The Tully – Fisher Relation is NOT Evidence of Modified Gravity

by Tommy on 3/01/2017

Maybe finally we can get past this little diversion in astrophysics.

https://arxiv.org/abs/1612.08857

Dark Matter Strikes Back, Paolo Salucci (28 December 2016)

Mc Gaugh et al. (2016) have found, by investigating a large sample of Spirals, a tight non linear relationship between the total radial acceleration, connected with the Dark Matter phenomenon, and its component which comes from the distribution of baryonic matter, as the stellar and HI disks. The strong link between these two quantities is considered by them and by other researchers, as challenging the scenario featuring the presence of DM halos in galaxies. Or, at least, to indicate the peculiar nature of the underlying dark matter particles. We have explored this issue by investigating a larger number of galaxies by means of several techniques of analysis. Our results support and even increase, both qualitatively and quantitatively, the validity of McGaugh et al. (2016) ‘s relationship. However, we prove that such relationship exists also in the scenario featuring dark matter halos + ordinary baryonic matter and that it arises by the fact the DM is less concentrated than the luminous matter and it is progressively more abundant in lower luminosity objects. These properties are due to well known astrophysical effects: the implications of this relationship for the properties of dark matter halos are nothing of new or of unexpected. The relationship, definitively, is not a portal to go beyond the standard picture of ΛCDM galaxy formation.

http://lifeform.net/archimedes/Cosmic_Axions.pdf

Gravitational Axions as Dark Matter

The ‘tip of the iceberg’.

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Heavyish Gravitational Peccei Quinn Axions as Dark Matter

by Tommy on 2/01/2017

http://lifeform.net/archimedes/Cosmic_Axions.pdf

Gravitational Axions as Dark Matter

I had to drop all of the quantum cosmology and gravity onto the cutting room floor, since it is premature, not specific or germane to the discussion (the microwave detection of axions) and it was also very poorly written due to the holidays. I will get back to it later in the inevitable sequel.

Dark Matter Vixens from Venus.

Update: After finishing up editing my essay I ran across this little jewel.

https://arxiv.org/abs/1612.08933

Alternative dark matter candidates: Axions, Andreas Ringwald, Dontribution to the Proceedings of the Neutrino Oscillation Workshop, 4 – 11 September, 2016, Otranto, Lecce, Italy, DESY 16-236 (28 December 2016)

The axion is arguably one of the best motivated candidates for dark matter. For a decay constant greater than about 109 GeV, axions are dominantly produced non-thermally in the early universe and hence are “cold”, their velocity dispersion being small enough to fit to large scale structure. Moreover, such a large decay constant ensures the stability at cosmological time scales and its behaviour as a collisionless fluid at cosmological length scales. Here, we review the state of the art of axion dark matter predictions and of experimental efforts to search for axion dark matter in laboratory experiments.

I wrote my essay because I want more stuff like this essay.

So I added this and now it’s done!

Update: http://lifeform.net/archimedes/Quantum_Cosmology.pdf

Gravitatioal Axions in Quantum Gravity and Cosmology

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Pairing Forces in Quantum Dimer Bound States Studied

by Tommy on 29/12/2016

This result has helped me immensely, and it actually got some press already.

https://arxiv.org/abs/1612.08004

Effective forces between quantum bound states, Alexander Rokash, Evgeny Epelbaum, Hermann Krebs and Dean Lee (23 December 2016)

Recent ab initio lattice studies have found that the interactions between alpha particles (4He nuclei) are quite sensitive to the details of the nucleon-nucleon force. In order to understand the underlying physics, we study a simple model involving two-component fermions in one spatial dimension. We probe the interaction between two bound dimers for several different particle-particle interactions. We measure an effective potential between the dimers using external point potentials which act as numerical tweezers. We find that the strength and range of the local or nearly local part of the particle-particle interactions play a large role in shaping the interactions between the dimers and can even determine the overall sign of the effective potential.

See also: https://arxiv.org/abs/1602.04539

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.132501

Nuclear binding near a quantum phase transition, Serdar Elhatisari, Ning Li, Alexander Rokash, Jose Manuel Alarcón, Dechuan Du, Nico Klein, Bing-nan Lu, Ulf-G. Meißner, Evgeny Epelbaum, Hermann Krebs, Timo A. Lähde, Dean Lee and Gautam Rupak, Phys. Rev. Lett., 117, 132501 (19 September 2016), doi:10.1103/PhysRevLett.117.132501

How do protons and neutrons bind to form nuclei? This is the central question of ab initio nuclear structure theory. While the answer may seem as simple as the fact that nuclear forces are attractive, the full story is more complex and interesting. In this work we present numerical evidence from ab initio lattice simulations showing that nature is near a quantum phase transition, a zero-temperature transition driven by quantum fluctuations. Using lattice effective field theory, we perform Monte Carlo simulations for systems with up to twenty nucleons. For even and equal numbers of protons and neutrons, we discover a first-order transition at zero temperature from a Bose-condensed gas of alpha particles (4He nuclei) to a nuclear liquid. Whether one has an alpha-particle gas or nuclear liquid is determined by the strength of the alpha-alpha interactions, and we show that the alpha-alpha interactions depend on the strength and locality of the nucleon-nucleon interactions. This insight should be useful in improving calculations of nuclear structure and important astrophysical reactions involving alpha capture on nuclei. Our findings also provide a tool to probe the structure of alpha cluster states such as the Hoyle state responsible for the production of carbon in red giant stars and point to a connection between nuclear states and the universal physics of bosons at large scattering length.

http://physicsworld.com/cws/article/news/2016/sep/21/some-nuclei-exist-close-to-a-quantum-phase-transition

https://physics.aps.org/articles/v9/106

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Semi Definitive Sedimentary Nanodiamond Analysis Published

by Tommy on 24/12/2016

This is probably as good as it’s going to get for a while now.

http://onlinelibrary.wiley.com/doi/10.1002/jqs.2892/full

Comprehensive analysis of nanodiamond evidence relating to the Younger Dryas Impact Hypothesis, Tyrone L. Daulton, Sachiko Amari, Andrew C. Scott, Mark Hardiman, Nicholas Pinter and R. Scott Anderson, Journal of Quaternary Science (19 December 2016), DOI:10.1002/jqs.2892

During the end of the last glacial period in the Northern Hemisphere near 12.9k cal a BP, deglacial warming of the Bølling–Ållerod interstadial ceased abruptly and the climate returned to glacial conditions for an interval of about 1300 years known as the Younger Dryas stadial. The Younger Dryas Impact Hypothesis proposes that the onset of the Younger Dryas climate reversal, Pleistocene megafaunal extinctions and disappearance of the Clovis paleoindian lithic technology were coeval and caused by continent-wide catastrophic effects of impact/bolide events in North America. While there are no known impact structures dated to the Younger Dryas onset, physical evidence of the impact/bolide events is argued to be present in sediments spanning several continents at stratigraphic levels inferred to date to the Bølling-Ållerod/Younger Dryas boundary (YDB). Reports of nanometer to submicron-sized diamonds in YDB sediments, in particular the rare 2H hexagonal polytype of diamond, lonsdaleite, have been presented as strong evidence for shock processing of crustal materials. We review the available data on diamonds in sediments and provide new data. We find no evidence for lonsdaleite in YDB sediments and find no evidence of a spike in nanodiamond concentration at the YDB layer to support the impact hypothesis.

