are written in terms of a unitary evolution matrix instead of a density matrix. Thus, the final state results to be a pure quantum state instead of a mixed one. Hence, Hawking’s claim is falsified because BHs result to be well defined quantum mechanical systems, having ordered, discrete quantum spectra, which respect ’t Hooft’s assumption that Schrödinger equations can be used universally for all dynamics in the universe. As a consequence, information comes out in BH evaporation in terms of pure states in a unitary time dependent evolution. In Section 4 of this paper we show that the present approach permits also to solve the entanglement problem connected with the information paradox.
Smoot, G.F.
1981-07-01
Large-angular-scale anisotropies in the 3 K primordial black-body radiation were detected and mapped with a sensitivity of 2 x to the minus 4 power K and an angular resolution of about 10 deg. The motion of the Earth with respect to the distant matter of the Universe ( Aether Drift ) was measured and the homogeneity and isotropy of the Universe (the Cosmological Principle ) was probed. The experiment uses two Dicke radiometers, one at 33 GHz to detect the cosmic anisotropy, and one at 54 GHz to detect anisotropies in the residual oxygen above the detectors. The system was installed in the NASA-Ames Earth survey aircraft (U-2), and operated successfully in a series of flights in both the Northern and Southern Hemispheres. Data taking and analysis to measure the anisotropy were successful.
NASA Astrophysics Data System (ADS)
Coc, A.
2016-01-01
Primordial nucleosynthesis, or Big Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor ≈3, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe.
Liu, Yiming; Chen, Jingwei; Guo, Dawei; Cao, Moyuan; Jiang, Lei
2015-06-24
Efficient solar evaporation plays an indispensable role in nature as well as the industry process. However, the traditional evaporation process depends on the total temperature increase of bulk water. Recently, localized heating at the air-water interface has been demonstrated as a potential strategy for the improvement of solar evaporation. Here, we show that the carbon-black-based superhydrophobic gauze was able to float on the surface of water and selectively heat the surface water under irradiation, resulting in an enhanced evaporation rate. The fabrication process of the superhydrophobic black gauze was low-cost, scalable, and easy-to-prepare. Control experiments were conducted under different light intensities, and the results proved that the floating black gauze achieved an evaporation rate 2-3 times higher than that of the traditional process. A higher temperature of the surface water was observed in the floating gauze group, revealing a main reason for the evaporation enhancement. Furthermore, the self-cleaning ability of the superhydrophobic black gauze enabled a convenient recycling and reusing process toward practical application. The present material may open a new avenue for application of the superhydrophobic substrate and meet extensive requirements in the fields related to solar evaporation. PMID:26027770
Schramm, David N.
1998-01-01
With the advent of the new extragalactic deuterium observations, Big Bang nucleosynthesis (BBN) is on the verge of undergoing a transformation. In the past, the emphasis has been on demonstrating the concordance of the BBN model with the abundances of the light isotopes extrapolated back to their primordial values by using stellar and galactic evolution theories. As a direct measure of primordial deuterium is converged upon, the nature of the field will shift to using the much more precise primordial D/H to constrain the more flexible stellar and galactic evolution models (although the question of potential systematic error in 4He abundance determinations remains open). The remarkable success of the theory to date in establishing the concordance has led to the very robust conclusion of BBN regarding the baryon density. This robustness remains even through major model variations such as an assumed first-order quark-hadron phase transition. The BBN constraints on the cosmological baryon density are reviewed and demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. Comparison of baryonic density arguments from Lyman-α clouds, x-ray gas in clusters, and the microwave anisotropy are made. PMID:9419322
Schramm, D N
1998-01-01
With the advent of the new extragalactic deuterium observations, Big Bang nucleosynthesis (BBN) is on the verge of undergoing a transformation. In the past, the emphasis has been on demonstrating the concordance of the BBN model with the abundances of the light isotopes extrapolated back to their primordial values by using stellar and galactic evolution theories. As a direct measure of primordial deuterium is converged upon, the nature of the field will shift to using the much more precise primordial D/H to constrain the more flexible stellar and galactic evolution models (although the question of potential systematic error in 4He abundance determinations remains open). The remarkable success of the theory to date in establishing the concordance has led to the very robust conclusion of BBN regarding the baryon density. This robustness remains even through major model variations such as an assumed first-order quark-hadron phase transition. The BBN constraints on the cosmological baryon density are reviewed and demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. Comparison of baryonic density arguments from Lyman-alpha clouds, x-ray gas in clusters, and the microwave anisotropy are made. PMID:9419322
NASA Astrophysics Data System (ADS)
Van Raamsdonk, Mark
2014-11-01
In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.
A new mass scale, implications on black hole evaporation and holography
NASA Astrophysics Data System (ADS)
Burikham, Piyabut; Dhanawittayapol, Rujikorn; Wuthicharn, Taum
2016-06-01
We consider a new mass scale MT = (ℏ2Λ/G)1/3 constructed from dimensional analysis by using G, ℏ and Λ and discuss its physical interpretation. Based on the Generalized Uncertainty Relation, a black hole with age comparable to the universe would stop radiating when the mass reaches a new mass scale MT‧ = c(ℏ/G2Λ)1/3 at which its temperature corresponds to the mass MT. Black hole remnants could have masses ranging from a Planck mass to a trillion kilograms. Holography persists even when the uncertainty relation is modified to the Minimum Length Uncertainty Relation (MLUR). The remnant black hole entropy is proportional to the surface area of the black hole in unit of the Planck area in arbitrary noncompact dimensions.
Gauss-bonnet black holes and possibilities for their experimental search
Alexeyev, S. O. Rannu, K. A.
2012-03-15
Corollaries of gravity models with second-order curvature corrections in the form of a Gauss-Bonnet term and possibilities (or impossibilities) for their experimental search or observations are discussed. The full version of the four-dimensional Schwarzschild-Gauss-Bonnet black hole solution and the constraint on the possible minimal black hole mass following from this model are considered. Using our solution as a model for the final stages of Hawking evaporation of black holes with a low initial mass (up to 10{sup 15} g) whose lifetime is comparable to that of our Universe, we have revealed differences in the patterns of evaporation: we have obtained high values of the emitted energy and showed the impossibility of an experimental search for primordial black holes by their evaporation products. Scenarios for the evaporation of Gauss-Bonnet black holes in multidimensional gravity models and possibilities for their experimental search are also discussed.
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation
NASA Astrophysics Data System (ADS)
Brádler, Kamil; Adami, Christoph
2016-03-01
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum.
One-Shot Decoupling and Page Curves from a Dynamical Model for Black Hole Evaporation.
Brádler, Kamil; Adami, Christoph
2016-03-11
One-shot decoupling is a powerful primitive in quantum information theory and was hypothesized to play a role in the black hole information paradox. We study black hole dynamics modeled by a trilinear Hamiltonian whose semiclassical limit gives rise to Hawking radiation. An explicit numerical calculation of the discretized path integral of the S matrix shows that decoupling is exact in the continuous limit, implying that quantum information is perfectly transferred from the black hole to radiation. A striking consequence of decoupling is the emergence of an output radiation entropy profile that follows Page's prediction. We argue that information transfer and the emergence of Page curves is a robust feature of any multilinear interaction Hamiltonian with a bounded spectrum. PMID:27015471
NASA Astrophysics Data System (ADS)
Cutchin, Sean E.; Simonetti, John H.; Ellingson, Steven W.; Larracuente, Amanda S.; Kavic, Michael J.
2015-12-01
An exploding primordial black hole (PBH) may produce a single pulse of electromagnetic radiation detectable at the low-frequency end of the radio spectrum. Furthermore, a radio transient from an exploding PBH could be a signature of an extra spatial dimension. We describe here an approach for searching for PBH explosions using a low-frequency radio antenna array, and as a practical example, the results of such a search using the Eight-meter-wavelength Transient Array (ETA). No compelling astrophysical signal was detected in ≈4 hr of data, implying an observational upper limit on the rate of exploding PBHs is 2.3 × 10-7 pc-3 yr-1 for an exploding PBH with a fireball Lorentz factor of 104.3 for the standard scenario of Page and Hawking. This rate limit is the strongest constraint yet set for PBH explosions with this fireball Lorentz factor. Observations (~300 hr) using the Arecibo Observatory were used to set a stronger constraint on the rate of PBH explosions for a fireball Lorentz factor of 104.6, but the limit set by those observations for the fireball Lorentz factor considered here are less stringent by more than an order of magnitude. The limits considered here are applicable to exploding PBHs in the halo of the Galaxy. These observations also imply an upper limit of 2.3 × 10-4 pc-3 yr-1 on the rate of PBH explosions in the context of certain extra dimension models, as described by Kavic et al. This rate limit is for a fireball Lorentz factor of 104.3, which corresponds to an extra dimension compactification scale of 5.0 × 10-18 m.
Tunneling of squeezed states with an eye to evaporating black holes
NASA Astrophysics Data System (ADS)
Kontou, Eleni-Alexandra; Haggard, Hal
2016-03-01
In this work we study how tunneling time depends on the squeezing parameter of quantum states. Squeezed quantum states are investigated for optical communications and appear in the emission from black holes. A surprising property of these states is reduced tunneling time. Treating Hawking radiation as a quantum tunneling process, we study the interplay of squeezing with the radiation process.
Time dependent Schrödinger equation for black hole evaporation: No information loss
NASA Astrophysics Data System (ADS)
Corda, Christian
2015-02-01
In 1976 S. Hawking claimed that "Because part of the information about the state of the system is lost down the hole, the final situation is represented by a density matrix rather than a pure quantum state".1 In a series of papers, together with collaborators, we naturally interpreted BH quasi-normal modes (QNMs) in terms of quantum levels discussing a model of excited BH somewhat similar to the historical semi-classical Bohr model of the structure of a hydrogen atom. Here we explicitly write down, for the same model, a time dependent Schrödinger equation for the system composed by Hawking radiation and BH QNMs. The physical state and the correspondent wave function are written in terms of a unitary evolution matrix instead of a density matrix. Thus, the final state results to be a pure quantum state instead of a mixed one. Hence, Hawking's claim is falsified because BHs result to be well defined quantum mechanical systems, having ordered, discrete quantum spectra, which respect 't Hooft's assumption that Schrödinger equations can be used universally for all dynamics in the universe. As a consequence, information comes out in BH evaporation in terms of pure states in a unitary time dependent evolution. In Section 4 of this paper we show that the present approach permits also to solve the entanglement problem connected with the information paradox.
NASA Astrophysics Data System (ADS)
Gustavino, C.; Anders, M.; Bemmerer, D.; Elekes, Z.; Trezzi, D.
2016-04-01
Big Bang nucleosynthesis (BBN) describes the production of light nuclei in the early phases of the Universe. For this, precise knowledge of the cosmological parameters, such as the baryon density, as well as the cross section of the fusion reactions involved are needed. In general, the energies of interest for BBN are so low ( E < 1MeV) that nuclear cross section measurements are practically unfeasible at the Earth's surface. As of today, LUNA (Laboratory for Underground Nuclear Astrophysics) has been the only facility in the world available to perform direct measurements of small cross section in a very low background radiation. Owing to the background suppression provided by about 1400 meters of rock at the Laboratori Nazionali del Gran Sasso (LNGS), Italy, and to the high current offered by the LUNA accelerator, it has been possible to investigate cross sections at energies of interest for Big Bang nucleosynthesis using protons, 3He and alpha particles as projectiles. The main reaction studied in the past at LUNA is the 2H(4He, γ)6Li . Its cross section was measured directly, for the first time, in the BBN energy range. Other processes like 2H(p, γ)3He , 3He(2H, p)4He and 3He(4He, γ)7Be were also studied at LUNA, thus enabling to reduce the uncertainty on the overall reaction rate and consequently on the determination of primordial abundances. The improvements on BBN due to the LUNA experimental data will be discussed and a perspective of future measurements will be outlined.
Kunze, Kerstin E.
