Topological Insulator Surface States Disentangled from the Bulk

by Tommy on 17/01/2017
Magneto Infrared Spectroscopy Faraday Rotation Topological Insulators

Magneto Infrared Spectroscopy Faraday Rotation Topological Insulators

https://arxiv.org/abs/1701.02403

http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b04313

Faraday rotation due to surface states in the topological insulator (Bi1−xSbx)2Te3, Yinming Shao, Kirk W. Post, Jhih-Sheng Wu, Siyuan Dai, Alex J. Frenzel, Anthony R. Richardella, Joon Sue Lee, Nitin Samarth, Michael M. Fogler, Alexander V. Balatsky, Dmitri E. Kharzeev and D. N. Basov, Nano Lett. (29 December 2016)

Using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. The FR data uncovered that electron- and hole-type Dirac fermions reside on opposite surfaces of our films, which paves the way for observing many exotic quantum phenomena in topological insulators.

These the million dollar takeaway quotes.

This hypothesis has implications for the finite frequency response of a TI: a resonance mode can be anticipated in infrared frequencies, offering yet another opportunity to investigate the condensed matter manifestations of phenomena discussed in high energy physics. The search for such resonances remains a challenge for future theoretical and experimental studies of 3D-TIs as well as Dirac/Weyl semimetals in magnetic field.

Such separated n- and p-type Dirac fermions paves the way for the observation of exotic quantum phenomena in TI, such as topological magneto-electric effect and topological exciton condensation.

In other words, this paves the way to solid state axion production, emission and detection.

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ARPES Investigation Demonstrates Nontrivial Bismuth Topology

by Tommy on 17/01/2017

The world is starting to wake up to the possibilities of bismuth, apparently.

https://arxiv.org/abs/1605.03531

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.236402

Proving Nontrivial Topology of Pure Bismuth by Quantum Confinement, S. Ito, B. Feng, M. Arita, A. Takayama, R.-Y. Liu, T. Someya, W.-C. Chen, T. Iimori, H. Namatame, M. Taniguchi, C.-M. Cheng, S.-J. Tang, F. Komori, K. Kobayashi, T.-C. Chiang and I. Matsuda, Phys. Rev. Lett. 117, 236402 (2 December 2016), doi:10.1103/PhysRevLett.117.236402

The topology of pure Bi is controversial because of its very small (∼10 meV) band gap. Here we perform high-resolution angle-resolved photoelectron spectroscopy measurements systematically on 14−202 bilayers Bi films. Using high-quality films, we succeed in observing quantized bulk bands with energy separations down to ∼10 meV. Detailed analyses on the phase shift of the confined wave functions precisely determine the surface and bulk electronic structures, which unambiguously show nontrivial topology. The present results not only prove the fundamental property of Bi but also introduce a capability of the quantum-confinement approach.

Or rather, finally.

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Dark Matter Halos are Capable of Stripping Galaxies of Gas

by Tommy on 17/01/2017

This result clearly indicates the particulate nature of dark matter axions.

This doesn’t bode well for modified gravity theories of dark matter.

https://arxiv.org/abs/1611.00896

https://academic.oup.com/mnras/article-abstract/466/2/1275/2556147/Cold-gas-stripping-in-satellite-galaxies-from?redirectedFrom=fulltext

http://s3-ap-southeast-2.amazonaws.com/icrar.org/wp-content/uploads/2016/12/11085410/Ram-Pressure-Stripping-Paper.pdf

Cold gas stripping in satellite galaxies: from pairs to clusters, Toby Brown, Barbara Catinella, Luca Cortese, Claudia del P. Lagos, Romeel Dave, Virginia Kilborn, Martha P. Haynes, Riccardo Giovanelli and Mika Rafieferantsoa, MNRAS, 466, 2, 1275-1289 (16 January 2017) doi:10.1093/mnras/stw2991

In this paper we investigate environment driven gas depletion in satellite galaxies, taking full advantage of the atomic hydrogen (HI) spectral stacking technique to quantify the gas content for the entire gas-poor to -rich regime. We do so using a multi-wavelength sample of 10,600 satellite galaxies, selected according to stellar mass (log M/M ≥ 9) and redshift (0.02 ≤ z ≤ 0.05) from the Sloan Digital Sky Survey, with HI data from the Arecibo Legacy Fast ALFA (ALFALFA) survey. Using key HI-to-stellar mass scaling relations, we present evidence that the gas content of satellite galaxies is, to a significant extent, dependent on the environment in which a galaxy resides. For the first time, we demonstrate that systematic environmental suppression of gas content at both fixed stellar mass and fixed specific star formation rate (sSFR) in satellite galaxies begins in halo masses typical of the group regime (log Mh/M < 13.5), well before galaxies reach the cluster environment. We also show that environment driven gas depletion is more closely associated to halo mass than local density. Our results are then compared with state-of-the-art semi-analytic models and hydrodynamical simulations and discussed within this framework, showing that more work is needed if models are to reproduce the observations. We conclude that the observed decrease of gas content in the group and cluster environments cannot be reproduced by starvation of the gas supply alone and invoke fast acting processes such as ram-pressure stripping of cold gas to explain this.