This is one failed hypothesis that has driven nanodiamond analysis forward remarkably.

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Dark Matter Axion Detection By Condensed Matter Excitation

by Tommy on 24/12/2016

I think it’s safe to say now that the race to detect the axion has finally and officially begun.

https://arxiv.org/abs/1612.05406

Stimulated Emission of Dark Matter Axion from Condensed Matter Excitations, Naoto Yokoi and Eiji Saitoh (16 December 2016)

We discuss a possible principle for detecting dark matter axions in galactic halos. If axions constitute a condensate in the Milky Way, stimulated emissions of the axions from a type of excitation in condensed matter can be detectable. We provide general mechanism for the dark matter emission, and, as a concrete example, an emission of dark matter axions from magnetic vortex strings in a type II superconductor are investigated along with possible experimental signatures.

Here is the big takeaway from this idea.

There is another interesting problem: The excitation of type C, such as an analogue of the axion in a topological magnetic insulator, has the same effective coupling as the axion coupling. Thus the mixing between the dark matter axions and condensed matter axions can occur in principle. Physical consequences from such a mixing will be discussed in a future work.

That should be a whole lotta fun.

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Enlightening My Cosmic Dark Matter Universe – In a Nutshell

by Tommy on 24/12/2016

This was a whole lotta fun. Mandatory reading for everyone.

https://arxiv.org/abs/1612.06504

Enlightening the dark universe, Abhik Kumar Sanyal, Lecture given on “One day seminar on Einstein and his contributions in Physics and Cosmology to celebrate 100 years of General Theory of Relativity” organized by the Calcutta Institute of Theoretical Physics in collaboration with Department of Mathematics, St. Xavier’s College, Kolkata, on 28th. March, 2015, Indian Journal of Theoretical Physics, Vol 62, Nos. 3,4, 2014. (20 December 2016)

Lot of avenues, the black hole, the wormhole, the dark matter, the dark energy etc. have been opened since the advent of General Theory of Relativity in 1915. Cosmology, the physics of creation and evolution of the universe, which was once thought to be beyond human perseverance, has now become a rich science of highest importance. However, the theory of gravitation, the oldest known interaction, is still not well understood. In the process of unveiling the evolutionary history of the universe, we shall explore some facts that suggest General Theory of Relativity is not the complete theory of gravitation.

Finally all of the threads of the gravitational unknowns have been organized into a single paper.

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Axion Induced Baryogenesis and Baryon Asymmetry Proposed

by Tommy on 20/12/2016

Here is one that is dear to my heart. It’s a start, I guess.

At least some of this is not being taken seriously, though.

https://arxiv.org/abs/1612.04824

Geometric Baryogenesis from Shift Symmetry, Andrea De Simone, Takeshi Kobayashi and Stefano Liberati, SISSA 64/2016/FISI (14 December 2016)

We present a new scenario for generating the baryon asymmetry of the universe that is induced by a Nambu-Goldstone (NG) boson. The shift symmetry naturally controls the operators in the theory, while allowing the NG boson to couple to the spacetime geometry. The cosmological background thus sources a coherent motion of the NG boson, which leads to baryogenesis. Good candidates of the baryon-generating NG boson are the QCD axion and axion-like fields. In these cases the axion induces baryogenesis in the early universe, and can also serve as dark matter in the late universe.

Some very prestigious popular science journalists assured me that the axion doesn’t exist.

Some crackpots and cranks agreed, and so that’s the end of that.

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On the Electrodynamics of Chiral Matter

by Tommy on 20/12/2016

And finally, I leave you with this.

https://arxiv.org/abs/1612.06364

On electrodynamics of chiral matter, Zebin Qiu, Gaoqing Cao and Xu-Guang Huang (9 December 2016)

Many-body systems with chiral fermions can exhibit novel transport phenomena that violate parity and time reversal symmetries, such as the chiral magnetic effect, the anomalous Hall effect, and the anomalous generation of charge. Based on the Maxwell-Chern-Simons electrodynamics, we examine some electromagnetic and optical properties of such systems including the electrostatics, the magnetostatics, the propagation of electromagnetic waves, the novel optical effects, etc.

Regurgitated nearly verbatim, since I’m in a hurry and it’s breakthroughy and reviewyish.

So Happy Chirstmas! Remember, Satan is your friend. Santa, your enemy.

And semi-annual regional hemispherical cooling just … is.

Some astronomers assured me it will pass.

Only to arrive again next year.

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3D Quantum Phases of Majorana and Weyl Fermions Analyzed

by Tommy on 20/12/2016

I’ve been trying to come to grips with these exotic fermionic phases of matter for a while now.

https://arxiv.org/abs/1612.05648

Quantum phases of disordered three-dimensional Majorana-Weyl fermions, Justin H. Wilson, J. H. Pixley, Pallab Goswami and S. Das Sarma (16 December 2016)

The gapless Bogoliubov-de Gennes (BdG) quasiparticles of a clean three dimensional spinless px+ipy superconductor provide an intriguing example of a thermal Hall semimetal (ThSM) phase of Majorana-Weyl fermions in class D of the Altland-Zirnbauer symmetry classification; such a phase can support a large anomalous thermal Hall conductivity and protected surface Majorana-Fermi arcs at zero energy. We study the effect of quenched disorder on such a topological phase with both numerical and analytical methods. Using the kernel polynomial method, we compute the average and typical density of states for the BdG quasiparticles; based on this, we construct the disordered phase diagram. We show for infinitesimal disorder, the ThSM is converted into a diffusive thermal Hall metal (ThDM) due to rare statistical fluctuations. Consequently, the phase diagram of the disordered model only consists of ThDM and thermal insulating phases. Nonetheless, there is a cross-over at finite energies from a ThSM regime to a ThDM regime, and we establish the scaling properties of the avoided quantum critical point which marks this cross-over. Additionally, we show the existence of two types of thermal insulators: (i) a trivial thermal band insulator (ThBI) [or BEC phase] supporting only exponentially localized Lifshitz states (at low energy), and (ii) a thermal Anderson insulator (AI) at large disorder strengths. We determine the nature of the two distinct localization transitions between these two types of insulators and ThDM.We also discuss the experimental relevance of our results for three dimensional, time reversal symmetry breaking, triplet superconducting states.