2014-01-01
Primordial magnetic fields that exist before the photon-baryon decoupling epoch are damped on length scales below the photon diffusion and free-streaming scales. The energy injected into the plasma by dissipation of magnetosonic and Alfv and apos;en waves heats photons, creating a y-type distortion of the black-body spectrum of the cosmic microwave background. This y-type distortion is converted into a μ-type distortion when elastic Compton scattering is efficient. Therefore, we can use observational limits on y- and μ-type distortions to constrain properties of magnetic fields in the early universe. Assuming a Gaussian, random, and non-helical field, we calculate μ and y as a function of the present-day strength of the field, B{sub 0}, smoothed over a certain Gaussian width, k{sub c}{sup −1}, as well as of the spectral index of the power spectrum of fields, n{sub B}, defined by P{sub B}(k)∝k{sup n{sub B}}. For a nearly scale-invariant spectrum with n{sub B} = −2.9 and a Gaussian smoothing width of k{sub c}{sup −1} = 1Mpc, the existing COBE/FIRAS limit on μ yields B{sub 0} < 40 nG, whereas the projected PIXIE limit on μ would yield B{sub 0} < 0.8 nG. For non-scale-invariant spectra, constraints can be stronger. For example, for B{sub 0} = 1 nG with k{sub c}{sup −1} = 1Mpc, the COBE/FIRAS limit on μ excludes a wide range of spectral indices given by n{sub B} > −2.6. After decoupling, energy dissipation is due to ambipolar diffusion and decaying MHD turbulence, creating a y-type distortion. The distortion is completely dominated by decaying MHD turbulence, and is of order y ≈ 10{sup −7} for a few nG field smoothed over the damping scale at the decoupling epoch, k{sub d,} {sub dec} ≈ 290(B{sub 0}/1nG){sup −1}Mpc{sup −1}. The projected PIXIE limit on y would exclude B{sub 0} > 1.0 and 0.6 nG for n{sub B} = −2.9 and -2.3, respectively, and B{sub 0} > 0.6 nG for n{sub B} ≥ 2. Finally, we find that the current limits on the optical depth to
Black Hole Hawking Radiation May Never Be Observed!
NASA Astrophysics Data System (ADS)
Sivaram, C.
2001-02-01
Thermal Hawking emission from black holes is a remarkable consequence of the unification of quantum physics and gravitation. Black holes of a few solar masses are the only ones which can form in the present universe. However, having temperatures million times smaller than the ambient cosmic background radiation they cannot evaporate. Primordial black holes of M ˜ 1014g would evaporate over a Hubble age and considerable ongoing effort is on to detect such explosions. I point out, however, that at the early universe epochs when such black holes form, the ambient radiation temperature considerably exceeds their corresponding Hawking temperature. This results in rapid continual accretion (absorption) of ambient radiation by these holes. Consequently by the end of the radiation era their masses grow much greater so that their lifetimes (scaling as M3) would now be enormously greater than the Hubble age implying undetectably small emission.
Primordial nuggets survival and QCD pairing
NASA Astrophysics Data System (ADS)
Lugones, G.; Horvath, J. E.
2004-03-01
We reexamine the problem of boiling and surface evaporation of quark nuggets in the cosmological quark-hadron transition with the explicit consideration of pairing between quarks in a color-flavor locked state. Assuming that primordial quark nuggets are actually formed, we analyze the consequences of pairing on the rates of boiling and surface evaporation in order to determine whether they could have survived with substantial mass. We find a substantial quenching of the evaporation+boiling processes, which suggests the survival of primordial nuggets for the currently considered range of the pairing gap Δ. Boiling is shown to depend on the competition of an increased stability window and the suppression of the rate, and is not likely to dominate the destruction of the nuggets. If surface evaporation dominates, the fate of the nuggets depends on the features of the initial mass spectrum of the nuggets, their evaporation rate, and the value of the pairing gap, as shown and discussed in the text.
Liu; Yuan; Meyer; Meyer-Hofmeister; Xie
1999-12-10
We apply the disk-corona evaporation model (Meyer & Meyer-Hofmeister) originally derived for dwarf novae to black hole systems. This model describes the transition of a thin cool outer disk to a hot coronal flow. The mass accretion rate determines the location of this transition. For a number of well-studied black hole binaries, we take the mass flow rates derived from a fit of the advection-dominated accretion flow (ADAF) model to the observed spectra (for a review, see Narayan, Mahadevan, & Quataert) and determine where the transition of accretion via a cool disk to a coronal flow/ADAF would be located for these rates. We compare this with the observed location of the inner disk edge, as estimated from the maximum velocity of the Halpha emission line. We find that the transition caused by evaporation agrees with this determination in stellar disks. We also show that the ADAF and the "thin outer disk + corona" are compatible in terms of the physics in the transition region. PMID:10566989
Effect of curvaton decay on the primordial power spectrum
NASA Astrophysics Data System (ADS)
Firouzjahi, Hassan; Green, Anne M.; Malik, Karim A.; Zarei, Moslem
2013-05-01
We study the effect of curvaton decay on the primordial power spectrum. Using analytical approximations and also numerical calculations, we find that the power spectrum is enhanced during the radiation dominated era after the curvaton decay. The amplitude of the Bardeen potential is controlled by the fraction of the energy density in the curvaton at the time of curvaton decay. We show that the enhancement in the amplitude of the primordial curvature perturbation is, however, not large enough to lead to primordial black hole overproduction on scales which reenter the horizon after the time of curvaton decay.
Technology Transfer Automated Retrieval System (TEKTRAN)
Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...
NASA Astrophysics Data System (ADS)
Luminet, Jean-Pierre
1992-09-01
Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.
Primordial nucleosynthesis redux
NASA Technical Reports Server (NTRS)
Walker, Terry P.; Steigman, Gary; Kang, Ho-Shik; Schramm, David M.; Olive, Keith A.
1991-01-01
The abundances of D, He-3, He-4, and Li-7, are presently recalculated within the framework of primordial nucleosynthesis in the standard hot big band model, in order to estimate the primordial abundances of the light elements. A comparison between theory and experiment demonstrates the consistency of standard model predictions; the baryon density parameter is constrained on the basis of a nucleon-to-photon ratio of 2.8-4.0. These bounds imply that the bulk of the baryons in the universe are dark, requiring that the universe be dominated by nonbaryonic matter.
Searching for Primordial Antimatter
NASA Astrophysics Data System (ADS)
2008-10-01
Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot
Searching for Primordial Antimatter
NASA Astrophysics Data System (ADS)
2008-10-01
Scientists are on the hunt for evidence of antimatter - matter's arch nemesis - leftover from the very early Universe. New results using data from NASA's Chandra X-ray Observatory and Compton Gamma Ray Observatory suggest the search may have just become even more difficult. Antimatter is made up of elementary particles, each of which has the same mass as their corresponding matter counterparts --protons, neutrons and electrons -- but the opposite charges and magnetic properties. When matter and antimatter particles collide, they annihilate each other and produce energy according to Einstein's famous equation, E=mc2. According to the Big Bang model, the Universe was awash in particles of both matter and antimatter shortly after the Big Bang. Most of this material annihilated, but because there was slightly more matter than antimatter - less than one part per billion - only matter was left behind, at least in the local Universe. Trace amounts of antimatter are believed to be produced by powerful phenomena such as relativistic jets powered by black holes and pulsars, but no evidence has yet been found for antimatter remaining from the infant Universe. How could any primordial antimatter have survived? Just after the Big Bang there was believed to be an extraordinary period, called inflation, when the Universe expanded exponentially in just a fraction of a second. "If clumps of matter and antimatter existed next to each other before inflation, they may now be separated by more than the scale of the observable Universe, so we would never see them meet," said Gary Steigman of The Ohio State University, who conducted the study. "But, they might be separated on smaller scales, such as those of superclusters or clusters, which is a much more interesting possibility." X-rayChandra X-ray Image In that case, collisions between two galaxy clusters, the largest gravitationally-bound structures in the Universe, might show evidence for antimatter. X-ray emission shows how much hot
Grzanka, R.
1997-12-31
This paper reports on an intriguing pilot project developed to control air emissions from a pulp mill. Testing is complete, and the results show favorable emissions reductions. Stone Container Corporation, REECO, NCASI, the Ohio DEP, and the US EPA, have all worked together and approved the installation of control equipment, for VOC and HAP emissions under Presumptive MACT, setting the standard for the Copeland Reactor process in a semi chem pulp mill. The equipment, once operational, will reduce VOC and CO emissions by greater than 90%. This installation will be done at one seventh the cost of the significant process modifications required to accomplish the same emission reduction. In addition, increased process operating efficiency will be achieved with the use of an energy recovery system. The process is a black liquor fluidized bed boiler, which is used to generate sodium carbonate from the black liquor. The vapor emissions were high in VOCs, CO and particulate. After much study and testing, a wet electrostatic precipitator was chosen as the filter system for particulate control, followed by a regenerative thermal oxidizer for VOC and HAP control, finally an air-to-air heat exchanger is being used to preheat the combustion air entering the process.
NASA Astrophysics Data System (ADS)
Sazonov, S.; Sunyaev, R.
2015-12-01
The 21-cm signal from the cosmic reionization epoch can shed light on the history of heating of the primordial intergalactic medium (IGM) at z ˜ 30-10. It has been suggested that X-rays from the first accreting black holes could significantly heat the Universe at these early epochs. Here we propose another IGM heating mechanism associated with the first stars. As known from previous work, the remnants of powerful supernovae (SNe) ending the lives of massive Population III stars could readily expand out of their host dark matter minihaloes into the surrounding IGM, aided by the preceding photo-evaporation of the halo's gas by the UV radiation from the progenitor star. We argue that during the evolution of such a remnant, a significant fraction of the SN kinetic energy can be put into low-energy (E ≲ 30 MeV) cosmic rays that will eventually escape into the IGM. These subrelativistic cosmic rays could propagate through the Universe and heat the IGM by ˜10-100 K by z ˜ 15, before more powerful reionization/heating mechanisms associated with the first galaxies and quasars came into play. Future 21-cm observations could thus constrain the energetics of the first SNe and provide information on the magnetic fields in the primordial IGM.
Primordial material in meteorites
NASA Technical Reports Server (NTRS)
Kerridge, J. F.
1986-01-01
Primordial is a term which applied to material that entered the solar system early and became incorporated into a meteorite without totally losing its identity. Identification of such material surviving in meteorites is so far solely through recognition of anomalous isotopic compositions of generally macroscopic entities contained within those meteorites. Isotopic anomalies are, by definition, isotopic compositions which differ from the canonical solar system abundances in ways which cannot be explained in terms of local processes such as mass dependent fractionation, cosmic ray induced spallation or decay of radionuclides. A comprehensive account of isotopic anomalies is impractical here, so it is necessary to be selective. Issues which are potentially addressable through the study of such primordial material are examined. Those issues will be illustrated with specific, but not exhaustive, examples.
The Primordial Inflation Explorer
NASA Technical Reports Server (NTRS)
Kogut, Alan J.
2012-01-01
The Primordial Inflation Explorer is an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10(exp -3) at 5 standard deviations. The rich PIXIE data set will also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy. I describe the PIXIE instrument and mission architecture needed to detect the inflationary signature using only 4 semiconductor bolometers.
Semiclassical geons as solitonic black hole remnants
Lobo, Francisco S.N.; Olmo, Gonzalo J.; Rubiera-Garcia, D. E-mail: gonzalo.olmo@csic.es
2013-07-01
We find that the end state of black hole evaporation could be represented by non-singular and without event horizon stable solitonic remnants with masses of the order the Planck scale and up to ∼ 16 units of charge. Though these objects are locally indistinguishable from spherically symmetric, massive electric (or magnetic) charges, they turn out to be sourceless geons containing a wormhole generated by the electromagnetic field. Our results are obtained by interpreting semiclassical corrections to Einstein's theory in the first-order (Palatini) formalism, which yields second-order equations and avoids the instabilities of the usual (metric) formulation of quadratic gravity. We also discuss the potential relevance of these solutions for primordial black holes and the dark matter problem.
Extracting primordial density fluctuations
Gawiser; Silk
1998-05-29
The combination of detections of anisotropy in cosmic microwave background radiation and observations of the large-scale distribution of galaxies probes the primordial density fluctuations of the universe on spatial scales varying by three orders of magnitude. These data are found to be inconsistent with the predictions of several popular cosmological models. Agreement between the data and the cold + hot dark matter model, however, suggests that a significant fraction of the matter in the universe may consist of massive neutrinos. PMID:9603724
Physics of primordial star formation
NASA Astrophysics Data System (ADS)
Yoshida, Naoki
2012-09-01
The study of primordial star formation has a history of nearly sixty years. It is generally thought that primordial stars are one of the key elements in a broad range of topics in astronomy and cosmology, from Galactic chemical evolution to the formation of super-massive blackholes. We review recent progress in the theory of primordial star formation. The standard theory of cosmic structure formation posits that the present-day rich structure of the Universe developed through gravitational amplification of tiny matter density fluctuations left over from the Big Bang. It has become possible to study primordial star formation rigorously within the framework of the standard cosmological model. We first lay out the key physical processes in a primordial gas. Then, we introduce recent developments in computer simulations. Finally, we discuss prospects for future observations of the first generation of stars.