See also: https://arxiv.org/abs/1701.01754

xGASS: Gas-rich central galaxies in small groups and their connections to cosmic web gas feeding, Steven Janowiecki, Barbara Catinella, Luca Cortese, Amélie Saintonge, Toby Brown and Jing Wang, Accepted to MNRAS (6 January 2017)

We use deep HI observations obtained as part of the extended GALEX Arecibo SDSS survey (xGASS) to study the cold gas properties of central galaxies across environments. We find that, below stellar masses of 1010.2 M, central galaxies in groups have an average atomic hydrogen gas fraction ~ 0.3 dex higher than those in isolation at the same stellar mass. At these stellar masses, group central galaxies are usually found in small groups of N = 2 members. The higher HI content in these low mass group central galaxies is mirrored by their higher average star formation activity and molecular hydrogen content. At larger stellar masses, this difference disappears and central galaxies in groups have similar (or even smaller) gas reservoirs and star formation activity compared to those in isolation. We discuss possible scenarios able to explain our findings and suggest that the higher gas content in low mass group central galaxies is likely due to contributions from the cosmic web or HI-rich minor mergers, which also fuel their enhanced star formation activity.

ICRAR Press Release: http://www.icrar.org/galaxy-murder-mystery/

News Corp Australia Network Story

Probing the Cosmic Blobs.

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The Ground State and Excitation Spectrum of Quantum Bosons

by Tommy on 16/01/2017

This speaks volumes on the fundamental nature of dark matter axions as quantum bosons.

https://arxiv.org/abs/1701.03676

Emergent orders for bosonic atoms with competing short- and global-range interactions in an optical lattice, Renyuan Liao (13 January 2017)

We consider bosonic atoms loaded into optical lattices with cavity-mediated infinite-range interactions. Competing short- and global-range interactions cultivates a rich phase diagram. With a systematic field-theoretical perspective, we present an analytical construction of global ground-state phase diagram. We derive an effective theory describing compressible superfluid and supersolid states. We show that global-range interactions enhances density fluctuations and tunneling.

See also: https://arxiv.org/abs/1701.03673

http://iopscience.iop.org/article/10.1088/1367-2630/aa559b/meta;jsessionid=68657D4BFC8F58393DC7E047364E40E5.c1.iopscience.cld.iop.org

Bose-Einstein condensates in the presence of Weyl spin-orbit coupling, Ting Wu and Renyuan Liao, New Journal of Physics, 19, 13008 (11 January 2017), doi:10.1088/1367-2630/aa559b

We consider two-component Bose-Einstein condensates subject to Weyl spin-orbit coupling. We obtain mean-field ground state phase diagram by variational method. In the regime where interspecies coupling is larger than intraspecies coupling, the system is found to be fully polarized and condensed at a finite momentum lying along the quantization axis. We characterize this phase by studying the excitation spectrum, the sound velocity, the quantum depletion of condensates, the shift of ground state energy, and the static structure factor. We find that spin-orbit coupling and interspecies coupling generally leads to competing effects.

It’s all good now.

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Quantum Cosmology PhD Thesis of Andre Franca at Munich

by Tommy on 14/01/2017

This is very much a must read PhD thesis and the best I have seen for some time now.

https://edoc.ub.uni-muenchen.de/19956/

https://edoc.ub.uni-muenchen.de/19956/1/Andre_Franca.pdf

Quantum Many-Body Effects in Gravity and Bosonic Theories, Andre Franca, PhD Thesis Dissertation, Ludwig Maximilian University of Munich, Giorgi Dvali, Advisor (13 July 2016)