Every little bit helps. I wish I had more time for this kind of thing, though.

A ‘readers’ stipend would be nice.

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Our Condensed Universe is in Balanced Thermal Equilibrium

by Tommy on 20/12/2016

As I predicted. I missed this on the ArXiv but caught it on Scholar.

https://arxiv.org/abs/1612.04199

Thermal Gravitational Radiation and Condensed Universe, Ti-Pei Li and Mei Wu (7 December 2016)

The perfect Planck spectrum of the observed cosmic microwave background radiation indicates that our universe must be in thermal equilibrium. The dark sector of the universe should also be in the same equilibrium state with dark matter and dark energy coupled to each other and emits gravitational phonon blackbody radiation which is the main component of the cosmic background radiation. In the radiation-dominated era such gravitational radiation should be the majority species of the cosmic medium. Instead of the ideal fluid assumed by the standard cosmological model LCDM, the universe has to be taken as a thermodynamic system consisting of gravitationally connected dark energy and matter. Besides particle dynamics, statistical thermodynamics is also necessary for understanding the cosmological constitution and evolution history. As an alternative to LCDM we constructed a dark-energy-matter-coupled (DEMC) cosmological model. Based on the relativistic mass-energy relation, conservation law of energy, Lagrange’s equation with variable potential function, mean-field theory of continuous phase transition, and the symmetry principle of the kinetic coefficients, we deduced dynamic equations of the expansion of a DEMC universe with three parameters. These equations reproduce the observed history of the rate of expansion of our universe.

I agree with them on this, but I haven’t totally worked through their math yet.

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Collective Excitation of Strongly Coupled Quantum Fluids

by Tommy on 20/12/2016

This is a real winner for me as well.

https://arxiv.org/abs/1612.05500

Higher derivative corrections to incoherent metallic transport in holography, Matteo Baggioli, Blaise Goutéraux, Elias Kiritsis and Wei-Jia Li, CCTP-2016-20, CCQCN-2016-179, NORDITA-2016-129, SU-ITP-1621 (16 December 2016)

Transport in strongly-disordered, metallic systems is governed by diffusive processes. Based on quantum mechanics, it has been conjectured that these diffusivities obey a lower bound D/v2 ≳ ℏ/kBT, the saturation of which provides a mechanism for the T-linear resistivity of bad metals. This bound features a characteristic velocity v, which was later argued to be the butterfly velocity vB, based on holographic models of transport. This establishes a link between incoherent metallic transport, quantum chaos and Planckian timescales. Here we study higher derivative corrections to an effective holographic action of homogeneous disorder. The higher derivative terms involve only the charge and translation symmetry breaking sector. We show that they have a strong impact on the bound on charge diffusion Dc/v2B ≳ ℏ/kBT, by potentially making the coefficient of its right-hand side arbitrarily small. On the other hand, the bound on energy diffusion is not affected.

This is cosmological model building at its best, applicable to a wide variety of other fields.

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High Density of Grain Boundaries for Extremely High ZT Efficiency

by Tommy on 20/12/2016

This is promising. And interesting.

https://arxiv.org/abs/1612.05344

New record of high ZT found in hybrid transition-metal-dichalcogenides, Yulou Ouyang, Yuee Xie, Zhongwei Zhang, Qing Peng and Yuanping Chen, Journal of Applied Physics 120, 2016 (16 December 2016)

The search for thermoelectrics with higher figures of merit (ZT) will never stop due to the demand of heat harvesting. Single layer transition metal dichalcogenides (TMD), namely MX2 (where M is a transition metal and X is a chalcogen) that have electronic band gaps are among the new materials that have been the focus of such research. Here, we investigate the thermoelectric transport properties of hybrid armchair-edged TMDs nanoribbons, by using the nonequilibrium Green’s function technique combined with the first principles and molecular dynamics methods. We find a ZT as high as 7.4 in hybrid MoS2/MoSe2 nanoribbons at 800K, creating a new record for ZT. Moreover, the hybrid interfaces by substituting X atoms are more efficient than those by substituting M atoms to tune the ZT. The origin of such a high ZT of hybrid nanoribbons is the high density of the grain boundaries: the hybrid interfaces decrease thermal conductance drastically without a large penalty to electronic conductance.

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My Special and General Theory of the Cosmic QCD Axions

by Tommy on 17/12/2016

Gravitational Axions as Dark Matter

http://lifeform.net/archimedes/Cosmic_Axions.pdf

This has been a year and a couple of months coming. As usual the alert and attentive get to observe the development of the essay in real time. IT’S NOT DONE YET!!! This is just how I go about publishing crackpot science. I just can’t take anymore Verlinde and Wolchover, and Pavel is driving me nuts. So this is your big chance if you missed me writing all of those other idiotic crackpot essays in real time. It’s now live, and on the internet. I discovered the freakin axion.

Dark matter. Get it? The bosonic stuff of crackpots and crank magnets.

The quantum gravitational field theory will have to come later.

I was told when I have something to say I should say it.

I already said it. Now I’m writing it up.

© 2016 Thomas Lee Elifritz

Officially. For Publication.

Abstract

A hypothesis is developed for cosmic QCD axions, as gravitationally and gravitoelectromagnetically active topological spacetime remnants, derived from inflational scale cosmogenesis events and existing as a quasiparticle excitation spectrum of a ground state bosonic superfluid, interacting directly with the baryons. The guiding principle is axion Higgs electrodynamics in condensed matter physics systems, and the hypothetical axion behavior is justified through both observational and experimental methods.

Special Theory of Cosmic Axions
Gravitational Axions as Dark Matter

General Theory of Cosmic QCD Axions
Goldstone Bosons in Quantum Gravity Gauge Field Theory

Supersymmetry is Dead

Peccei Quinn Axions Exist

QCD Axion Constant is Large

Axion Mass ~ CMB Temperature

Axions in Thermal Equilibrium with CMB

Axion Superfluid Ground State ≤ Superfluid Tc 4He

Axions Interact Gravitoelectromagnetically

Axions as Inflation Scale Remnants

Axions as Topological Remnants

Axions Interact Gravitationally

Quantum Cosmogenesis

Spacetime Pseudogap

Axion Excitation

Update 1: Gravitational Axions in Quantum Gravity and Cosmology

http://lifeform.net/archimedes/Quantum_Cosmology.pdf

Update 2: © 2017 Thomas Lee Elifritz

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Dark Matter Interactions in Spiral Dwarf Galaxies Analyzed

by Tommy on 15/12/2016

I win. Again. I suppose I had better get going on my gravitational axion essay now.