Primordial features and Planck polarization
NASA Astrophysics Data System (ADS)
Hazra, Dhiraj Kumar; Shafieloo, Arman; Smoot, George F.; Starobinsky, Alexei A.
2016-09-01
With the Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization data, we search for possible features in the primordial power spectrum (PPS). We revisit the Wiggly Whipped Inflation (WWI) framework and demonstrate how generation of some particular primordial features can improve the fit to Planck data. WWI potential allows the scalar field to transit from a steeper potential to a nearly flat potential through a discontinuity either in potential or in its derivatives. WWI offers the inflaton potential parametrizations that generate a wide variety of features in the primordial power spectra incorporating most of the localized and non-local inflationary features that are obtained upon reconstruction from temperature and polarization angular power spectrum. At the same time, in a single framework it allows us to have a background parameter estimation with a nearly free-form primordial spectrum. Using Planck 2015 data, we constrain the primordial features in the context of Wiggly Whipped Inflation and present the features that are supported both by temperature and polarization. WWI model provides more than 13 improvement in χ2 fit to the data with respect to the best fit power law model considering combined temperature and polarization data from Planck and B-mode polarization data from BICEP and Planck dust map. We use 2-4 extra parameters in the WWI model compared to the featureless strict slow roll inflaton potential. We find that the differences between the temperature and polarization data in constraining background cosmological parameters such as baryon density, cold dark matter density are reduced to a good extent if we use primordial power spectra from WWI. We also discuss the extent of bispectra obtained from the best potentials in arbitrary triangular configurations using the BI-spectra and Non-Gaussianity Operator (BINGO).
NASA Technical Reports Server (NTRS)
Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, S. F.
1998-01-01
Evaporation is the consequence of heating near the top of streamers in ideal Magnetohydrodynamics (MHD) models, where the plasma is weakly contained by the magnetic field. Heating causes slow opening of field lines and release of new solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because there are losses by thermal conduction and radiation. Physically, heating is also expected to depend on ambient conditions. We use our global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also apply and extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than approximately 2 x 10(exp 6) K.
NASA Technical Reports Server (NTRS)
Shen, Hayley H.
1991-01-01
Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.
Primordial Blackhole as a Seed for the Cosmic Magnetic Field
NASA Astrophysics Data System (ADS)
La, Dail; Park, Changbom
1996-10-01
We present a model that rotating primordial blackholes(PBHs) produced at the end of inflation generate the random, non-oriented primordial magnetic field. PBHs are copiously produced as the Universe completes the cosmic phase transition via bubble nucleation and tunneling processes in the extended inflation hypothesis. The PBHs produced acquire angular momentum through the mutual tidal gravitational interaction. For PBHs of mass less than 10E13 g, one can show that the evaporation (photon) luminosity of PBHs exceeds the Eddington limit. Thus throughout the lifetime of the rotating PBH, radiation flow from the central blackhole along the Kerr-geodesic exerts torque to ambient plasma. In the process similar to the Bierman's battery mechanism electron current reaching up to the horizon scale is induced. For PBHs of Grand Unified Theories extended inflation with the symmetry breaking temperature of Tgut ~ 10E10 GeV, which evaporate near decoupling, we find that they generate random, non-oriented magnetic fields of about 10E-11 G on the last-scattering surface on (the present comoving) scales of about O(10) Mpc.
Cosmic superstrings and primordial magnetogenesis
Davis, Anne-Christine; Dimopoulos, Konstantinos
2005-08-15
Cosmic superstrings are produced at the end of brane inflation. Their properties are similar to cosmic strings arising in grand unified theories. Like cosmic strings they can give rise to a primordial magnetic field, as a result of vortical motions stirred in the ionized plasma by the gravitational pull of moving string segments. The resulting magnetic field is both strong enough and coherent enough to seed the galactic dynamo and explain the observed magnetic fields of the galaxies.
Primordial power spectrum from Planck
NASA Astrophysics Data System (ADS)
Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun
2014-11-01
Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra from Planck to reconstruct the shape of the primordial power spectrum and locate possible features. Performing an extensive error analysis we found the dip near l ~ 750-850 represents the most prominent feature in the data. Feature near l ~ 1800-2000 is detectable with high confidence only in 217 GHz spectrum and is apparently consequence of a small systematic as described in the revised Planck 2013 papers. Fixing the background cosmological parameters and the foreground nuisance parameters to their best fit baseline values, we report that the best fit power law primordial power spectrum is consistent with the reconstructed form of the PPS at 2σ C.L. of the estimated errors (apart from the local features mentioned above). As a consistency test, we found the reconstructed primordial power spectrum from Planck temperature data can also substantially improve the fit to WMAP-9 angular power spectrum data (with respect to power-law form of the PPS) allowing an overall amplitude shift of ~ 2.5%. In this context low-l and 100 GHz spectrum from Planck which have proper overlap in the multipole range with WMAP data found to be completely consistent with WMAP-9 (allowing amplitude shift). As another important result of our analysis we do report the evidence of gravitational lensing through the reconstruction analysis. Finally we present two smooth form of the PPS containing only the important features. These smooth forms of PPS can provide significant improvements in fitting the data (with respect to the power law PPS) and can be helpful to give hints for inflationary model building.
Lunar magnetism. [primordial core model
NASA Technical Reports Server (NTRS)
Goldstein, M. L.
1975-01-01
It is shown, for a very simple model of the moon, that the existence of a primordial core magnetic field would give rise to a present day nonzero dipole external field. In the investigation a uniformly magnetized core embedded in a permeable mantle is considered. The significance of the obtained results for the conclusions reported by Runcorn (1975) is discussed. Comments provided by Runcorn to the discussion are also presented.
Primordial power spectrum from Planck
Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun E-mail: arman@apctp.org
2014-11-01
Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra from Planck to reconstruct the shape of the primordial power spectrum and locate possible features. Performing an extensive error analysis we found the dip near ℓ ∼ 750–850 represents the most prominent feature in the data. Feature near ℓ ∼ 1800–2000 is detectable with high confidence only in 217 GHz spectrum and is apparently consequence of a small systematic as described in the revised Planck 2013 papers. Fixing the background cosmological parameters and the foreground nuisance parameters to their best fit baseline values, we report that the best fit power law primordial power spectrum is consistent with the reconstructed form of the PPS at 2σ C.L. of the estimated errors (apart from the local features mentioned above). As a consistency test, we found the reconstructed primordial power spectrum from Planck temperature data can also substantially improve the fit to WMAP-9 angular power spectrum data (with respect to power-law form of the PPS) allowing an overall amplitude shift of ∼ 2.5%. In this context low-ℓ and 100 GHz spectrum from Planck which have proper overlap in the multipole range with WMAP data found to be completely consistent with WMAP-9 (allowing amplitude shift). As another important result of our analysis we do report the evidence of gravitational lensing through the reconstruction analysis. Finally we present two smooth form of the PPS containing only the important features. These smooth forms of PPS can provide significant improvements in fitting the data (with respect to the power law PPS) and can be helpful to give hints for inflationary model building.
Primordial nucleosynthesis with generic particles
NASA Technical Reports Server (NTRS)
Walker, T. P.; Kolb, E. W.; Turner, M. S.
1986-01-01
A revision of the standard model for Big Bang nucleosynthesis is discussed which allows for the presence of generic particle species. The primordial production of He-4 and D + He-3 is calculated as a function of the mass, spin degrees of freedom, and spin statistics of the generic particle for masses in the range 0.01-100 times the electron mass. The particular case of the Gelmini and Roncadelli majoron model for massive neutrinos is discussed.
NASA Technical Reports Server (NTRS)
Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.
1998-01-01
Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.
Black holes, pregalactic stars, and the dark matter problem
Carr, B.J.
1985-06-01
We review the different ways in which black holes might form and discuss their various astrophysical and cosmological consequences. We then consider the various constraints on the form of the dark matter and conclude that black holes could have a significant cosmological density only if they are of primordial origin or remnants of a population of pregalactic stars. This leads us to discuss the other cosmological effects of primordial black holes and pregalactic stars. 239 refs., 7 figs., 5 tabs.
Dynamical evolution of primordial dark matter haloes through mergers
NASA Astrophysics Data System (ADS)
Ogiya, Go; Nagai, Daisuke; Ishiyama, Tomoaki
2016-09-01
Primordial dark matter (DM) haloes are the smallest gravitationally bound DM structures from which the first stars, black holes and galaxies form and grow in the early universe. However, their structures are sensitive to the free streaming scale of DM, which in turn depends on the nature of DM particles. In this work, we test the hypothesis that the slope of the central cusps in primordial DM haloes near the free streaming scale depends on the nature of merging process. By combining and analysing data from a cosmological simulation with the cutoff in the small-scale matter power spectrum as well as a suite of controlled, high-resolution simulations of binary mergers, we find that (1) the primordial DM haloes form preferentially through major mergers in radial orbits; (2) their central DM density profile is more susceptible to a merging process compared to that of galaxy- and cluster-sized DM haloes; (3) consecutive major mergers drive the central density slope to approach the universal form characterized by the Navarro-Frenk-White profile, which is shown to be robust to the impacts of mergers and serves an attractor solution for the density structure of DM haloes. Our work highlights the importance of dynamical processes on the structure formation during the Dark Ages.
Resonant primordial gravitational waves amplification
NASA Astrophysics Data System (ADS)
Lin, Chunshan; Sasaki, Misao
2016-01-01
We propose a mechanism to evade the Lyth bound in models of inflation. We minimally extend the conventional single-field inflation model in general relativity (GR) to a theory with non-vanishing graviton mass in the very early universe. The modification primarily affects the tensor perturbation, while the scalar and vector perturbations are the same as the ones in GR with a single scalar field at least at the level of linear perturbation theory. During the reheating stage, the graviton mass oscillates coherently and leads to resonant amplification of the primordial tensor perturbation. After reheating the graviton mass vanishes and we recover GR.
H dibaryons and primordial nucleosynthesis
NASA Astrophysics Data System (ADS)
de Freitas Pacheco, J. A.; Stoica, S.; Thévenin, F.; Horvath, J. E.
1999-01-01
The apparent discrepancy between abundances of light nuclides predicted by the standard big bang and observational data is explained by assuming the presence of metastable H dibaryons at the nucleosynthesis era. These dibaryons could be formed out of a small fraction of strange quarks at the moment of the confinement transition. For a primordial deuterium abundance of the order of 3×10-5, the measured differences in the 4He abundances requires a relative abundance of H dibaryons of the order of nH/nB~0.07, decaying in a time scale of the order of 105 s.
Primordial gravitational waves and cosmology.
Krauss, Lawrence M; Dodelson, Scott; Meyer, Stephan
2010-05-21
The observation of primordial gravitational waves could provide a new and unique window on the earliest moments in the history of the universe and on possible new physics at energies many orders of magnitude beyond those accessible at particle accelerators. Such waves might be detectable soon, in current or planned satellite experiments that will probe for characteristic imprints in the polarization of the cosmic microwave background, or later with direct space-based interferometers. A positive detection could provide definitive evidence for inflation in the early universe and would constrain new physics from the grand unification scale to the Planck scale. PMID:20489015
The Primordial Inflation Explorer (PIXIE)
NASA Technical Reports Server (NTRS)
Kogut, Alan J.
2011-01-01
The Primordial Inflation Explorer is an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded non-imaging optics feed a polarizing Fourier Transform Spectrometer to produce a set of interference fringes, proportional to the difference spectrum between orthogonal linear polarizations from the two input beams. The differential design and multiple signal modulations spanning 11 orders of magnitude in time combine to reduce the instrumental signature and confusion from unpolarized sources to negligible levels. PIXIE will map the full sky in Stokes I, Q, and U parameters with angular resolution 2.6 deg and sensitivity 0.2 uK per 1 deg square pixel. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r <10(exp -3) at 5 standard deviations. In addition, the rich PIXIE data will constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to the physical conditions within the interstellar medium of the Galaxy. We describe the PIXIE instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.
The Primordial Inflation Explorer (PIXIE)
NASA Technical Reports Server (NTRS)
Kogut, Alan; Chuss, David T.; Dotson, Jessie; Dwek, Eli; Fixsen, Dale J.; Halpern, Mark; Hinshaw, Gary F.; Meyer, Stephan; Moseley, S. Harvey; Seiffert, Michael D.; Spergel, David N.; Wollack, Edward J.