Many-body quantum effects play a crucial role in many domains of physics, from condensed matter to black-hole evaporation. The fundamental interest and difficulty in studying this class of systems is the fact that their effective coupling constant become rescaled by the number of particles involved g = αN, and thus we observe a breakdown of perturbation theory even for small values of the 2 → 2 coupling constant. We will study three very different systems which share the property that their behaviour is dominated by non-perturbative effects. The strong CP problem – the problem of why the ϴ angle of QCD is so small – can be solved by the Peccei-Quinn mechanism, which promotes the ϴ angle to a physical particle, the axion. The essence of the PQ mechanism is that the coupling will generate a mass gap, and thus the expectation value of the axion will vanish at the vacuum. It has been suggested that topological effects in gravity can spoil the axion solution. By using the dual formulation of the Peccei-Quinn mechanism, we are able to show that even in the presence of such dangerous contributions from gravity, the presence of light neutrinos can stabilize the axion potential. This effect also puts an upper bound on the lightest neutrino mass. We know that at high energies, gravitational scattering is dominated by black-hole formation. The typical size of black-holes is a growing function of the total center-of-mass energy involved in the scattering process. In the asymptotic future, these black-holes will decay into Hawking radiation, which has a typical wave-length of the size of the black-hole. Thus high energy gravitational scattering is dominated by low energy out states. It has been suggested that gravity is self-complete due to this effect, and that furthermore, there is a class of bosonic theories which can also be self-complete due to the formation of large classical field configurations: UV completion by Classicalization. We explore the idea of Classicalization versus Wilsonian UV completion in derivatively coupled scalars. We seek to answer the following question: how does the theory decide which road to take at high energies? We find out that the information about the high energy behaviour of the theory is encoded in the sign of the quartic derivative coupling. There is one sign that allows for a consistent Wilsonian UV-completion, and another sign that contains continuous classical field configurations for localized sources.

In the third part of the thesis we explore non-perturbative properties of black holes. We consider the model proposed by Dvali and Gomez where black holes are described as Bose-Einstein condensates N gravitons. These gravitons are weakly interacting, however their collective coupling constant puts them exactly at the critical point of a quantum phase transition αN = 1. We focus on a toy model which captures some of the features of information storage and processing of black holes. The carriers of information and entropy are the Bogoliubov modes, which we are able to map to pseudo-Goldstone bosons of a broken SU(2) symmetry. At the quantum phase transition this gap becomes 1/N, which implies that the cost of information storage disappears in the N → ∞ limit. Furthermore, the storage capacity and lifetime of the modes increases with N, becoming infinite in the N → ∞ limit. The attractive Bose gas which we considered is integrable in 1+1d. All the eigenstates of the system can be constructed using the Bethe ansatz, which transforms the Hamiltonian eigenvalue problem into a set of algebraic equations – the Bethe equations – for N parameters which play the role of generalize momenta. While the ground state and excitation spectrum are known in the repulsive regime, in the attractive case the system becomes more complicated due to the appearance of bound states. In order to solve the Bethe equations, we restrict ourselves to the N → ∞ limit and transform the algebraic equations into a constrained integral equation. By solving this integral equation, we are able to study the phase transition from the point of view of the Bethe ansatz. We observe that the phase transition happens precisely when the constraint is saturated, and manifests itself as a change in the functional form of the density of momenta. Furthermore, we are able to show that the ground state of this system can be mapped to the saddle-point equation of 2-dimensional Yang–Mills on a sphere, with a gauge group U(N).

Suffice it to say it will take me some time to work through these last two papers.

But unfortunately, I’m committed to this thing now.

Quantum gravity gauge field theory.

What a mess this is.

Update: Andre Franca is much smarter than his advisors and professors, and they know that.

Andre is smarter than me too, but I’m also smart enough to know that.

This is a breakthroughy body of work I don’t have to do.

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Primordial Gravitational Axion Gauge Field Cosmology Probed

by Tommy on 14/01/2017

These are long and complicated but state of the art precision cosmological arguments here.

https://arxiv.org/abs/1612.05701

Tensor Adiabatic Modes and Consistency Relations with Primordial Axion-Gauge Fields, Azadeh Maleknejad, Prepared for Submission to the Journal of High Energy Physics (JHEP)
(17 December 2016)

We study the tensor consistency relation in models of axion inflation with an SU(2) gauge field. In the tensor sector, we have two spin-2 modes, the standard gravity waves and the tensor perturbations of the SU(2) gauge field which sources the gravity waves at the linear level. Interestingly enough, we find that the gravity waves are adiabatic and Maldacena’s consistency relation including a long wavelength gravity wave holds in this setup. However, since it is partially polarized, there is a difference between the (n+1)-point functions with different helicity states proportional to the ratio of the gauge field density to the total density. These chiral n-point functions are the imprints of the SU(2) gauge field on the primordial cosmological perturbations and a robust observational feature of their contribution to the physics of inflation.