https://arxiv.org/abs/1609.06903

http://mnras.oxfordjournals.org/content/early/2016/11/29/mnras.stw3055

The universal rotation curve of dwarf disk galaxies, E.V. Karukes and P. Salucci, Monthly Notices of the Royal Astronomical Society, MNRAS, 464, 3, January 21, 2017 (29 November 2016), DOI:10.1093/mnras/stw3055

We use the concept of the spiral rotation curves universality (see Persic et al. 1996) to investigate the luminous and dark matter properties of the dwarf disk galaxies in the local volume (size ∼11 Mpc). Our sample includes 36 objects with rotation curves carefully selected from the literature. We find that, despite the large variations of our sample in luminosities (∼ 2 of dex), the rotation curves in specifically normalized units, look all alike and lead to the lower-mass version of the universal rotation curve of spiral galaxies found in Persic et al. (1996). We mass model the double normalized universal rotation curve V(R/Ropt)/Vopt of dwarf disk galaxies: the results show that these systems are totally dominated by dark matter whose density shows a core size between 2 and 3 stellar disk scale lengths. Similar to galaxies of different Hubble types and luminosities, the core radius r0 and the central density ρ0 of the dark matter halo of these objects are related by ρ0r0 ∼ 100 Mpc−2. The structural properties of the dark and luminous matter emerge very well correlated. In addition, to describe these relations, we need to introduce a new parameter, measuring the compactness of light distribution of a (dwarf) disk galaxy. These structural properties also indicate that there is no evidence of abrupt decline at the faint end of the baryonic to halo mass relation. Finally, we find that the distributions of the stellar disk and its dark matter halo are closely related.

‘The tip of the iceberg’. Welcome to my post-big-bang world of condensed matter physics.

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Engine Clustering Comes to Tiny Rockets and Tiny Nations

by Tommy on 14/12/2016

New Zealand Gits Er Done.

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Lonsdaleite Produced By Static Low Temperature Shear Strain

by Tommy on 13/12/2016

Lonsdaleite finally establishes itself as being real.

http://www.nature.com/articles/srep37232

Nanocrystalline hexagonal diamond formed from glassy carbon, Thomas. B. Shiell, Dougal G. McCulloch, Jodie E. Bradby, Bianca Haberl, Reinhard Boehler and David. R. McKenzie, Nature, Scientific Reports 6, 37232 (29 November 2016), doi:10.1038/srep37232

Carbon exhibits a large number of allotropes and its phase behaviour is still subject to significant uncertainty and intensive research. The hexagonal form of diamond, also known as lonsdaleite, was discovered in the Canyon Diablo meteorite where its formation was attributed to the extreme conditions experienced during the impact. However, it has recently been claimed that lonsdaleite does not exist as a well-defined material but is instead defective cubic diamond formed under high pressure and high temperature conditions. Here we report the synthesis of almost pure lonsdaleite in a diamond anvil cell at 100 GPa and 400 °C. The nanocrystalline material was recovered at ambient and analysed using diffraction and high resolution electron microscopy. We propose that the transformation is the result of intense radial plastic flow under compression in the diamond anvil cell, which lowers the energy barrier by “locking in” favourable stackings of graphene sheets. This strain induced transformation of the graphitic planes of the precursor to hexagonal diamond is supported by first principles calculations of transformation pathways and explains why the new phase is found in an annular region. Our findings establish that high purity lonsdaleite is readily formed under strain and hence does not require meteoritic impacts.

And it no longer requires high temperatures, shock compression or meteorite impacts to form or manufacture. That’s a whole lotta wrenches is somebody’s gear. You know that’s gonna hurt.

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Monday Night (the Tuesday Release) on the ArXiv.org

by Tommy on 13/12/2016

At last count there are at least seven or more incredible breakthroughs in the Arxiv tonight.

So I guess it’s game over for the big bang.

Welcome to the post-big-bang era.

It’s quantum cosmogenesis.

You heard it here first.

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The PhD Thesis of Marija Kekić of the Universitat De Valencia

by Tommy on 13/12/2016

Here is yet another wonderful new PhD thesis for you to read.

http://roderic.uv.es/handle/10550/56301

http://roderic.uv.es/bitstream/handle/10550/56301/Tesis.pdf?sequence=1&isAllowed=y

Phenomenology of low-scale Seesaw Models, Marija Kekić, PhD Thesis, Universitat de Valencia, Pilar Hernández Gamazo, Director (9 November 2016)

All the observed particles are well accommodated in the Standard Model, together with the basic forces. However, there are both experimental and theoretical hints that the Standard Model can not be a complete theory and that New Physics is needed. Some of the theoretical problems are: i) The flavor-puzzle, i.e., why are there three copies of particles differing only by their mass. Most of the free parameters in the Standard Model are linked to this puzzle. They have been measured, but their values do not follow any clear pattern and their origin remains elusive. ii) The strong CP problem, that is, why the CP symmetry is conserved in the strong interactions in the Standard Model, which is not ensured by any gauge symmetry. iii) How to combine quantum mechanics with general relativity, since the attempts to do this lead to non-renormalizable theories. Furthermore, gravity …

I can’t wait until I have the time to read it carefully and understand it.

The standard model in a nutshell seems particularly promising.

I have my very own theory of the cosmic nutshell.

Built upon the consensus nutshell.

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The Eric Verlinde Emergent Gravity Wild Goose Chase Begins

by Tommy on 13/12/2016

I wonder how much money they are going to waste on this hunt for WIMPs and MACHOs.

http://mnras.oxfordjournals.org/content/early/2016/12/09/mnras.stw3192

First test of Verlinde’s theory of Emergent Gravity using Weak Gravitational Lensing measurements, Margot M. Brouwer, et al., MNRAS (11 December 2016), doi:10.1093/mnras/stw3192

Verlinde (2016) proposed that the observed excess gravity in galaxies and clusters is the consequence of Emergent Gravity (EG). In this theory the standard gravitational laws are modified on galactic and larger scales due to the displacement of dark energy by baryonic matter. EG gives an estimate of the excess gravity (described as an apparent dark matter density) in terms of the baryonic mass distribution and the Hubble parameter. In this work we present the first test of EG using weak gravitational lensing, within the regime of validity of the current model. Although there is no direct description of lensing and cosmology in EG yet, we can make a reasonable estimate of the expected lensing signal of low redshift galaxies by assuming a background ΛCDM cosmology. We measure the (apparent) average surface mass density profiles of 33,613 isolated central galaxies, and compare them to those predicted by EG based on the galaxies’ baryonic masses. To this end we employ the ∼180 deg2 overlap of the Kilo-Degree Survey (KiDS) with the spectroscopic Galaxy And Mass Assembly (GAMA) survey. We find that the prediction from EG, despite requiring no free parameters, is in good agreement with the observed galaxy-galaxy lensing profiles in four different stellar mass bins. Although this performance is remarkable, this study is only a first step. Further advancements on both the theoretical framework and observational tests of EG are needed before it can be considered a fully developed and solidly tested theory.