2014-01-01
The Primordial Inflation Explorer is an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded non-imaging optics feed a polarizing Fourier Transform Spectrometer to produce a set of interference fringes, proportional to the difference spectrum between orthogonal linear polarizations from the two input beams. Multiple levels of symmetry and signal modulation combine to reduce the instrumental signature and confusion from unpolarized sources to negligible levels. PIXIE will map the full sky in Stokes I, Q, and U parameters with angular resolution 2.6 deg and sensitivity 0.2 µK per 1 deg square pixel. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r less than 10(exp -3) at 5 standard deviations. In addition, PIXIE will measure the absolute frequency spectrum to constrain physical processes ranging from inflation to the nature of the first stars to the physical conditions within the interstellar medium of the Galaxy. We describe the PIXIE instrument and mission architecture with an emphasis on the expected level of systematic error suppression.
PIPER: Primordial Inflation Polarization Explorer
NASA Astrophysics Data System (ADS)
Lazear, Justin; Ade, P.; Benford, D. J.; Bennett, C. L.; Chuss, D. T.; Dotson, J. L.; Eimer, J.; Fixsen, D. J.; Halpern, M.; Hinderks, J.; Hinshaw, G. F.; Irwin, K. D.; Jhabvala, C. A.; Johnson, B.; Kogut, A. J.; Mirel, P.; Moseley, S. H.; Staguhn, J.; Tucker, C.; Weston, A.; Wollack, E.
2013-01-01
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne instrument to measure the polarization of the cosmic microwave background in search of the expected signature of primordial gravity waves excited during an inflationary epoch shortly after the Big Bang. PIPER consists of two co-pointed telescopes, one sensitive to the Q Stokes parameter and the other to U. Sky signals will be detected with 5120 transition edge sensor (TES) bolometers distributed in four rectangular close-packed arrays maintained at 150 mK. To maximize the sensitivity of the instrument, both telescopes are mounted within a single open bucket dewar and are maintained at 1.5 K throughout flight, with no ambient-temperature windows between the sky and the detectors. To mitigate the effects of systematic errors, the polarized sky signals will be modulated using a variable-delay polarization modulator. PIPER will observe at frequencies 200, 270, 350, and 600 GHz to separate the CMB from polarized dust emission within the Galaxy. A series of flights alternating between northern and southern hemisphere launch sites will produce nearly full-sky maps in Stokes I, Q, U, and V. I will discuss the current status and potential science returns from the PIPER project.
NASA Astrophysics Data System (ADS)
He, Xiao-Gang; Ma, Bo-Qiang
We show that black holes can be quantized in an intuitive and elegant way with results in agreement with conventional knowledge of black holes by using Bohr's idea of quantizing the motion of an electron inside the atom in quantum mechanics. We find that properties of black holes can also be derived from an ansatz of quantized entropy Δ S = 4π k Δ R/{{-{λ }}}, which was suggested in a previous work to unify the black hole entropy formula and Verlinde's conjecture to explain gravity as an entropic force. Such an Ansatz also explains gravity as an entropic force from quantum effect. This suggests a way to unify gravity with quantum theory. Several interesting and surprising results of black holes are given from which we predict the existence of primordial black holes ranging from Planck scale both in size and energy to big ones in size but with low energy behaviors.
Primordial Compositions of Refractory Inclusions
Grossman, L; Simon, S B; Rai, V K; Thiemens, M H; Hutcheon, I D; Williams, R W; Galy, A; Ding, T; Fedkin, A V; Clayton, R N; Mayeda, T K
2008-02-20
Bulk chemical and oxygen, magnesium and silicon isotopic compositions were measured for each of 17 Types A and B refractory inclusions from CV3 chondrites. After bulk chemical compositions were corrected for non-representative sampling in the laboratory, the Mg and Si isotopic compositions of each inclusion were used to calculate its original chemical composition assuming that the heavy-isotope enrichments of these elements are due to Rayleigh fractionation that accompanied their evaporation from CMAS liquids. The resulting pre-evaporation chemical compositions are consistent with those predicted by equilibrium thermodynamic calculations for high-temperature nebular condensates but only if different inclusions condensed from nebular regions that ranged in total pressure from 10{sup -6} to 10{sup -1} bar, regardless of whether they formed in a system of solar composition or in one enriched in OC dust relative to gas by a factor of ten relative to solar composition. This is similar to the range of total pressures predicted by dynamic models of the solar nebula for regions whose temperatures are in the range of silicate condensation temperatures. Alternatively, if departure from equilibrium condensation and/or non-representative sampling of condensates in the nebula occurred, the inferred range of total pressure could be smaller. Simple kinetic modeling of evaporation successfully reproduces observed chemical compositions of most inclusions from their inferred pre-evaporation compositions, suggesting that closed-system isotopic exchange processes did not have a significant effect on their isotopic compositions. Comparison of pre-evaporation compositions with observed ones indicates that 80% of the enrichment in refractory CaO + Al{sub 2}O{sub 3} relative to more volatile MgO + SiO{sub 2} is due to initial condensation and 20% due to subsequent evaporation for both Type A and Type B inclusions.
Primordial trispectrum from isocurvature fluctuations
Langlois, David; Takahashi, Tomo E-mail: tomot@cc.saga-u.ac.jp
2011-02-01
We study non-Gaussianity generated by adiabatic and isocurvature primordial perturbations. We first obtain, in a very general setting, the non-linear perturbations, up to third order, for an arbitrary number of cosmological fluids, going through one or several decay transitions. We then apply this formalism to the mixed curvaton and inflaton model, allowing for several decay channels. We compute the various contributions to the bispectrum and trispectrum resulting from adiabatic and isocurvature perturbations, which are correlated in general. By investigating some hybrid decay scenario, we show that significant non-Gaussianity of adiabatic and isocurvature types can be generated without conflicting with the present isocurvature constraints from the power spectrum. In particular, we find cases where non-Gaussianity of isocurvature origin can dominate its adiabatic counterpart, both in the bispectrum and in the trispectrum.
Radiative and Kinetic Feedback by Low-Mass Primordial Stars
NASA Astrophysics Data System (ADS)
Whalen, Daniel; Hueckstaedt, Robert M.; McConkie, Thomas O.
2010-03-01
Ionizing UV radiation and supernova (SN) flows amidst clustered minihalos at high redshift regulated the rise of the first stellar populations in the universe. Previous studies have addressed the effects of very massive primordial stars on the collapse of nearby halos into new stars, but the absence of the odd-even nucleosynthetic signature of pair-instability SNe in ancient metal-poor stars suggests that Population III stars may have been less than 100 M sun. We extend our earlier survey of local UV feedback on star formation to 25-80 M sun stars and include kinetic feedback by SNe for 25-40 M sun stars. We find radiative feedback to be relatively uniform over this mass range, primarily because the larger fluxes of more massive stars are offset by their shorter lifetimes. Our models demonstrate that prior to the rise of global UV backgrounds, Lyman-Werner (LW) photons from nearby stars cannot prevent halos from forming new stars. These calculations also reveal that violent dynamical instabilities can erupt in the UV radiation front enveloping a primordial halo, but that they ultimately have no effect on the formation of a star. Finally, our simulations suggest that relic H II regions surrounding partially evaporated halos may expel LW backgrounds at lower redshifts, allowing stars to form that were previously suppressed. We provide fits to radiative and kinetic feedback on star formation for use in both semianalytic models and numerical simulations.
The Solar System primordial lead
NASA Astrophysics Data System (ADS)
Blichert-Toft, Janne; Zanda, Brigitte; Ebel, Denton S.; Albarède, Francis
2010-11-01
Knowledge of the primordial isotope composition of Pb in the Solar System is critical to the understanding of the early evolution of Earth and other planetary bodies. Here we present new Pb isotopic data on troilite (FeS) nodules from a number of different iron meteorites: Canyon Diablo, Mundrabilla, Nantan, Seeläsgen, Toluca (IAB-IIICD), Cape York (IIIA), Mt Edith (IIIB), and Seymchan (pallasite). Lead abundances and isotopic compositions typically vary from one troilite inclusion to another, even within the same meteorite. The most primitive Pb was found in three leach fractions of two exceptionally Pb-rich Nantan troilite nodules. Its 204Pb/ 206Pb is identical to that of Canyon Diablo troilite as measured by Tatsumoto et al. [M. Tatsumoto, R.J. Knight, C.J. Allègre, Time differences in the formation of meteorites as determined from the ratio of lead-207 to lead-206, Science 180(1973) 1279-1283]. However, our measurements of 207Pb/ 206Pb and 208Pb/ 206Pb are significantly higher than theirs, as well as other older literature data obtained by TIMS, while consistent with the recent data of Connelly et al. [J.N. Connelly, M. Bizzarro, K. Thrane, J.A. Baker, The Pb-Pb age of Angrite SAH99555 revisited, Geochim. Cosmochim. Acta 72(2008) 4813-4824], a result we ascribe to instrumental mass fractionation having biased the older data. Our current best estimate of the Solar System primordial Pb is that of Nantan troilite, which has the following isotopic composition: 204Pb/ 206Pb = 0.107459(16), 207Pb/ 206Pb = 1.10759(10), and 208Pb/ 206Pb = 3.17347(28). This is slightly less radiogenic than the intercept of the bundle of isotopic arrays formed in 207Pb/ 206Pb- 204Pb/ 206Pb space by our measurements of Canyon Diablo, Nantan, Seeläsgen, Cape York, and Mundrabilla, as well as literature data, which, in spite of rather large uncertainties, suggests a common primordial Pb component for all of these meteorites. The radiogenic Pb present in most of these irons is dominantly
Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
Jin, Sheng; Ji, Jianghui; Mordasini, Christoph; Van Boekel, Roy; Henning, Thomas; Parmentier, Vivien E-mail: mordasini@mpia.de
2014-11-01
We apply hydrodynamic evaporation models to different synthetic planet populations that were obtained from a planet formation code based on the core-accretion paradigm. We investigated the evolution of the planet populations using several evaporation models, which are distinguished by the driving force of the escape flow (X-ray or EUV), the heating efficiency in energy-limited evaporation regimes, or both. Although the mass distribution of the planet populations is barely affected by evaporation, the radius distribution clearly shows a break at approximately 2 R {sub ⊕}. We find that evaporation can lead to a bimodal distribution of planetary sizes and to an 'evaporation valley' running diagonally downward in the orbital distance—planetary radius plane, separating bare cores from low-mass planets that have kept some primordial H/He. Furthermore, this bimodal distribution is related to the initial characteristics of the planetary populations because low-mass planetary cores can only accrete small primordial H/He envelopes and their envelope masses are proportional to their core masses. We also find that the population-wide effect of evaporation is not sensitive to the heating efficiency of energy-limited description. However, in two extreme cases, namely without evaporation or with a 100% heating efficiency in an evaporation model, the final size distributions show significant differences; these two scenarios can be ruled out from the size distribution of Kepler candidates.
Wilmarth, W.R.
1999-04-15
Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning.
Primordial Cratering Regimes on Planets
NASA Astrophysics Data System (ADS)
Hartmann, W. K.
2004-11-01
Understanding of planetary surface evolution (and possibly biological evolution) is hampered by a longstanding uncertainty over the nature of impact cratering and interplanetary debris in the first 600 My of solar system history. On the one hand, a number of researchers (1-3) treat a cataclysmic spike in cratering 3.9 Gy ago as an observational fact, arguing that little or no cratering occurred from 4.5 to 4.0 Gy ago, and that all multi-ring lunar basins formed 3.85 to 4.0 Gy ago. On the other hand, dynamical theorists have had problems trying to explain the a large impactor spike, as reviewed in (4). Worse yet, meteorite evidence on lunar and asteroidal impact melts (3,5) fail to confirm the strong spike in Apollo-sample impact melts at 3.9 Gy. A semi-quantitative model has been suggested to reconcile the findings (5). References: (1) Tera, F., D.A. Papanastassiou, G. J. Wasserberg 1974. Isotopic evidence for a terminal Lunar cataclysm, Earth Planet. Sci. Lett. 22, 1-21. (2) Stoeffler, D., G. Ryder 2001. "Stratigraphy and Isotope Ages of Lunar Geologic Units: Chronological Standard for the Inner Solar System," in Chronology and Evolution of Mars, Eds. R. Kallenbach, J. Geiss, W. K. Hartmann. Kluwer Academic Publishers, Netherlands, pp. 105-164. (3) Cohen, B. A., T. D. Swindle, D. A. Kring 2000. Support for the Lunar Cataclysm Hypothesis from Lunar Meteorite Impact Melt Ages. Science 290, 1754-1756. (4) Hartmann, W. K., G. Ryder, L. Dones, D. Grinspoon 2000. The Time-Dependent Intense Bombardment of the Primordial Earth/Moon System. In Origin of the Earth and Moon, Eds. R. M. Canup, K. Righter (Tucson: Univ. Arizona Press), pp. 493-512. (5) Hartmann, W. K. 2003. Megaregolith evolution and cratering cataclysm models - Lunar cataclysm as a misconception (28 years later). Meteor. Planet. Sci. 38, 579-593.