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Dark Matter BEC Halos Compared To Galaxy Rotation Rates

by Tommy on 12/01/2017

This seems fairly definitive.

https://arxiv.org/abs/1406.0388

http://downloads.hindawi.com/journals/ahep/aip/4025386.pdf

Bose-Einstein Condensate Dark Matter Halos confronted with galactic rotation curves, M. Dwornik, Z. Keresztes, E. Kun and L. A. Gergely, Institute of Physics, University of Szeged, Dom Ter 9, Szeged 6720, Hungary (29 October 2016)

We present a comparative confrontation of both the Bose-Einstein Condensate (BEC) and the Navarro-Frenk-White (NFW) dark halo models with galactic rotation curves. We conclude that the BEC model fits better the dwarf galaxy dark matter distribution, but suffers from sharp cut-off in larger galaxies, where the NFW model performs better. In more detail, we employ High Surface Brightness (HSB), Low Surface Brightness (LSB) and dwarf galaxies with rotation curves falling into two classes, based on their shapes. In the first class the rotational velocities increase with radius over the whole observed range, the BEC and NFW models giving comparable fits for both HSB and LSB galaxies, while significantly improving over the NFW fit for dwarf galaxies. This improvement is due to the central density cusp avoidance property of the BEC model. The rotational velocity of HSB and LSB galaxies falling into the second class exhibit long at plateaus, resulting in a better fit of the NFW model for HSB galaxies, and comparable fits for LSB galaxies. The weaker performance of the BEC model for the HSB type II galaxies is due to the BEC density profiles dropping rapidly to zero outside a nearly constant density core. The investigated galaxy sample obeys the Tully-Fisher relation, including the particular characteristics exhibited by dwarf galaxies. We also show that in both dark matter models the fitting enforces a relation between the dark matter parameters: the characteristic density scales inversely with the corresponding characteristic distance.

So its basically game over for everything except the microwave axion.

Only the string theory community is holding this up now.

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Dense, Strongly Coupled and Correlated Exciton Condensation

by Tommy on 11/01/2017

I’ve been reporting on exciton plasma physics for a while here.

Here is something that may directly apply to dark matter as well.

https://arxiv.org/abs/1701.02598

Condensation to a strongly correlated dark fluid of two dimensional dipolar excitons, Yotam Mazuz-Harpaz, Kobi Cohen and Ronen Rapaport (10 January 2017)

Recently we reported on the condensation of cold, electrostatically trapped dipolar excitons in GaAs bilayer heterostructure into a new, dense and dark collective phase. Here we analyze and discuss in detail the experimental findings and the emerging evident properties of this collective liquid-like phase. We show that the phase transition is characterized by a sharp increase of the number of non-emitting dipoles, by a clear contraction of the fluid spatial extent into the bottom of the parabolic-like trap, and by spectral narrowing. We extract the total density of the condensed phase which we find to be consistent with the expected density regime of a quantum liquid. We show that there are clear critical temperature and excitation power onsets for the phase transition and that as the power further increases above the critical power, the strong darkening is reduced down until no clear darkening is observed. At this point another transition appears which we interpret as a transition to a strongly repulsive yet correlated eh plasma. Based on the experimental findings, we suggest that the physical mechanism that may be responsible for the transition is a dynamical final-state stimulation of the dipolar excitons to their dark spin states, which have a long lifetime and thus support the observed sharp increase in density. Further experiments and modeling will hopefully be able to unambiguously identify the physical mechanism behind these recent observations.

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QCD and Electroweak Vacuum θ-Term Axion Angle Inheritance

by Tommy on 9/01/2017

This is exactly what I was looking for!

https://arxiv.org/abs/1701.00467

(In)dependence of Theta in the Higgs Regime without Axions, Mikhail Shifman and Arkady Vainshtein (2 January 2017)

We revisit the issue of the vacuum angle theta dependence in weakly coupled (Higgsed) Yang-Mills theories. Two most popular mechanisms for eliminating physical theta dependence are massless quarks and axions. Anselm and Johansen noted that the vacuum angle θ, associated with the electroweak SU(2) in the Glashow-Weinberg-Salam model, is unobservable although all fermion fields obtain masses through Higgsing and there is no axion. We generalize this idea to a broad class of Higgsed Yang-Mills theories.