This is gonna be so much fun. I can’t wait to be totally wrong again.

Being totally wrong can be so right, if done properly.

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Quantum Arithmetic Disproves Cosmic Naturalness Paradigm

by Tommy on 12/12/2016

Hat tip to Sabine Hossenfelder for this. She is going to destroy them in Munich.

I hope the brawl doesn’t fall out into the Munich streets and only ends up in a Bavarian beer hall.

http://www.cas.uni-muenchen.de/veranstaltungen/tagungen/ws_eva_hartmann/index.html

Reasoning in Physics

International Workshop under the direction of Ben Eva, Ph.D., and Prof. Dr. Stephan Hartmann (CAS Senior Researcher in Residence)

Program and Abstracts Download

Reasoning in Physics – International Workshop at the Center for Advanced Studies, LMU Munich

Modern Physics provides an extremely rich testing ground for philosophical theories of scientific reasoning. In recent times, we have seen the emergence of many new forms of theory confirmation (analogue simulation, the no-alternatives argument, anthropic reasoning, …), necessitated by the empirical inaccessibility of some of the most prominent theories of modern physics and cosmology (string theory, cosmic inflation, …). This workshop will bring together researchers working on the epistemological problems posed by contemporary physical theory, in order to better understand some of these new patterns of physical reasoning and their relationship to traditional theories of scientific reasoning and argumentation in general (e.g. Bayesianism). Another key theme of the workshop will be to explore the ability of traditional Bayesian confirmation theory to account for the wide range of argumentative patterns used by physicists. Relevant issues include, for example, the role and epistemological status of toy models in physics, the ability of Bayesianism to distinguish between neutral and disconfirming evidence, the possibility of providing a Bayesian account of anthropic probabilities, and the question of how strongly a theory can be confirmed in the absence of direct empirical evidence.

Woo and wooism is officially an established branch of physics now, I guess.

I can save Sabine a lot of time with this, though. Naturalness is posited that all of physics should be renormalizable to something expressible in quantum units of order unity. Well, they’re right.

It is. They’re called fundamental particles and the elements. You know them well, I presume, it’s called ‘chemistry’. In my world, I call it quantum chemistry, and underlying all that is something called arithmetic and the fundamental axioms of set theory. You see, I got the Bourbaki math in my first grade education. By the fifth grade I had seen it all. Cantor, Newton and Hilbert, et al.

So what’s the deal with these really big numbers and really small numerical values?

How could this be? Who ordered that?

Well unfortunately, in my nutshell universe there is this fundamental finite speed limit called the speed of light, denoted by the symbol c, and a fundamental unit of action commonly denoted by Planck’s constant called h. And when doing the math it’s convenient to renormalize these values to unity, h/2π = ħ = c = 1, which greatly simplifies the mathematical notation and the resulting equations. And that involves things like the numerical value of π, which being a transcendental value, requires an infinite (endless) number of numerical digits to express exactly. This kind of renormalization to unity procedure can be applied to any number of a wide variety of physical units and constants with very great success. They’re called natural units.

So problem solved! But there is another problem in my nutshell universe. The speed of light in the microscopic world is extremely fast, but in the cosmic astronomical universe it is extremely slow, so slow that a vast portion of my nutshell is now unobservable after 13.8 billion years. And get this, that speed, the speed of light, can never be attained by any macroscopic assemblage of atoms, no matter how much energy is applied, as demonstrated by both the special and general theories of relativity. You remember that guy, right? Albert Einstein? And Max Planck?

And even worse for my nutshell universe, entropy is continually created along with disorder and order in the nutshell. The integer value for that entropy just keeps getting larger and larger as the universe continues to self order and then decay into chaos as the rest of the cosmos continues to expand away from me, at speeds approaching, but never reaching, the finite speed of light.

That is, 1/n → 0 as n → ∞ and 0 ≠ 1 ≠ ∞. QED. Just be sure to trap out any division by zero.

When dealing with finite attractive forces, sooner or later something is gonna break.

Damn. I hate arithmetic already. And nature and physics sucks.

I wish Al Gore never invented the axion angle.

I’m going to become a philosopher.

The money is good, I hear.

Update: Now let’s all give a big hand for the whole, positive, real, exact integer, number 137.

Welcome back into my math cult.

Update 2: Try setting 0 = 1 and then build a mathematical framework around that relation. I tried that once, and it was moderately insightful. Or alternatively, toss out the zero, and then proceed.

That works in a fashion as well.

Update 3: Until it breaks.

Like in Star Trek.

Update 4: It’s like landing exactly on the pole in the 3D Graphics Orbital Space Flight Simulator.

There is a singularity in the math program.

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A Bulk Boundary Entanglement Entropy Information Hamiltonian

by Tommy on 12/12/2016

The John Templeton Foundation is gonna love this one.

https://arxiv.org/abs/1612.02831

Edge–Entanglement correspondence for gapped topological phases with symmetry, Maciej Koch-Janusz, Kusum Dhochak and Erez Berg (8 December 2016)

The correspondence between the edge theory and the entanglement spectrum is firmly established for the chiral topological phases. We study gapped, topologically ordered, non-chiral states with a conserved U(1) charge and show that the entanglement Hamiltonian contains not only the information about topologically distinct edges such phases may admit, but also which of them will be realized in the presence of symmetry breaking/conserving perturbations. We introduce an exactly solvable, charge conserving lattice model of a Z2 spin liquid and derive its edge theory and the entanglement Hamiltonian, also in the presence of perturbations. We construct a field theory of the edge and study its RG flow. We show the precise extent of the correspondence between the information contained in the entanglement Hamiltonian and the edge theory.

Fuzzy black hole horizon firewall here I come.

Go towards the light!

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Another Classification of Topological Crystalline Insulators

by Tommy on 12/12/2016

Here we go again.

https://arxiv.org/abs/1612.02007

Topological classification of crystalline insulators through band structure combinatorics, Jorrit Kruthoff, Jan de Boer, Jasper van Wezel, Charles L. Kane and Robert-Jan Slager (6 December 2016)

We present a method for efficiently enumerating all allowed, topologically distinct, electronic band structures within a given crystal structure. The algorithm applies to crystals with broken time-reversal, particle-hole, and chiral symmetries in any dimension. The presented results match the mathematical structure underlying the topological classification of these crystals in terms of K-theory, and therefore elucidate this abstract mathematical framework from a simple combinatorial perspective. Using a straightforward counting procedure, we classify the allowed topological phases in any possible two-dimensional crystal in class A. We also show how the same procedure can be used to classify the allowed phases for any three-dimensional space group. Employing these classifications, we study transitions between topological phases within class A that are driven by band inversions at high symmetry points in the first Brillouin zone. This enables us to list all possible types of phase transitions within a given crystal structure, and identify whether or not they give rise to intermediate Weyl semimetallic phases.