Evaporation in space manufacturing
NASA Technical Reports Server (NTRS)
Li, C. H.
1974-01-01
'Normal evaporation' equations for predicting the compositional changes with time and temperature have been developed and correlated with actual experimental data. An evaporative congruent temperature is defined and used to explain, predict, or plan space experiments on anomalous constitutional melting (on cooling) or solidification (on heating). Uneven evaporation causes reactive jetting forces capable of initiating new convection currents, nongravitational accelerations, surface vibrations, or other disturbances. Applications of evaporation to space manufacturing are described concerning evaporative purification, surface cooling, specimen selection, particles splitting, freezing data interpretation, material loss and dimensional control, and surface contamination or compositional changes.
PIPER: Primordial Inflation Polarization Explorer
NASA Astrophysics Data System (ADS)
Lazear, Justin; Ade, P.; Benford, D. J.; Bennett, C. L.; Chuss, D. T.; Dotson, J. L.; Eimer, J.; Fixsen, D. J.; Halpern, M.; Hinderks, J.; Hinshaw, G. F.; Irwin, K.; Jhabvala, C.; Johnson, B.; Kogut, A. J.; Mirel, P.; Moseley, S. H.; Staguhn, J.; Switzer, E.; Tucker, C. E.; Weston, A.; Wollack, E.
2014-01-01
The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne cosmic microwave background (CMB) polarization experiment searching for large-angular scale B-mode polarization to constrain Inflation in the early universe. The Inflationary Big Bang theory predicts that the epoch of inflation will result in a background of gravitational waves. These gravitational waves imprinted their unique B-mode signature on the CMB polarization, two features of which are a peak at ell ~ 80 and a "bump" below ell ~ 10 in the B-mode angular power spectrum. The ell ~ 80 "recombination" peak is the first peak caused by gravitational waves imprinting tensor (B-mode) perturbations onto the CMB spectrum during recombination. Gravitational waves at larger scales have not yet entered the horizon and may not contribute, and at smaller scales have decayed away by other interactions, giving rise to a peak at horizon scale. The ell ~ 10 "reionization" bump is caused by a similar mechanism as the recombination peak, where gravitational waves imprint B-mode perturbations into the spectrum, now at larger horizon scales. PIPER will target the reionization bump while keeping enough angular resolution to measure the recombination peak, with sensitivity down to tensor-to-scalar ratio r = 0.007. A series of flights alternating between north and south will produce nearly full-sky temperature and polarization maps and measure the low-ell spectra. 5120 transition edge sensor (TES) bolometers each with 20 arcmin beamwidth, distributed into 4 rectangular close-packed arrays maintained at 150 mK will provide small-scale resolution and sensitivity. PIPER consists of two co-aligned telescopes, each with a front-end variable-delay polarization modulator rapidly modulating either the Q or U Stokes parameters to provide polarization sensitivity and mitigate systematic errors. To achieve background-limited sensitivity, the entire instrument is enclosed in an open bucket dewar maintained at 1.5 K. PIPER
Primordial Xenon in Allende Sulfides
NASA Astrophysics Data System (ADS)
Lee, J. T.; Manuel, O. K.
1995-09-01
The Allende C3V carbonaceous chondrite incorporated isotopically anomalous components of several medium-heavy elements (Z=36-62) from nucleosynthesis [1]. Isotopically distinct Xe (Z=54) has been found in grains ranging from several _ to a few mm in size. Diamond [2] is the host of Xe that is enriched in isotopes produced by the very rapid p- and r-processes in a supernova explosion [3]. Silicon carbide [4] is the host of Xe that is enriched in the middle isotopes, 128-132Xe, produced by slow neutron capture [3] before a star reaches the supernova stage. The present study was undertaken to identify the isotopic composition of primitive Xe initially trapped in sulfides of the Allende meteorite. Two FeS mineral separates were analyzed by stepwise heating. One sample was first irradiated in a neutron flux to generate a tracer isotope, 131*Xe, by the 130Te(n, gamma beta-)131*Xe reaction. The release pattern of this tracer isotope, 131*Xe, closely paralleled the release of primordial 132Xe up to 950 degrees C, when the sulfide melted and released the bulk of its trapped Xe (Figure 1). The Xe released from both samples at 950 deg C was terrestrial in isotopic composition, except for enrichments from spallogenic and radiogenic components (Figure 2). From the results of this and earlier analyses of Xe in meteoritic FeS [5, 6, 7], we conclude that terrestrial-type Xe was dominant in the central region of the protoplanetary nebula, and it remains a major component in the FeS of diverse meteorites and in the terrestrial planets that are rich in Fe, S [8]. References: [1] Begemann F. (1993) Origin and Evolution of the Elements (N. Prantzos et al., eds.), 518-527, Cambridge Univ. [2] Lewis R. S. and Anders E. (1988) LPS XIX, 679-680. [3] Burbidge et al. (1957) Rev. Modern Phys., 29, 547-650. [4] Tang M. and Anders E. (1988) GCA, 52, 1235-1244. [5] Niemeyer S. (1979) GCA, 43, 843-860. [6] Lewis et al. (1979) GCA, 43, 1743-1752. [7] Hwaung G. and Manuel O. K. (1982) Nature, 299
CMB μ distortion from primordial gravitational waves
Ota, Atsuhisa; Yamaguchi, Masahide; Takahashi, Tomo; Tashiro, Hiroyuki E-mail: tomot@cc.saga-u.ac.jp E-mail: gucci@phys.titech.ac.jp
2014-10-01
We propose a new mechanism of generating the μ distortion in cosmic microwave background (CMB) originated from primordial gravitational waves. Such μ distortion is generated by the damping of the temperature anisotropies through the Thomson scattering, even on scales larger than that of Silk damping. This mechanism is in sharp contrast with that from the primordial curvature (scalar) perturbations, in which the temperature anisotropies mainly decay by Silk damping effects. We estimate the size of the μ distortion from the new mechanism, which can be used to constrain the amplitude of primordial gravitational waves on smaller scales independently from the CMB anisotropies, giving more wide-range constraint on their spectral index by combining the amplitude from the CMB anisotropies.
Primordial nucleosynthesis: A cosmological point of view
Mathews, G. J.; Kusakabe, M.; Cheoun, M.-K.
2014-05-09
Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the test-ing ground upon which all cosmological models must ultimately rest. It is our only probe of the universe during the first few minutes of cosmic expansion and in particular during the important radiation-dominated epoch. These lectures review the basic equations of space-time, cosmology, and big bang nucleosynthesis. We will then review the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measure-ments are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we summarize the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.
Galaxy bias and primordial non-Gaussianity
NASA Astrophysics Data System (ADS)
Assassi, Valentin; Baumann, Daniel; Schmidt, Fabian
2015-12-01
We present a systematic study of galaxy biasing in the presence of primordial non-Gaussianity. For a large class of non-Gaussian initial conditions, we define a general bias expansion and prove that it is closed under renormalization, thereby showing that the basis of operators in the expansion is complete. We then study the effects of primordial non-Gaussianity on the statistics of galaxies. We show that the equivalence principle enforces a relation between the scale-dependent bias in the galaxy power spectrum and that in the dipolar part of the bispectrum. This provides a powerful consistency check to confirm the primordial origin of any observed scale-dependent bias. Finally, we also discuss the imprints of anisotropic non-Gaussianity as motivated by recent studies of higher-spin fields during inflation.
Primordial Germ Cell Specification and Migration
Marlow, Florence
2015-01-01
Primordial germ cells are the progenitor cells that give rise to the gametes. In some animals, the germline is induced by zygotic transcription factors, whereas in others, primordial germ cell specification occurs via inheritance of maternally provided gene products known as germ plasm. Once specified, the primordial germ cells of some animals must acquire motility and migrate to the gonad in order to survive. In all animals examined, perinuclear structures called germ granules form within germ cells. This review focuses on some of the recent studies, conducted by several groups using diverse systems, from invertebrates to vertebrates, which have provided mechanistic insight into the molecular regulation of germ cell specification and migration. PMID:26918157
Models of the Primordial Standard Clock
NASA Astrophysics Data System (ADS)
Chen, Xingang; Namjoo, Mohammad Hossein; Wang, Yi
2015-02-01
Oscillating massive fields in the primordial universe can be used as Standard Clocks. The ticks of these oscillations induce features in the density perturbations, which directly record the time evolution of the scale factor of the primordial universe, thus if detected, provide a direct evidence for the inflation scenario or the alternatives. In this paper, we construct a full inflationary model of primordial Standard Clock and study its predictions on the density perturbations. This model provides a full realization of several key features proposed previously. We compare the theoretical predictions from inflation and alternative scenarios with the Planck 2013 temperature data on Cosmic Microwave Background (CMB), and identify a statistically marginal but interesting candidate. We discuss how future CMB temperature and polarization data, non-Gaussianity analysis and Large Scale Structure data may be used to further test or constrain the Standard Clock signals.
Primordial trispectra and CMB spectral distortions
NASA Astrophysics Data System (ADS)
Bartolo, Nicola; Liguori, Michele; Shiraishi, Maresuke
2016-03-01
We study the TTμ bispectrum, generated by correlations between Cosmic Microwave Background temperature (T) anisotropies and chemical potential (μ) distortions, and we analyze its dependence on primordial local trispectrum parameters gNL and τNL. We cross-check our results by comparing the full bispectrum calculation with the expectations from a general physical argument, based on predicting the shape of μ-T correlations from the couplings between short and long perturbation modes induced by primordial non-Gaussianity. We show that both gNL and τNL-parts of the primordial trispectrum source a non-vanishing TTμ signal, contrary to the μμ auto-correlation function, which is sensitive only to the τNL-component. A simple Fisher matrix-based forecast shows that a futuristic, cosmic-variance dominated experiment could in principle detect gNL ~ 0.4 and τNL ~ 40 using TTμ.
Genetics Home Reference: microcephalic osteodysplastic primordial dwarfism type II
... Genetics Home Health Conditions MOPDII microcephalic osteodysplastic primordial dwarfism type II Enable Javascript to view the expand/ ... Open All Close All Description Microcephalic osteodysplastic primordial dwarfism type II ( MOPDII ) is a condition characterized by ...
Laboratory prototype flash evaporator
NASA Technical Reports Server (NTRS)
Gaddis, J. L.
1972-01-01
A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and on-orbit peak heat loads, and Freon 22 for terrestrial flight phases below 120,000 feet altitude. The design features, fabrication techniques used for the prototype unit, redundancy considerations, and the fluid temperature control arrangement are reported in detail. The results of an extensive test program to determine the evaporator operational characteristics under a wide variety of conditions are presented.
Formation of Primordial Supermassive Stars by Rapid Mass Accretion
NASA Astrophysics Data System (ADS)
Hosokawa, Takashi; Yorke, Harold W.; Inayoshi, Kohei; Omukai, Kazuyuki; Yoshida, Naoki
2013-12-01
Supermassive stars (SMSs) forming via very rapid mass accretion (\\dot{M}_*\\gtrsim 0.1 \\,M_\\odot \\,yr^{-1}) could be precursors of supermassive black holes observed beyond a redshift of about six. Extending our previous work, here we study the evolution of primordial stars growing under such rapid mass accretion until the stellar mass reaches 104 - 5 M ⊙. Our stellar evolution calculations show that a star becomes supermassive while passing through the "supergiant protostar" stage, whereby the star has a very bloated envelope and a contracting inner core. The stellar radius increases monotonically with the stellar mass until ~= 100 AU for M * >~ 104 M ⊙, after which the star begins to slowly contract. Because of the large radius, the effective temperature is always less than 104 K during rapid accretion. The accreting material is thus almost completely transparent to the stellar radiation. Only for M * >~ 105 M ⊙ can stellar UV feedback operate and disturb the mass accretion flow. We also examine the pulsation stability of accreting SMSs, showing that the pulsation-driven mass loss does not prevent stellar mass growth. Observational signatures of bloated SMSs should be detectable with future observational facilities such as the James Webb Space Telescope. Our results predict that an inner core of the accreting SMS should suffer from the general relativistic instability soon after the stellar mass exceeds 105 M ⊙. An extremely massive black hole should form after the collapse of the inner core.