In the second part we consider consequences of Grand Unification. We start from a unifying group, e.g. SU(5), at a high ultraviolet scale and evolve the theory down within the Wilson procedure. If on the way to infrared the unifying group is broken down into a few factors, all factor groups inherit one and the same theta angle – that of the unifying group. We show that embedding the SM in SU(5) drastically changes the Anselm-Johansen conclusion: the electroweak vacuum angle θEW, equal to θQCD becomes in principle observable in ∆B = ∆L

See also: https://arxiv.org/abs/hep-ph/9305271

Can Electro-Weak θ-Term be Observable?, A. A. Anselm and A. A.Johansen (14 May 1993)

We rederive and discuss the result of the previous paper that in the standard model θ-term related to W-boson field can not be induced by weak instantons. This follows from the existence of the fermion zero mode in the instanton field even when Yukawa couplings are switched on and there are no massless particles. We consider the new index theorem connecting the topological charge of the weak gauge field with the number of fermion zero modes of a certain differential operator which depends not only on gauge but also on Higgs fields. The possible generalizations of the standard model are discussed which lead to nonvanishing weak θ-term. In SU(2)L × SU(2)R model the θ dependence of the vacuum energy is computed.

Ok then! Off we go. I feel I am onto something now.

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Monoverse, Multiverse or Universe? Pick Any Two of Three.

by Tommy on 8/01/2017

So I finished up part one of the quantum cosmology essay, and then I ran across this meme.

I’m not sure who specifically thought that one up, but I can at least stop speculating for a while since I have now written down parts of the tangled web I have woven for myself since I simply tried to find a ZT=3 thermoelectric device a year or more ago now. In retrospect, I probably should have stuck with that. It was doing well even before the axion suddenly announced its dramatic appearance in my world of condensed matter physics. This is always serendipitous.

In the interim, I have solved the origin of life problem, which James Crutchfield promptly proved mathematically, then I went on to outline a new hypothesis for dark matter. And then I created an entire new branch of physics, quantum cosmology, from what I learned from my axion research experience. Now I am stuck with it. It needs to become mathematics. And even worse, before I can do that, I need to physically detect it, and then take a look at some of its physical properties.

Beyond its apparent effective particle mass.

I’m screwed. I’m totally screwed. I hate axions.

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

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

Gravitational Axions in Quantum Gravity and Cosmology

Gravitational Axions as Dark Matter

Remember to buy my book!

Tommy. The Legend.

In his own mind.

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Desperate MACHO WIMPs Plead For More Dark Matter Pork

by Tommy on 7/01/2017

I could see this coming light years away.

https://arxiv.org/abs/1701.00119

Dark Matter Overview, N. Fornengo, XXV ECRS 2016 Proceedings, eConf C16-09-04.3 (3 January 2017)

Identification of a solution to the dark matter problem has many arrows to its bow: if dark matter is a new elementary particle, both laboratory experiments and astrophysics can bring relevant and complementary pieces of information, that than can be confronted and composed to solve this intriguing puzzle. Although we currently do not have a unique and obvious target for the DM particle, we can rely on a broad range of ideas, tools and methods that make the investigation of dark matter a multi-frequency, multi-messenger and multi-techniques integrated endeavour.

We have BOTH kinds here, Dark Money AND Black Money.

Mo money, mo money, mo money!

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Dark Matter Gravitational Axions in Quantum Cosmology

by Tommy on 5/01/2017

Ok, so I had to whack pages of essay and brain storming after I recovered from the holidays.

Gravitational Axions in Quantum Gravity and Cosmology

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

So I looked it up and it turns out some other guy already invented it, a loop gravity guy.

But what about the Little Bounce Model. I still get that one, right?

A hypothesis was proposed for cosmic QCD axions as gravitational bosons within quantum gravity; physical gravitational analogues of Goldstone bosons coupled to artificial Higgs mode excitations as known in condensed matter physics systems; essentially low mass, low frequency and low temperature bosons of either a single species, a distribution of particle mass, or spectrum of particle mass coupling. The masses of the hypothetical dark matter particles are expected to be in the microwave region and therefore it’s possible the boson itself could be a mass mediator akin to a gravitational gauge boson.

Extending these concepts to spacetime and gravitation, and thus cosmic axions and the quantization of gravitational forces and fields, quantum gravity, involves introducing the concepts of geometry and topology from condensed matter physics analogue systems for reference, into quantum cosmology.

The purpose of this essay is to delve deeper into these new speculative quantum cosmologies based upon these concepts. Specifically I will discuss the novel concepts of axion fa field dependencies, and microwave axions as electromagnetic mass mediators within infrared and optical state transitions.

That’s puttin it out there, right? I don’t want to go full on crackpot.

It will be a while before this goes live.

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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.

No Comments

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.

No Comments

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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