So much math, so little stuff.

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NORDITA Stockholm University Dark Matter Axion Conference

by Tommy on 9/12/2016

Frank Wilczek hosts first workshop on axions as professor at Stockholm University

https://www.eurekalert.org/pub_releases/2016-12/su-fwh120516.php

Axion Dark Matter Workshop Conference – NORDITA – Stockholm University

http://agenda.albanova.se/conferenceDisplay.py?confId=5859

Axion Dark Matter Workshop Conference Timetable

https://www.nordita.org/timetables/?confid=5859

Today is the discussion day.

It should be over now.

All hail the probe.

Update: There is a reason they are doing this in Stockholm on the eve of the Nobel Prize ceremony. Hopefully Vera Rubin will make it through the year. Rubin, Quinn and Peccei.

For chemistry … be prepared for the greatest cosmic QCD axion surprise ever.

Coming soon to a Blob near you.

Update 2: Chemistry is mine to take, apparently. Knowing me, I’ll be late to the ceremony.

Well, there’s always next year, I guess. Vera Rubin does not have that luxury anymore.

Update 3: I’m pretty sure that if I was invited I would make a point of attending.

A lot of very nice people were waiting for you to perform, Dr. Bob Dylan.

You’re a performer right? An artist? Even when I’m wrong, I show up.

Update 4: Vera Rubin Passed Away on Christmas Day Evening on December 25th, 2016.

Update 5: http://lifeform.net/archimedes/Cosmic_Axions.pdf

Gravitational Axions as Dark Matter

Update 6: http://lifeform.net/archimedes/Quantum_Cosmology.pdf

Gravitational Axions in Quantum Gravity and Cosmology

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Mechanical Diamond Model of Topological Physics

by Tommy on 9/12/2016

Here is a very cool idea.

https://arxiv.org/abs/1612.02614

Edge states of mechanical diamond and its topological origin, Yuta Takahashi, Toshikaze Kariyado and Yasuhiro Hatsugai (8 December 2016)

A mechanical diamond, a classical mechanics of a spring-mass model arrayed on a diamond lattice, is discussed topologically. Its frequency dispersion possesses an intrinsic nodal structure in the three-dimensional Brillouin zone (BZ) protected by the chiral symmetry. Topological changes of the line nodes are demonstrated associated with modification of the tension. The line nodes projected into two-dimensional BZ form loops which are characterized by the quantized Zak phases by 0 and π. With boundaries, edge states are discussed in relation to the Zak phases and winding numbers. It establishes a bulk-edge correspondence of the mechanical diamond.

And what a wonderful exposition of their results.

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Interstitial Inter Galactic Dark Matter is Somewhat Smooth

by Tommy on 7/12/2016
Galactic Dark Matter Interstitial Voids

Galactic Dark Matter Interstitial Voids

This is getting a lot of press, mostly misinterpretive.

http://mnras.oxfordjournals.org/content/465/2/1454.abstract

http://www.eso.org/public/archives/releases/sciencepapers/eso1642/eso1642a.pdf

KiDS-450: Cosmological parameter constraints from tomographic weak gravitational lensing, H. Hildebrandt, et al., and the KiDS Collarboration, Monthly Notices of the Royal Astronomical Society, MNRAS, 465, 2, 1454-1498 (21 February 2017), doi:10.1093/mnras/stw2805

We present cosmological parameter constraints from a tomographic weak gravitational lensing analysis of ∼450 deg2 of imaging data from the Kilo Degree Survey (KiDS). For a flat Λ cold dark matter (ΛCDM) cosmology with a prior on H0 that encompasses the most recent direct measurements, we find S8 ≡ σ8 √Ωm/0.3 = 0.745 ± 0.039. This result is in good agreement with other low-redshift probes of large-scale structure, including recent cosmic shear results, along with pre-Planck cosmic microwave background constraints. A 2.3σ tension in S8 and ‘substantial discordance’ in the full parameter space is found with respect to the Planck 2015 results. We use shear measurements for nearly 15 million galaxies, determined with a new improved ‘self-calibrating’ version of lensfit validated using an extensive suite of image simulations. Four-band ugri photometric redshifts are calibrated directly with deep spectroscopic surveys. The redshift calibration is confirmed using two independent techniques based on angular cross-correlations and the properties of the photometric redshift probability distributions. Our covariance matrix is determined using an analytical approach, verified numerically with large mock galaxy catalogues. We account for uncertainties in the modelling of intrinsic galaxy alignments and the impact of baryon feedback on the shape of the non-linear matter power spectrum, in addition to the small residual uncertainties in the shear and redshift calibration. The cosmology analysis was performed blind. Our high-level data products, including shear correlation functions, covariance matrices, redshift distributions, and Monte Carlo Markov chains are available at http://kids.strw.leidenuniv.nl.

I apologize that I not longer have time for long author lists and extensive HTML formatting of complex abstracts. Sorry. This is not an unexpected result for me. I’ll need to read it, though.

Meanwhile I will continue to smoove you with my theory of gravitational dark matter axions.

Just call me The Smoove.

I will smoove you.

I’m smoooovy.

Smoove me!

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Hall Viscosity and Drag for Effective Mass in Superfluids

by Tommy on 7/12/2016

This is a remarkably different perspective on this matter.

https://arxiv.org/abs/1612.01547

Transport in Superfluid Mixtures, Michael Geracie (5 December 2016)

We present a general method for constructing effective field theories for non-relativistic superfluids, generalizing the previous approaches of Greiter, Witten, and Wilczek, and Son and Wingate to the case of several superfluids in solution. We investigate transport in mixtures with broken parity and find a parity odd “Hall drag” in the presence of independent motion as well as a pinning of mass, charge, and energy to sites of nonzero relative velocity. Both effects have a simple geometric interpretation in terms of the signed volumes and directed areas of various sub-complexes of a “velocity polyhedron”: the convex hull formed by the endpoints of the velocity vectors of a superfluid mixture. We also provide a simple quasi-one-dimensional model that exhibits non-zero Hall drag.

Read it, and grok it (or at least try), even when life itself is a drag.