Primordial spectra from sudden turning trajectory
Noumi, Toshifumi; Yamaguchi, Masahide E-mail: gucci@phys.titech.ac.jp
2013-12-01
Effects of heavy fields on primordial spectra of curvature perturbations are discussed in inflationary models with a sudden turning trajectory. When heavy fields are excited after the sudden turn and oscillate around the bottom of the potential, the following two effects are generically induced: deformation of the inflationary background spacetime and conversion interactions between adiabatic and isocurvature perturbations, both of which can affect the primordial density perturbations. In this paper, we calculate primordial spectra in inflationary models with sudden turning potentials taking into account both of the two effects appropriately. We find that there are some non-trivial correlations between the two effects in the power spectrum and, as a consequence, the primordial scalar power spectrum has a peak around the scale exiting the horizon at the turn. Though both effects can induce parametric resonance amplifications, they are shown to be canceled out for the case with the canonical kinetic terms. The peak feature and the scale dependence of bispectra are also discussed.
Dynamical dispersal of primordial asteroid families
NASA Astrophysics Data System (ADS)
Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.; Aljbaae, S.; Huaman, M. E.
2016-03-01
Many asteroid families are identified and well characterized all over the main asteroid belt. Interestingly, however, none of them are older than 4 Gyr. Many mechanisms have been proposed to disperse such old primordial asteroid families that presumably have existed, but only very few have really worked. Here we present a plausible mechanism for dispersing primordial asteroid families that is based on the 5-planet instability model known as jumping Jupiter. Using two different evolutions for the jumping-Jupiter model, we have numerically integrated orbits of eight putative primordial families. Our results show that the most important effect on the asteroid families' eccentricity and inclination dispersal is that of the secular resonances, in some cases associated with the mean motion resonances. As for the semimajor axes spreading we find that the principal effect is that of close encounters with the fifth giant planet whose orbit briefly overlaps with (part of) the main belt. Therefore, the existence of a fifth giant planet with the mass comparable with that of Uranus' or Neptune's could contribute in important ways to dispersal of the primordial asteroid families. To have that effect, the interloper planet should go into and considerably interact with the asteroids during the instability phase.
Primordial magnetic field limits from cosmological data
Kahniashvili, Tina; Tevzadze, Alexander G.; Sethi, Shiv K.; Pandey, Kanhaiya; Ratra, Bharat
2010-10-15
We study limits on a primordial magnetic field arising from cosmological data, including that from big bang nucleosynthesis, cosmic microwave background polarization plane Faraday rotation limits, and large-scale structure formation. We show that the physically relevant quantity is the value of the effective magnetic field, and limits on it are independent of how the magnetic field was generated.
Evaporation, Boiling and Bubbles
ERIC Educational Resources Information Center
Goodwin, Alan
2012-01-01
Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…
Measure Guideline: Evaporative Condensers
German, A; Dakin, B.; Hoeschele, M.
2012-03-01
This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.
Evaporative Cooling Membrane Device
NASA Technical Reports Server (NTRS)
Lomax, Curtis (Inventor); Moskito, John (Inventor)
1999-01-01
An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.
Signatures of black holes at the LHC
NASA Astrophysics Data System (ADS)
Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.
2007-06-01
Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.
Schwarzschild Black Holes can Wear Scalar Wigs
NASA Astrophysics Data System (ADS)
Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-08-01
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations.
Schwarzschild black holes can wear scalar wigs.
Barranco, Juan; Bernal, Argelia; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier
2012-08-24
We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultralight scalar field dark matter around supermassive black holes and axionlike scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic in the sense that fairly arbitrary initial data evolve, at late times, as a combination of those long-lived configurations. PMID:23002734
NASA Technical Reports Server (NTRS)
Dietz, J. B.
1976-01-01
A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.
Primordial power spectra from anisotropic inflation
Dulaney, Timothy R.; Gresham, Moira I.
2010-05-15
We examine cosmological perturbations in a dynamical theory of inflation in which an Abelian gauge field couples directly to the inflaton, breaking conformal invariance. When the coupling between the gauge field and the inflaton takes a specific form, inflation becomes anisotropic and anisotropy can persist throughout inflation, avoiding Wald's no-hair theorem. After discussing scenarios in which anisotropy can persist during inflation, we calculate the dominant effects of a small persistent anisotropy on the primordial gravitational wave and curvature perturbation power spectra using the ''in-in'' formalism of perturbation theory. We find that the primordial power spectra of cosmological perturbations gain significant direction dependence and that the fractional direction dependence of the tensor power spectrum is suppressed in comparison to that of the scalar power spectrum.
The Primordial Inflation Polarization Explorer (PIPER)
NASA Technical Reports Server (NTRS)
Kogut, Alan J.
2012-01-01
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne instrument to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the polarization of the cosmic microwave background. PIPER combines cold (1.5 K) optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. A series of flights alternating between northern and southern hemisphere launch sites will produce maps in Stokes I, Q, U, and V parameters at frequencies 200, 270, 350, and 600 GHz (wavelengths 1500, 1100, 850, and 500 microns) covering 85% of the sky. We describe the PIPER instrument and discuss the current status and expected science returns from the mission.
Primordial cosmic fluctuations for variable gravity
NASA Astrophysics Data System (ADS)
Wetterich, C.
2016-05-01
The observability of primordial cosmic fluctuations does not require a geometric horizon H‑1, which is exceeded temporarily by the wavelength of fluctuations. The primordial information can be protected against later thermal washout even if all relevant wavelengths remain smaller than H‑1. This is demonstrated by formulating the equations governing the cosmic fluctuations in a form that is manifestly invariant under conformal field transformations of the metric. Beyond the field equations this holds for the defining equation for the correlation function, as expressed by the inverse of the second functional derivative of the quantum effective action. An observable almost scale invariant spectrum does not need an expanding geometry. For a variable Planck mass it can even arise in flat Minkowski space.
Primordial nucleosynthesis and Dirac's large numbers hypothesis
NASA Technical Reports Server (NTRS)
Canuto, V.; Hsieh, S.-H.
1980-01-01
Consideration is given to the analysis of Falik (1979) which attempted to show that the cosmological model proposed by Canuto and Hsieh (1978) in which the gravitational constant varies with time contradicts observations of primordial helium. It is shown that the analysis was based on the assumptions that (1) the energy density of radiation in local thermodynamic equilibrium is approximately equal to the fourth power of the equilibrium temperature, where the product of the equilibrium temperature with the scale factor of the Robertson-Walker metric is constant, and (2) the gravitational constant is approximately equal to the inverse of the time even at early cosmological epochs. These assumptions are demonstrated to be invalid in the scale covariant theory of gravitation used to develop the model, thus negating the conclusion that the Canuto and Hsieh model excludes the primordial synthesis of helium.
Radiogenic melting of primordial comet interiors
NASA Astrophysics Data System (ADS)
Wallis, M. K.
1980-04-01
The melting of the core of a primordial comet due to heat released upon the radioactive decay of Al-26 contained within it is discussed. For a spherical, 10-km comet composed of loose snow and mineral grains in the primordial nebula, it is shown that a large fluid dust, droplet and vapor core could develop surrounded by a 1-km thick icy shell with enhanced conductivity and a further 2 km of snow metamorphosing by sublimation, diffusion and condensation into larger ice crystals. As the radioactivity decays, the comet center would gradually refreeze by the deposition of frost and hail on the interior of the ice shell, resulting in a hollow core which could explain the presumed splitting of some disintegrating comets and could have provided a well-protected environment for elementary biological systems.
Primordial Odontogenic Tumor: Report of a Case.
Slater, Lee J; Eftimie, Liviu F; Herford, Alan S
2016-03-01
Primordial odontogenic tumor (POT) was first described in 2014. It typically presents in the posterior mandible of a child or adolescent as a "dentigerous cyst-like" well-circumscribed radiolucency associated with an unerupted molar. POT consists of an ellipsoidal mass of dental papilla-like myxoid connective tissue entirely enveloped in a delicate membrane of ameloblastic epithelium. It shows features of a developing tooth with a huge dental papilla, and because it is devoid of dental hard tissue, it could be regarded a soft tissue odontoma. The lesion histologically mimics early (primordial) stages of tooth development. This report describes a case of POT and POT-like proliferations in an unrelated complex odontoma. PMID:26408843
Suppression of the Primordial Gravitational Waves
NASA Astrophysics Data System (ADS)
Tumurtushaa, Gansukh; Koh, Seoktae; Lee, Bum-Hoon
2016-07-01
We study the primordial gravitational waves induced by space-space condensate inflation model. For modes that cross the comoving horizon during matter dominated era, we calculate the energy spectrum of gravitational waves. The energy spectrum of gravitational waves for our model has significantly suppressed in the low frequency range. The suppression occurs due to the phase transition during the early evolution of the Universe and depends on model parameter.
Primordial helium and the cosmic background radiation
Steigman, Gary
2010-04-01
The products of primordial nucleosynthesis, along with the cosmic microwave background (CMB) photons, are relics from the early evolution of the Universe whose observations probe the standard model of cosmology and provide windows on new physics beyond the standard models of cosmology and of particle physics. According to the standard, hot big bang cosmology, long before any stars have formed a significant fraction ( ∼ 25%) of the baryonic mass in the Universe should be in the form of helium-4 nuclei. Since current observations of {sup 4}He are restricted to low redshift regions where stellar nucleosynthesis has occurred, an observation of high redshift, prestellar, truly primordial {sup 4}He would constitute a fundamental test of the hot, big bang cosmology. At recombination, long after big bang nucleosynthesis (BBN) has ended, the temperature anisotropy spectrum imprinted on the CMB depends on the {sup 4}He abundance through its connection to the electron density and the effect of the electron density on Silk damping. Since the relic abundance of {sup 4}He is relatively insensitive to the universal density of baryons, but is sensitive to a non-standard, early Universe expansion rate, the primordial mass fraction of {sup 4}He, Yp, offers a test of the consistency of the standard models of BBN and the CMB and, provides constraints on non-standard physics. Here, the WMAP seven year data (supplemented by other CMB experiments), which lead to an indirect determination of Yp at high redshift, are compared to the BBN predictions and to the independent, direct observations of {sup 4}He in low redshift, extragalactic HII regions. At present, given the very large uncertainties in the CMB-determined primordial {sup 4}He abundance (as well as for the helium abundances inferred from HII region observations), any differences between the BBN predictions and the CMB observations are small, at a level ∼<1.5σ.
Primordial Inflation Polarization Explorer: Status and Plans
NASA Technical Reports Server (NTRS)
Kogut, Alan
2009-01-01
The Primordial Inflation Polarization Explorer is a balloon-borne instrument to measure the polarization of the cosmic microwave background in order to detect the characteristic signature of gravity waves created during an inflationary epoch in the early universe. PIPER combines cold /I.G K\\ optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. I will discuss the current status and plans for the PIPER instrument.
CAPSULE REPORT: EVAPORATION PROCESS
Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....
Primordial nucleosynthesis revisited via Trojan Horse Results
NASA Astrophysics Data System (ADS)
Pizzone, R. G.; Spartá, R.; Bertulani, C.; Spitaleri, C.; La Cognata, M.; Lamia, L.; Mukhamedzhanov, A.; Tumino, A.
2016-05-01
Big Bang Nucleosynthesis (BBN) requires several nuclear physics inputs and nuclear reaction rates. An up-to-date compilation of direct cross sections of d(d,p)t, d(d,n)3He and 3He(d,p)4He reactions is given, being these ones among the most uncertain bare-nucleus cross sections. An intense experimental effort has been carried on in the last decade to apply the Trojan Horse Method (THM) to study reactions of relevance for the BBN and measure their astrophysical S(E)-factor. The reaction rates and the relative error for the four reactions of interest are then numerically calculated in the temperature ranges of relevance for BBN (0.01
The primordial helium abundance from updated emissivities
Aver, Erik; Olive, Keith A.; Skillman, Evan D.; Porter, R.L. E-mail: olive@umn.edu E-mail: skillman@astro.umn.edu
2013-11-01
Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y{sub p}. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, and Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, and Stasi'nska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y{sub p}. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increased variance (due to additional objects included). From a regression to zero metallicity, we determine Y{sub p} = 0.2465 ± 0.0097, in good agreement with the BBN result, Y{sub p} = 0.2485 ± 0.0002, based on the Planck determination of the baryon density. In the future, a better understanding of why a large fraction of spectra are not well fit by the model will be crucial to achieving an increase in the precision of the primordial helium abundance determination.
Primordial anisotropies in gauged hybrid inflation
NASA Astrophysics Data System (ADS)
Akbar Abolhasani, Ali; Emami, Razieh; Firouzjahi, Hassan
2014-05-01
We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations.
Measure Guideline: Evaporative Condensers
German, A.; Dakin, B.; Hoeschele, M.
2012-03-01
The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.
Vakil, Himanshu B.; Kosky, Philip G.
