Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Modified Gravity and Cosmology

QUANTUM gravitational effects are usually ignored in calculations of the formation and evolution of black holes. The justification for this is that the radius of curvature of space-time outside the event horizon is very large compared to the Planck length (Għ/c3)1/2 ≈ 10−33 cm, the length scale on which quantum fluctuations of the metric are expected to be of order unity. This means that the energy density of particles created by the gravitational field is small compared to the space-time curvature. Even though quantum effects may be small locally, they may still, however, add up to produce a significant effect over the lifetime of the Universe ≈ 1017 s which is very long compared to the Planck time ≈ 10−43 s. The purpose of this letter is to show that this indeed may be the case: it seems that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M/M)K where κ is the surface gravity of the black hole1. As a black hole emits this thermal radiation one would expect it to lose mass. This in turn would increase the surface gravity and so increase the rate of emission. The black hole would therefore have a finite life of the order of 1071 (M/M)−3 s. For a black hole of solar mass this is much longer than the age of the Universe. There might, however, be much smaller black holes which were formed by fluctuations in the early Universe2. Any such black hole of mass less than 1015 g would have evaporated by now. Near the end of its life the rate of emission would be very high and about 1030 erg would be released in the last 0.1 s. This is a fairly small explosion by astronomical standards but it is equivalent to about 1 million 1 Mton hydrogen bombs. It is often said that nothing can escape from a black hole. But in 1974, Stephen Hawking realized that, owing to quantum effects, black holes should emit particles with a thermal distribution of energies — as if the black hole had a temperature inversely proportional to its mass. In addition to putting black-hole thermodynamics on a firmer footing, this discovery led Hawking to postulate 'black hole explosions', as primordial black holes end their lives in an accelerating release of energy.

Black Hole Explosions

Superstring theoryをめぐって(放談室)

These notes are loosely based on lectures given at the CERN Winter School on Supergravity, Strings and Gauge theories, February 2009, and at the IPM String School in Tehran, April 2009. I have focused on a few concrete topics and also on addressing questions that have arisen repeatedly. Background condensed matter physics material is included as motivation and easy reference for the high energy physics community. The discussion of holographic techniques progresses from equilibrium, to transport and to superconductivity.

https://iopscience.iop.org/article/10.1088/0264-9381/26/22/224002/pdf

Lectures on holographic methods for condensed matter physics

We give analytical arguments and demonstrate numerically the existence of black hole solutions of the 4D effective superstring action in the presence of Gauss-Bonnet quadratic curvature terms. The solutions possess nontrivial dilaton hair. The hair, however, is of "secondary type," in the sense that the dilaton charge is expressed in terms of the black hole mass. Our solutions are not covered by the assumptions of existing proofs of the "no-hair" theorem. We also find some alternative solutions with singular metric behavior, but finite energy. The absence of naked singularities in this system is pointed out.

/pdf/dilatonic-black-holes-in-higher-curvature-string-gravity-1b7f0czfry.pdf

Dilatonic black holes in higher curvature string gravity

/pdf/dilatonic-black-holes-in-higher-curvature-string-gravity-ii-24ci2y3031.pdf

Dilatonic black holes in higher curvature string gravity. II. Linear stability

We consider black holes in Einstein-Yang-Mills theory with a negative cosmological constant. The solutions obtained are somewhat different from those for which the cosmological constant is either positive or zero. Firstly, regular black hole solutions exist for continuous intervals of the parameter space, rather than discrete points. Secondly, there are non-trivial solutions in which the gauge field has no nodes. We show that these solutions are linearly stable.

/pdf/existence-of-stable-hairy-black-holes-in-su-2-einstein-yang-50kqbmqwtr.pdf

Existence of stable hairy black holes in su(2) Einstein-Yang-Mills theory with a negative cosmological constant

In this work, we have continued the study of the Hawking radiation on the brane from a higher-dimensional rotating black hole by investigating the emission of fermionic modes. A comprehensive analysis is performed that leads to the particle, power and angular momentum emission rates, and sheds light on their dependence on fundamental parameters of the theory, such as the spacetime dimension and angular momentum of the black hole. In addition, the angular distribution of the emitted modes, in terms of the number of particles and energy, is thoroughly studied. Our results are valid for arbitrary values of the energy of the emitted particles, dimension of spacetime and angular momentum of the black hole, and complement previous results on the emission of brane-localised scalars and gauge bosons.

/pdf/brane-decay-of-a-4-n-dimensional-rotating-black-hole-iii-1h8v98x0hp.pdf

Brane decay of a (4+n)-dimensional rotating black hole. III: spin-1/2 particles

Can a black hole that suffers a superradiant instability evolve towards a ``hairy'' configuration which is stable? We address this question in the context of Einstein-charged scalar field theory. First, we describe a family of static black hole solutions which possess charged scalar-field hair confined within a mirror-like boundary. Next, we derive a set of equations which govern the linear, spherically symmetric perturbations of these hairy solutions. We present numerical evidence which suggests that, unlike the vacuum solutions, the (single-node) hairy solutions are stable under linear perturbations. Thus, it is plausible that stable hairy black holes represent the end point of the superradiant instability of electrically charged Reissner-Nordstr\"om black holes in a cavity; we outline ways to explore this hypothesis.

Elizabeth Winstanley

Papers

Dilatonic black holes in higher curvature string gravity

Dilatonic black holes in higher curvature string gravity. II. Linear stability

Existence of stable hairy black holes in su(2) Einstein-Yang-Mills theory with a negative cosmological constant

Brane decay of a (4+n)-dimensional rotating black hole. III: spin-1/2 particles

Stability of black holes in Einstein-charged scalar field theory in a cavity