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Quantum Critical Point Behavior in Simple Lattice Models

by Tommy on 7/12/2016

Asymptopia is my new favorite word for the day.

https://arxiv.org/abs/1612.01542

Superconductivity and bad metal behavior near a nematic quantum critical point, Samuel Lederer, Yoni Schattner, Erez Berg and Steven A. Kivelson
(5 December 2016)

Using determinantal quantum Monte Carlo, we compute the properties of a lattice model with spin 1/2 itinerant electrons tuned through a quantum phase transition to an Ising nematic phase. The nematic fluctuations induce superconductivity with a broad dome in the superconducting Tc enclosing the nematic quantum critical point. For temperatures above Tc, we see strikingly non-Fermi liquid behavior including a “nodal – anti nodal dichotomy” reminiscent of that seen in several transition metal oxides and “bad metal” behavior of the conductivity.

Bad metal. Very Bad Metal!

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Topological Space Group Symmetries Catagorized

by Tommy on 6/12/2016

https://arxiv.org/abs/1612.00846

Gauging spatial symmetries and the classification of topological crystalline phases, Ryan Thorngren and Dominic V. Else (2 December 2016)

We put the theory of interacting topological crystalline phases on a systematic footing. These are topological phases protected by space-group symmetries. Our central tool is an elucidation of what it means to “gauge” such symmetries. We introduce the notion of a “topological crystalline liquid”, and argue that most (and perhaps all) phases of interest are likely to satisfy this criterion. We prove a Crystalline Equivalence Principle, which states that in Euclidean space, topological crystalline liquids with symmetry group G are in one-to-one correspondence with topological phases protected by the same symmetry G, but acting *internally*, where if an element of G is orientation-reversing, it is realized as an anti-unitary symmetry in the internal symmetry group. As an example, we explicitly compute, using group cohomology, a partial classification of bosonic symmetry-protected topological (SPT) phases protected by crystalline symmetries in (3+1)-D for 227 of the 230 space groups. For the 65 space groups not containing orientation-reversing elements (Sohncke groups), there are no cobordism invariants which may contribute phases beyond group cohomology, and so we conjecture our classification is complete.

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Dark Matter Curvatons in a Double Cosmic Inflation Scenario

by Tommy on 4/12/2016

It took me a while to slog through this. The model is a bit ad hoc, and the math oversimplied with lots of speculative assumptions. But I must say I like the idea of a double inflation now. The only sense I can make out of all of this is that the great fall from the Planck scale to the Higgs scale is the secondary inflation, either accompanied by or followed by the reheating of the quark gluon particle plasma flux. In this case initial inflation event represents the entire Einstein mass energy equivalent of all of the gravitational field of space (time) itself, along with all of the mass energy equivalent of the dark matter and baryons contained within it. That’s a whole lotta stuff. Wow.

https://arxiv.org/abs/1611.08975

Curvaton as dark matter with secondary inflation, Jinn-Ouk Gong, Naoya Kitajima and Takahiro Terada, APCTP Pre2016-022, KIAS-P16084 (28 November 2016)

We consider a novel cosmological scenario in which a curvaton is long-lived and plays the role of cold dark matter (CDM) in the presence of a short, secondary inflation. Non-trivial evolution of the large scale cosmological perturbation in the curvaton scenario can affect the duration of the short term inflation, resulting in the inhomogeneous end of inflation. Non-linear parameters of the curvature perturbation are predicted to be fNL ~ 5/4 and gNL ~ 0. The curvaton abundance can be well diluted by the short-term inflation and accordingly, it does not have to decay into the Standard Model particles. Then the curvaton can account for the present CDM with the isocurvature perturbation being sufficiently suppressed because both the adiabatic and CDM isocurvature perturbations have the same origin. As an explicit example, we consider the thermal inflation scenario and a string axion as a candidate for this curvaton-dark matter. We further discuss possibilities to identify the curvaton-dark matter with the QCD axion.

I have to tell you that my mind is really completely boggled now.

So I guess it’s a big bang followed by a little bang.

Followed by a whole lotta hot non-nothing.

Cool. I like this already.

Update: Followed by the giant dark matter vacuum cleaner event.

http://cosmic.lifeform.org/the-cosmic-universe-as-non-equilibrium-energy-conversion/

The Cosmic Universe as Non Equilibrium Energy Conversion

The ‘Little Bounce’.

Update 2: It’s going to take a long time for the dark matter to clean up this mess.

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Chern Simons Axion Physics Coupling Theorem Explored

by Tommy on 4/12/2016

This is a nice clean presentation of axion physics in condensed matter physics systems.

https://arxiv.org/abs/1611.08109

Surface theorem for the Chern-Simons axion coupling, Thomas Olsen, Maryam Taherinejad, David Vanderbilt and Ivo Souza (24 November 2016)

The Chern-Simons axion coupling of a bulk insulator is only defined modulo a quantum of e2/h. The quantized part of the coupling is uniquely defined for a bounded insulating sample, but it depends on the specific surface termination. Working in a slab geometry and representing the valence bands in terms of hybrid Wannier functions, we show how to determine that quantized part from the excess Chern number of the hybrid Wannier sheets located near the surface of the slab. The procedure is illustrated for a tight-binding model consisting of coupled quantum anomalous Hall layers. By slowly modulating the model parameters, it is possible to transfer one unit of Chern number from the bottom to the top surface over the course of a cyclic evolution of the bulk Hamiltonian. When the evolution of the surface Hamiltonian is also cyclic, the Chern pumping is obstructed by chiral touchings between valence and conduction surface bands.

All your model are belong to us.

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Weyl Semimetals, Fermi Arcs and Chiral Anomalies Reviewed

by Tommy on 2/12/2016

Hasan is a leader of this field, but only because his name is recognizable.

https://arxiv.org/abs/1612.00416

http://www.nature.com/nmat/journal/v15/n11/full/nmat4787.html

Weyl Semimetals, Fermi Arcs and Chiral Anomalies (A Short Review), Shuang Jia, Su-Yang Xu, and M. Zahid Hasan, Nature Materials, 15, 1140-1144 (25 October 2016), DOI:10.1038/nmat4787

Physicists have discovered a novel topological semimetal, the Weyl semimetal, whose surface features a non-closed Fermi surface while the low energy quasiparticles in the bulk emerge as Weyl fermions. Here they share a brief review of the development and present perspectives on the next step forward.

So this has been fun over the last few years.

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I Guess I am Now Officially a Science and Physics Disruptor

by Tommy on 1/12/2016
Science Physics Disruptor Disrupting Disruption

Science Physics Disruptor Disrupting Disruption

Those are my new favorite words now.

This is going to be great fun.

But it won’t be pretty.

Science never is.