1982-01-01
In the preparation of the gaseous reactant feed to undergo a chemical reaction requiring the presence of steam, the efficiency of overall power utilization is improved by premixing the gaseous reactant feed with water and then heating to evaporate the water in the presence of the gaseous reactant feed, the heating fluid utilized being at a temperature below the boiling point of water at the pressure in the volume where the evaporation occurs.
Primordial alignment of elliptical galaxies in intermediate redshift clusters
NASA Astrophysics Data System (ADS)
Rong, Yu; Zhang, Shuang-Nan; Liao, Jin-Yuan
2015-10-01
We measure primordial alignments for the red galaxies in the sample of eight massive galaxy clusters in the southern sky from the Cluster Lensing And Supernova survey with Hubble-Very Large Telescope (CLASH-VLT) Large Programme, at a median redshift of 0.375. We find primordial alignment with about 3σ significance in the four dynamically young clusters, but null detection of primordial alignment in the four highly relaxed clusters. The observed primordial alignment is not dominated by any single one of the four dynamically young clusters, and is primarily due to a population of bright galaxies (Mr < -20.5)residing in the region 300-810 kpc from the cluster centres. For the first time, we point out that the combination of radial alignment and halo alignment can cause fake primordial alignment. Finally, we find that the detected alignment for the dynamically young clusters is real rather than fake primordial alignment.
Chiral primordial gravitational waves from a Lifshitz point.
Takahashi, Tomohiro; Soda, Jiro
2009-06-12
We study primordial gravitational waves produced during inflation in quantum gravity at a Lifshitz point proposed by Horava. Assuming power-counting renormalizability, foliation-preserving diffeomorphism invariance, and the condition of detailed balance, we show that primordial gravitational waves are circularly polarized due to parity violation. The chirality of primordial gravitational waves is a quite robust prediction of quantum gravity at a Lifshitz point which can be tested through observations of cosmic microwave background radiation and stochastic gravitational waves. PMID:19658921
Constraints on primordial density perturbations from induced gravitational waves
Assadullahi, Hooshyar; Wands, David
2010-01-15
We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales.
The chemical evolution of self-gravitating primordial disks
NASA Astrophysics Data System (ADS)
Schleicher, Dominik R. G.; Bovino, Stefano; Latif, Muhammad A.; Ferrara, Andrea; Grassi, Tommaso
2016-01-01
Numerical simulations show the formation of self-gravitating primordial disks during the assembly of the first structures in the Universe, in particular, during the formation of Population III and supermassive stars. Their subsequent evolution is expected to be crucial in determining the mass scale of the first cosmological objects, which depends on the temperature of the gas and dominant cooling mechanism. Here, we derive a one-zone framework to explore the chemical evolution of these disks and show that viscous heating leads to the collisional dissociation of an initially molecular gas. The effect is relevant on scales of 10 AU (1000 AU) for a central mass of 10 M⊙ (104 M⊙) at an accretion rate of 10-1 M⊙ yr-1, and provides a substantial heat input to stabilize the disk. If the gas is initially atomic, it remains atomic during the further evolution and the effect of viscous heating is less significant. The additional thermal support is particularly relevant for the formation of very massive objects, such as the progenitors of the first supermassive black holes. The stabilizing impact of viscous heating thus alleviates the need for strong radiation background as a means of keeping the gas atomic.
Formation of primordial supermassive stars by rapid mass accretion
Hosokawa, Takashi; Yoshida, Naoki; Yorke, Harold W.; Inayoshi, Kohei; Omukai, Kazuyuki E-mail: hosokwtk@gmail.com
2013-12-01
Supermassive stars (SMSs) forming via very rapid mass accretion ( M-dot {sub ∗}≳0.1 M{sub ⊙} yr{sup −1}) could be precursors of supermassive black holes observed beyond a redshift of about six. Extending our previous work, here we study the evolution of primordial stars growing under such rapid mass accretion until the stellar mass reaches 10{sup 4–5} M {sub ☉}. Our stellar evolution calculations show that a star becomes supermassive while passing through the 'supergiant protostar' stage, whereby the star has a very bloated envelope and a contracting inner core. The stellar radius increases monotonically with the stellar mass until ≅ 100 AU for M {sub *} ≳ 10{sup 4} M {sub ☉}, after which the star begins to slowly contract. Because of the large radius, the effective temperature is always less than 10{sup 4} K during rapid accretion. The accreting material is thus almost completely transparent to the stellar radiation. Only for M {sub *} ≳ 10{sup 5} M {sub ☉} can stellar UV feedback operate and disturb the mass accretion flow. We also examine the pulsation stability of accreting SMSs, showing that the pulsation-driven mass loss does not prevent stellar mass growth. Observational signatures of bloated SMSs should be detectable with future observational facilities such as the James Webb Space Telescope. Our results predict that an inner core of the accreting SMS should suffer from the general relativistic instability soon after the stellar mass exceeds 10{sup 5} M {sub ☉}. An extremely massive black hole should form after the collapse of the inner core.
Black, Roger L.
1981-01-01
An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.
Optimization of evaporative cooling
NASA Astrophysics Data System (ADS)
Sackett, C. A.; Bradley, C. C.; Hulet, R. G.
1997-05-01
Recent experiments have used forced evaporative cooling to produce Bose-Einstein condensation in dilute gases. The evaporative cooling process can be optimized to provide the maximum phase-space density with a specified number of atoms remaining. We show that this global optimization is approximately achieved by locally optimizing the cooling efficiency at each instant. We discuss how this method can be implemented, and present the results for our 7Li trap. The predicted behavior of the gas is found to agree well with experiment.
Identifying the inflaton with primordial gravitational waves.
Easson, Damien A; Powell, Brian A
2011-05-13
We explore the ability of experimental physics to uncover the underlying structure of the gravitational Lagrangian describing inflation. While the observable degeneracy of the inflationary parameter space is large, future measurements of observables beyond the adiabatic and tensor two-point functions, such as non-gaussianity or isocurvature modes, might reduce this degeneracy. We show that, even in the absence of such observables, the range of possible inflaton potentials can be reduced with a precision measurement of the tensor spectral index, as might be possible with a direct detection of primordial gravitational waves. PMID:21668140
Functions and possible provenance of primordial proteins.
Sommer, Andrei P; Miyake, Norimune; Wickramasinghe, N Chandra; Narlikar, Jayant V; Al-Mufti, Shirwan
2004-01-01
Nanobacteria or living nanovesicles are of great interest to the scientific community because of their dual nature: on the one hand, they appear as primal biosystems originating life; on the other hand, they can cause severe diseases. Their survival as well as their pathogenic potential is apparently linked to a self-synthesized protein-based slime, rich in calcium and phosphate (when available). Here, we provide challenging evidence for the occurrence of nanobacteria in the stratosphere, reflecting a possibly primordial provenance of the slime. An analysis of the slime's biological functions may lead to novel strategies suitable to block adhesion modalities in modern bacterial populations. PMID:15595742
Blue running of the primordial tensor spectrum
Gong, Jinn-Ouk
2014-07-01
We examine the possibility of positive spectral index of the power spectrum of the primordial tensor perturbation produced during inflation in the light of the detection of the B-mode polarization by the BICEP2 collaboration. We find a blue tilt is in general possible when the slow-roll parameter decays rapidly. We present two known examples in which a positive spectral index for the tensor power spectrum can be obtained. We also briefly discuss other consistency tests for further studies on inflationary dynamics.
Relic Density of Neutrinos with Primordial Asymmetries
Pastor, Sergio; Pinto, Teguayco; Raffelt, Georg G.
2009-06-19
We study flavor oscillations in the early Universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the degree of flavor equilibration, but for the first time also kinetic equilibration among neutrinos and with the ambient plasma. Typically, the restrictive big-bang nucleosynthesis bound on the nu{sub e}nu{sub e} asymmetry indeed applies to all flavors as claimed in the previous literature, but fine-tuned initial asymmetries always allow for a large surviving neutrino excess radiation that may show up in precision cosmological data.
Search for primordial symmetry breakings in CMB
NASA Astrophysics Data System (ADS)
Shiraishi, Maresuke
2016-06-01
There are possibilities to violate symmetries (e.g. parity and rotational invariance) in the primordial cosmological fluctuations. Such symmetry breakings can imprint very rich signatures in late-time phenomena, which may be possible to observe. Especially, Cosmic Microwave Background (CMB) will change its face drastically, corresponding to the symmetry-breaking types, since the harmonic-space representation is very sensitive to the statistical, spin and angular dependences of cosmological perturbations. Here, we discuss (1) general responses of CMB to the symmetry breakings, (2) some theoretical models creating interesting CMB signatures, and (3) aspects of the estimation from observational data.
The Primordial Inflation Polarization Explorer (PIPER)
NASA Technical Reports Server (NTRS)
Chuss, David
2010-01-01
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne polarimeter that will measure the polarization of the cosmic microwave background to search for evidence for inflation. PIPER will observe more than half of the sky in four frequency bands from 200 to 600 GHz with a beam size of 21 arcminutes at the lowest frequency. PIPER simultaneously measures all four Stokes parameters using four co-aligned 32 by 40 element planar bolometer arrays. We give an instrument overview and report on the current status of the instrument.
The Primordial Inflation Polarization Explorer (PIPER)
NASA Technical Reports Server (NTRS)
Chuss, David T.
2010-01-01
The Primordial Inflation Polarization Explorer (PIPER) is a ba1loon-borne instrument designed to search for the faint signature of inflation in the polarized component of the cosmic microwave background (CMB). PIPER will measure the CMB polarization at 4 frequencies (l per flight) using a pair of cryogenic telescopes, one for measuring each of Stokes Q and U in the instrument frame. Each telescope receives both linear orthogonal polarizations in two 32 by 40 element planar arrays that utilize Transition-Edge Sensors (TES). The first element in each telescope is a variable-delay polarization modulator (VPM) that fully modulates the Stokes parameter to which the telescope is sensitive.
Relic density of neutrinos with primordial asymmetries.
Pastor, Sergio; Pinto, Teguayco; Raffelt, Georg G
2009-06-19
We study flavor oscillations in the early Universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the degree of flavor equilibration, but for the first time also kinetic equilibration among neutrinos and with the ambient plasma. Typically, the restrictive big-bang nucleosynthesis bound on the nu_{e}nu[over]_{e} asymmetry indeed applies to all flavors as claimed in the previous literature, but fine-tuned initial asymmetries always allow for a large surviving neutrino excess radiation that may show up in precision cosmological data. PMID:19658994
Primordial magnetic fields and nonlinear electrodynamics
Kunze, Kerstin E.
2008-01-15
The creation of large scale magnetic fields is studied in an inflationary universe where electrodynamics is assumed to be nonlinear. After inflation ends electrodynamics becomes linear and thus the description of reheating and the subsequent radiation dominated stage are unaltered. The nonlinear regime of electrodynamics is described by Lagrangians having a power-law dependence on one of the invariants of the electromagnetic field. It is found that there is a range of parameters for which primordial magnetic fields of cosmologically interesting strengths can be created.
Primordial fluctuations in extended Liouville theory
NASA Astrophysics Data System (ADS)
Moore, Wynton E.
2015-03-01
Liouville gravity can be used to precisely model features of 3+1 dimensional cosmology in a simplified 1+1d setting. We study primordial fluctuations in a generally covariant extension of Liouville theory, in the context of single field inflation. The scale invariant spectrum of scalar curvature perturbations is exhibited, and their three-point correlation function is computed in the slow roll approximation. We recover Maldacena's consistency relation for the three-point function, which in this context depends on a global shift symmetry of extended Liouville theory.
Primordial fluctuations in extended Liouville theory
NASA Astrophysics Data System (ADS)
Moore, Wynton E.
Liouville gravity can be used to precisely model features of 3+1 dimensional cosmology in a simplified 1+1d setting. We study primordial fluctuations in a generally covariant extension of Liouville theory, in the context of single field inflation. The scale invariant spectrum of scalar curvature perturbations is exhibited, and their three-point correlation function is computed in the slow roll approximation. We recover Maldacena's consistency relation for the three-point function, which in this context depends on a global shift symmetry of extended Liouville theory.
Isotope mass fractionation during evaporation of Mg2SiO4
NASA Technical Reports Server (NTRS)
Davis, Andrew M.; Clayton, Robert N.; Mayeda, Toshiko K.; Hashimoto, Akihiko
1990-01-01
Synthetic forsterite (Mg2SiO4) was partially evaporated in vacuum for various durations and at different temperatures. The residual charges obtained when molten Mg2SiO4 was evaporated to 12 percent of its initial mass were enriched in heavy isotopes by about 20, 30, and 15 per mil/amu for O, Mg, and Si, respectively, whereas solid forsterite evaporated to a similar residual mass fraction showed negligible fractionations. These results imply that calcium and aluminum-rich refractory inclusions in carbonaceous chondrites must have been at least partially molten in the primordial solar nebula if the observed large mass fractionation effects were caused by evaporation processes in the nebula.