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The Master’s Thesis of Molly Rebecca Sexton at Oklahoma

by Tommy on 30/11/2016

This isn’t a very definitive Master’s thesis result, and it certainly isn’t PhD grade, but it is admirable that they all took the time to look into these nanodiamonds more closely. That being said, this doesn’t bode well for the Younger Dryas boundry layer sediments and sedimentary nanodiamonds, anywhere in the sedimentary record at all, so I guess I will all have to wait for more definitive results on this subject. It would be great if anyone could definitively identify and demonstrate the existence of sedimentary nanodiamonds, besides at known impact sites.

https://shareok.org/bitstream/handle/11244/34605/2016_Sexton_Molly_Thesis.pdf?sequence=2&isAllowed=y

Statigraphic and Textural Analysis of Nanodiamonds Across the Younger Dryas Boundary Sediments of Western Oklahoma, Molly Rebecca Sexton, Master’s Thesis, Andrew Elwood Madden, Advisor, The University of Oklahoma, Norman, Oklahoma (2016)

Exposed sediment profiles of the panhandle of western Oklahoma have previously been shown to contain two peak abundances of nanodiamonds, one dated approximately to the Younger Dryas and the other from the Late Holocene. The sediments of the Bull Creek Valley contain numerous Clovis culture artifacts and megafauna remains that disappeared after the Younger Dryas Boundary Layer. Firestone et al. have proposed that the reason for this sudden disappearance is a bolide impact that broke apart in the atmosphere, scattering debris across the world (2007).

Nanodiamonds could be evidence for such an impact. In this study, I examined 12 additional samples collected at the same time as those reported by Bement et al. (2014) but not analyzed for nanodiamond content using Transmission Electron Microscopy (TEM). These samples were collected at various locations along the same Bull Creek valley, Oklahoma, including sediments older than those analyzed by Bement et al. (2014) and an additional nearby location that crosses the Younger Dryas Boundary. No nanodiamonds were found in these samples. However, the results may not be indicative of the true nanodiamond abundance. In a further test, a grid was prepared from a sediment digest solution shown by Bement et al. (2014) to have a peak abundance of nanodiamonds. No nanodiamonds were observed in this sample, suggesting that the nanodiamonds may have a finite lifetime when preserved in an ammonium hydroxide suspension. Additionally, Raman spectroscopy was investigated and ruled out as a means of screening samples for nanodiamond content more quickly and easily. Prepared samples of sediment solution previously confirmed to have nanodiamonds showed no Raman peaks associated with diamonds, though this could also have been the result of the ammonium hydroxide suspension storage. However, samples of untreated commercial nanodiamonds also did not exhibit any characteristic diamond peaks, though possible peaks may have been obscured by heavy fluorescence.

Finally, the samples that were confirmed by Bement et al. (2014) to have nanodiamonds were divided into groups based on the ages of their sediments and highresolution (HRTEM) images of them were examined for the textures of individual grains in order to gain a better insight of how they may have formed. The textures were categorized as having no lattice fringes, partial fringes, continuous fringes, linear twins, nonlinear twins, or star twins. The nanodiamond grains in the Younger Dryas Boundary group had the lowest ratio of linear to nonlinear grains and one of the highest ratios of star twins to twins, both of which are indicative of a chemical vapor deposition formation mechanism.

This is the first study to analyze and compare nanodiamond textures from the same stratigraphic area. The differences found between the older and younger nanodiamonds suggests that further studies comparing textures across spatial and temporal boundaries could lead to more definite signatures indicative of their origins.

It’s a start, again, I guess. Hopefully she will look at it again, for her PhD.

Unless, of course, sedimentary impact nanodiamonds don’t exist.

That could very well be true, but I don’t see how.

Maybe they just all burn up in the air.

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Formal Gravitationally Induced Quantum Thermal Hall Effect

by Tommy on 30/11/2016

And here is the breakthrough. I’m cracking up. Again. Only formally now. Over.

https://arxiv.org/abs/1611.09463

Laughlin’s argument for the quantized thermal Hall effect, Ryota Nakai, Shinsei Ryu and Kentaro Nomura (29 November 2016)

We extend Laughlin’s magnetic-flux-threading argument to the quantized thermal Hall effect. A proper analogue of Laughlin’s adiabatic magnetic-flux threading process for the case of the thermal Hall effect is given in terms of an external gravitational field. From the perspective of the edge theories of quantum Hall systems, the quantized thermal Hall effect is closely tied to the breakdown of large diffeomorphism invariance, that is, a global gravitational anomaly. In addition, we also give an argument from the bulk perspective in which a free energy, decomposed into its Fourier modes, is adiabatically transferred under an adiabatic process involving external gravitational perturbations.

I can only suggest you give this a very careful reading.

Like I will do when I have the time.

I mean space. Or energy.

It doesn’t matter.

See also: http://iopscience.iop.org/article/10.1088/1367-2630/18/2/023038

Finite-temperature effective boundary theory of the quantized thermal Hall effect, Ryota Nakai, Shinsei Ryu and Kentaro Nomura, New Journal of Physics, Volume 18 (10 February 2016)

A finite-temperature effective free energy of the boundary of a quantized thermal Hall system is derived microscopically from the bulk two-dimensional Dirac fermion coupled with a gravitational field. In two spatial dimensions, the thermal Hall conductivity of fully gapped insulators and superconductors is quantized and given by the bulk Chern number, in analogy to the quantized electric Hall conductivity in quantum Hall systems. From the perspective of effective action functionals, two distinct types of the field theory have been proposed to describe the quantized thermal Hall effect. One of these, known as the gravitational Chern–Simons action, is a kind of topological field theory, and the other is a phenomenological theory relevant to the Strěda formula. In order to solve this problem, we derive microscopically an effective theory that accounts for the quantized thermal Hall effect. In this paper, the two-dimensional Dirac fermion under a static background gravitational field is considered in equilibrium at a finite temperature, from which an effective boundary free energy functional of the gravitational field is derived. This boundary theory is shown to explain the quantized thermal Hall conductivity and thermal Hall current in the bulk by assuming the Lorentz symmetry. The bulk effective theory is consistently determined via the boundary effective theory.

So quantum gravity is something like a thermal gradient.

The takeaway is that gravitons are diffusive.

This article is open access.

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Theory of Learning Subjected to Stochastic Thermodynamics

by Tommy on 30/11/2016

It’s more costly to learn from stored information than it is to store that information.

https://arxiv.org/abs/1611.09428

Stochastic Thermodynamics of Learning, Sebastian Goldt and Udo Seifert (November 2016)

Virtually every organism gathers information about its noisy environment and builds models from that data, mostly using neural networks. Here, we use stochastic thermodynamics to analyse the learning of a classification rule by a neural network. We show that the information acquired by the network is bounded by the thermodynamic cost of learning and introduce a learning efficiency η ≤ 1. We discuss the conditions for optimal learning and analyse Hebbian learning in the thermodynamic limit.

Who is Udo Seifert again? Didn’t he just win a Breakthrough Prize?

Some things are difficult to forget.

It takes too much energy.

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