Detecting primordial B-modes after Planck
NASA Astrophysics Data System (ADS)
Creminelli, Paolo; López Nacir, Diana; Simonović, Marko; Trevisan, Gabriele; Zaldarriaga, Matias
2015-11-01
We update the forecasts for the measurement of the tensor-to-scalar ratio r for various ground-based experiments (AdvACT, CLASS, Keck/BICEP3, Simons Array, SPT-3G), balloons (EBEX 10k and Spider) and satellites (CMBPol, COrE and LiteBIRD), taking into account the recent Planck data on polarized dust and using a component separation method. The forecasts do not change significantly with respect to previous estimates when at least three frequencies are available, provided foregrounds can be accurately described by few parameters. We argue that a theoretically motivated goal for future experiments is r~2×10-3, and that this is achievable if the noise is reduced to ~1 μK-arcmin and lensing is reduced to 10% in power. We study the constraints experiments will be able to put on the frequency and l-dependence of the tensor signal as a check of its primordial origin. Futuristic ground-based and balloon experiments can have good constraints on these parameters, even for r~2×10-3. For the same value of r, satellites will marginally be able to detect the presence of the recombination bump, the most distinctive feature of the primordial signal.
Sex Specification and Heterogeneity of Primordial Germ Cells in Mice
Sakashita, Akihiko; Kawabata, Yukiko; Jincho, Yuko; Tajima, Shiun; Kumamoto, Soichiro; Kobayashi, Hisato; Matsui, Yasuhisa; Kono, Tomohiro
2015-01-01
In mice, primordial germ cells migrate into the genital ridges by embryonic day 13.5 (E13.5), where they are then subjected to a sex-specific fate with female and male primordial germ cells undergoing mitotic arrest and meiosis, respectively. However, the sex-specific basis of primordial germ cell differentiation is poorly understood. The aim of this study was to investigate the sex-specific features of mouse primordial germ cells. We performed RNA-sequencing (seq) of E13.5 female and male mouse primordial germ cells using next-generation sequencing. We identified 651 and 428 differentially expressed transcripts (>2-fold, P < 0.05) in female and male primordial germ cells, respectively. Of these, many transcription factors were identified. Gene ontology and network analysis revealed differing functions of the identified female- and male-specific genes that were associated with primordial germ cell acquisition of sex-specific properties required for differentiation into germ cells. Furthermore, DNA methylation and ChIP-seq analysis of histone modifications showed that hypomethylated gene promoter regions were bound with H3K4me3 and H3K27me3. Our global transcriptome data showed that in mice, primordial germ cells are decisively assigned to a sex-specific differentiation program by E13.5, which is necessary for the development of vital germ cells. PMID:26700643
Variable speed of light cosmology, primordial fluctuations and gravitational waves
NASA Astrophysics Data System (ADS)
Moffat, J. W.
2016-03-01
A variable speed of light (VSL) cosmology is described in which the causal mechanism of generating primordial perturbations is achieved by varying the speed of light in a primordial epoch. This yields an alternative to inflation for explaining the formation of the cosmic microwave background (CMB) and the large scale structure (LSS) of the universe. The initial value horizon and flatness problems in cosmology are solved. The model predicts primordial scalar and tensor fluctuation spectral indices n_s=0.96 and n_t=- 0.04, respectively. We make use of the δ {N} formalism to identify signatures of primordial nonlinear fluctuations, and this allows the VSL model to be distinguished from inflationary models. In particular, we find that the parameter f_NL=5 in the variable speed of light cosmology. The value of the parameter g_NL evolves during the primordial era and shows a running behavior.
MOVES2014: Evaporative Emissions Report
Vehicle evaporative emissions are now modeled in EPA’s MOVES according to physical processes, permeation, tank vapor venting, liquid leaks, and refueling emissions. With this update, the following improvements are being incorporated into MOVES evaporative emissions methodology, a...
Convective Evaporation Of Sprayed Liquid
NASA Technical Reports Server (NTRS)
Bellan, Josette; Harstad, Kenneth G.
1987-01-01
Theoretical model developed to analyze behavior of both dense and dilute clusters of evaporating liquid drops in gas flows. Particularly useful in search for methods of controlling evaporation, ignition, and combustion of fuel sprays.
Phantom energy accretion onto black holes in a cyclic universe
Sun Chengyi
2008-09-15
Black holes pose a serious problem in cyclic or oscillating cosmology. It is speculated that, in the cyclic universe with phantom turnarounds, black holes will be torn apart by phantom energy prior to turnaround before they can create any problems. In this paper, using the mechanism of phantom accretion onto black holes, we find that black holes do not disappear before phantom turnaround. But the remanent black holes will not cause any problems due to Hawking evaporation.
Vertical counterflow evaporative cooler
Bourne, Richard C.; Lee, Brian Eric; Callaway, Duncan
2005-01-25
An evaporative heat exchanger having parallel plates that define alternating dry and wet passages. A water reservoir is located below the plates and is connected to a water distribution system. Water from the water distribution system flows through the wet passages and wets the surfaces of the plates that form the wet passages. Air flows through the dry passages, mixes with air below the plates, and flows into the wet passages before exiting through the top of the wet passages.
NASA Astrophysics Data System (ADS)
Stapinski, Tomasz; Leja, E.
1989-03-01
VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.
Bruns, Lester E.
1976-01-01
A falling film evaporator including a vertically oriented pipe heated exteriorly by a steam jacket and interiorly by a finned steam tube, all heating surfaces of the pipe and steam tube being formed of a material wet by water such as stainless steel, and packing within the pipe consisting of Raschig rings formed of a material that is not wet by water such as polyvinylidene fluoride.
NASA Technical Reports Server (NTRS)
Ungar, Eugene K.; Almlie, Jay C.
2010-01-01
A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.
An Update of the Primordial Helium Abundance
NASA Astrophysics Data System (ADS)
Peimbert, Antonio; Peimbert, Manuel; Luridiana, Valentina
2015-08-01
Three of the best determinations of the primordial helium abundance (Yp) are those obtained from low metallicity HII regions by Aver, Olive, Porter, & Skillman (2013); Izotov, Thuan, & Guseva (2014); and Peimbert, Peimbert, & Luridiana (2007). In this poster we update the Yp determination by Peimbert et al. taking into account, among other aspects, recent advances in the determination of the He atomic physical parameters, the temperature structure, the collisional effects of high temperatures on the Balmer lines, as well as the effect of H and He bound-bound absorption.We compare our results with those of Aver et al. and Izotov et al. and point out possible explanations for the differences among the three determinations. We also compare our results with those obtained with the Plank satellite considering recent measurements of the neutron mean life; this comparison has implications on the determination of the number of light neutrino families.
Microcephalic osteodysplastic primordial dwarfism type 1.
Ferrell, Steven; Johnson, Aaron; Pearson, Waylon
2016-01-01
Microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1) is an uncommon cause of microcephaly and intrauterine growth retardation in a newborn. Early identifying features include but are not limited to sloping forehead, micrognathia, sparse hair, including of eyebrows and short limbs. Immediate radiological findings may include partial or complete agenesis of the corpus callosum, interhemispheric cyst and shallow acetabula leading to dislocation. Genetic testing displaying a mutation in RNU4ATAC gene is necessary for definitive diagnosis. Early identification is important as MOPD1 is an autosomal recessive condition and could present in subsequent pregnancies. The purpose of this case is to both identify and describe some common physical findings related to MOPD1. We present a case of MOPD1 in a girl born to non-consanguineous parents that was distinct for subglottic stenosis and laryngeal cleft. PMID:27312855
Primordial inflation and super-cosmology
NASA Astrophysics Data System (ADS)
Olive, K. A.
A complete, locally supersymmetric model for the early universe is reviewed. It begins with primordial inflation just after the Planck time. The (nontrivial) breaking of SU(5) is discussed in detail, with specific emphasis on baryon generation at T about 0(10 to the 7th)-GeV and monopole suppression (no longer accomplished by inflation). Gravitational effects are taken into account through N = 1 supergravity, and play an essential role. What one is left with is a problem-free scenario containing all the benefits of Guth's (1980) original inflation, as well as density perturbations of a desirable magnitude for the formation of galaxies, a large baryon-to-photon ratio, and a possibly observable flux of magnetic monopoles. By inserting only two scales, the Planck scale and the supersymmetry breaking scale, both the weak and GUT scales are produced.
The origin of life from primordial planets
NASA Astrophysics Data System (ADS)
Gibson, Carl H.; Schild, Rudolph E.; Wickramasinghe, N. Chandra
2011-04-01
The origin of life and the origin of the Universe are among the most important problems of science and they might be inextricably linked. Hydro-gravitational-dynamics cosmology predicts hydrogen-helium gas planets in clumps as the dark matter of galaxies, with millions of planets per star. This unexpected prediction is supported by quasar microlensing of a galaxy and a flood of new data from space telescopes. Supernovae from stellar over-accretion of planets produce the chemicals (C, N, O, P, etc.) and abundant liquid-water domains required for first life and the means for wide scattering of life prototypes. Life originated following the plasma-to-gas transition between 2 and 20 Myr after the big bang, while planetary core oceans were between critical and freezing temperatures, and interchanges of material between planets constituted essentially a cosmological primordial soup. Images from optical, radio and infrared space telescopes suggest life on Earth was neither first nor inevitable.
Primordial Germ Cells: Current Knowledge and Perspectives
Nikolic, Aleksandar; Volarevic, Vladislav; Armstrong, Lyle; Lako, Majlinda; Stojkovic, Miodrag
2016-01-01
Infertility is a condition that occurs very frequently and understanding what defines normal fertility is crucial to helping patients. Causes of infertility are numerous and the treatment often does not lead to desired pregnancy especially when there is a lack of functional gametes. In humans, the primordial germ cell (PGC) is the primary undifferentiated stem cell type that will differentiate towards gametes: spermatozoa or oocytes. With the development of stem cell biology and differentiation protocols, PGC can be obtained from pluripotent stem cells providing a new therapeutic possibility to treat infertile couples. Recent studies demonstrated that viable mouse pups could be obtained from in vitro differentiated stem cells suggesting that translation of these results to human is closer. Therefore, the aim of this review is to summarize current knowledge about PGC indicating the perspective of their use in both research and medical application for the treatment of infertility. PMID:26635880
Primordial gravity waves and weak lensing.
Dodelson, Scott; Rozo, Eduardo; Stebbins, Albert
2003-07-11
Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. The shear can be divided into a gradient mode (G or E) and a curl mode (C or B). The latter is produced only by gravity waves, so the observations of a nonzero curl mode could be seen as evidence for inflation. We find that the expected signal from inflation is small, peaking on the largest scales at l(l+1)C(l)/2pi<10(-11) at l=2 and falling rapidly thereafter. Even for an all-sky deep survey, this signal would be below noise at all multipoles. PMID:12906468
The Primordial Inflation Polarization Explorer (PIPER)
NASA Technical Reports Server (NTRS)
Chuss, David T.
2008-01-01
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment designed to search for the polarized imprint of gravitational waves from cosmic inflation. The discovery of such a signal would provide direct evidence for inflation, and its characterization would provide a means to explore energy scales orders of magnitude larger than any conceivable particle accelerator. PIPER will consist of two cryogenic telescopes-one for each of the Q and U Stokes parameters. Each will use a variable-delay polarization modulator (VPM) as its first element. This architecture is designed to minimize both T->B and E->B systematics. The detectors will be four 32x40 arrays of BUG detectors, utilizing transition-edge sensors and time-domain multiplexing. Each flight will observe approximately 25% of the sky at a single frequency. Additional flights will increase the frequency coverage.
Laboratory Simulations: The Primordial Comet Mantle
NASA Technical Reports Server (NTRS)
Johnson, R. E.
1997-01-01
Laboratory data are needed to understand the formation of organics in cometary and precometary materials and for deciding on the fate of the volatiles. Appropriate experiments were described in the talk at Milipitas. Because of its importance for the comet sample return mission, I discuss here the relevance of this data for predicting the thickness, nature, and ability to survive of the cosmic-ray produced primordial comet mantle ('crust'). That part of the mantle which becomes predominantly refractory is approx. 30 gm/sq cm thick. The tensile strength of this outer mantle is such that it might survive the comet's entrance into the inner solar system. In addition, important modifications to the ices occur to depths approx. 300 gm/cu cm. Based on this it is expected that a deep probe is needed to obtain minimally altered material.