A Credible Gauge Field Theory For My Cosmic QCD Axion

by Tommy on 20/01/2017

Thomas Applequist has always been ahead of the field. Or in this case, the curve.

https://arxiv.org/abs/hep-ph/0612361

http://journals.aps.org/prd/abstract/10.1103/PhysRevD.75.073005

SU(3) family gauge symmetry and the axion, Thomas Appelquist, Yang Bai and Maurizio Piai, Phys. Rev. D 75, 073005 (5 April 2007), doi:10.1103/PhysRevD.75.073005

We analyze the structure of a recently proposed effective field theory (EFT) for the generation of quark and lepton mass ratios and mixing angles, based on the spontaneous breaking of an SU(3) family gauge symmetry at a high scale F. We classify the Yukawa operators necessary to seed the masses, making use of the continuous global symmetries that they preserve. One global U(1), in addition to baryon number and electroweak hypercharge, remains unbroken after the inclusion of all operators required by standard model fermion phenomenology. An associated vacuum symmetry insures the vanishing of the first-family quark and charged-lepton masses in the absence of the family gauge interaction. If this U(1) symmetry is taken to be exact in the EFT, broken explicitly by only the QCD-induced anomaly, and if the breaking scale F is taken to lie in the range 109–1012 GeV, then the associated Nambu-Goldstone boson is a potential QCD axion.

This does seem to fit, but I will have to work through it since things have changed since then.

The Higgs boson and all that. This will take a while to work through.

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Elon Musk to Donald Trump – Thunderbirds Are Go!

by Tommy on 19/01/2017

I’m feeling kinda smug and snarky after dark matter axions. I am watching this movie now.

I can’t remember a bit of it, although I know I saw it. Thunderbirds were my saving grace during lunch hour, in the fifth grade of my barren post Star Trek youth, not relieved until it went into late afternoon syndication when I was in high school. They actually didn’t go into space much until the movie came out. The Mars Bar Guitar scene was dreamy. I wanna be a Mars Bar Guitarist!

http://nymag.com/daily/intelligencer/2017/01/donald-trump-is-reportedly-thinking-about-going-to-mars.html?mid=full-rss-di

Donald Trump Is Reportedly Thinking About Going to Mars — or Maybe Just the Moon

https://www.washingtonpost.com/news/speaking-of-science/wp/2017/01/19/will-trump-echo-jfks-moonshot-and-vow-to-send-humans-to-mars/?utm_term=.e46ddcf8cf81

Will Trump echo JFK’s moonshot and vow to send humans to Mars?

Where have I heard this before. When have I heard this before?

I wanna be first! And get this, I’m expendable!

So I only need a one way ticket.

You’ll be glad to see me go.

Update 1: My girlfriend just told me ‘Don’t expect me to come to the launch’.

Update 2: I just finished watching Thunderbird 6.

Thunderbirds are not go.

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Distant Dwarf Galaxy Groups Confirm Dark Matter Dynamics

by Tommy on 19/01/2017

The observational astronomical evidence for dark matter particles continues to pile up.

This has been out for a week so now. I saw it repeated on Lawyer Herald of all places.

https://arxiv.org/abs/1701.01731

Direct evidence of hierarchical assembly at low masses from isolated dwarf galaxy groups, Sabrina Stierwalt, Sandra E. Liss, Kelsey E. Johnson, David R. Patton, George C. Privon, Gurtina Besla, Nitya Kallivayalil and Mary Putman, Accepted for Publication in Nature Astronomy (6 January 2017)

The demographics of dwarf galaxy populations have long been in tension with predictions from the Cold Dark Matter (CDM) paradigm. If primordial density fluctuations were scale-free as predicted, dwarf galaxies should themselves host dark matter subhaloes, the most massive of which may have undergone star formation resulting in dwarf galaxy groups. Ensembles of dwarf galaxies are observed as satellites of more massive galaxies, and there is observational and theoretical evidence to suggest that these satellites at z=0 were captured by the massive host halo as a group. However, the evolution of dwarf galaxies is highly susceptible to environment making these satellite groups imperfect probes of CDM in the low mass regime. We have identified one of the clearest examples to date of hierarchical structure formation at low masses: seven isolated, spectroscopically confirmed groups with only dwarf galaxies as members. Each group hosts 3-5 known members, has a baryonic mass of ~4.4 x 109 to 2 x 1010 Msun, and requires a mass-to-light ratio of <100 to be gravitationally bound. Such groups are predicted to be rare theoretically and found to be rare observationally at the current epoch and thus provide a unique window into the possible formation mechanism of more massive, isolated galaxies.

Be careful, Lawyer Herald will lock up your web browser!

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Axion Astronomy for New Microwave Haloscopes Simulated

by Tommy on 19/01/2017

Now that I know that the gravitational axion will soon be detected, next up is axion astronomy.

Of course, very course grained optical axion astronomy is already being routinely performed.

https://arxiv.org/abs/1701.03118

Axion astronomy with microwave cavity experiments, Ciaran A. J. O’Hare and Anne M. Green (11 January 2017)

Terrestrial searches for the conversion of dark matter axions or axion-like particles into photons inside magnetic fields are sensitive to the phase space structure of the local Milky Way halo. We simulate signals in a hypothetical future experiment based on the Axion Dark Matter eXperiment (ADMX) that could be performed once the axion has been detected and a frequency range containing the axion mass has been identified. We develop a statistical analysis to extract astrophysical parameters, such as the halo velocity dispersion and laboratory velocity, from such data and find that with only a few days integration time a level of precision can be reached matching that of astronomical observations. For longer experiments lasting up to a year in duration we find that exploiting the modulation of the power spectrum in time allows accurate measurements of the Solar peculiar velocity with an accuracy that would improve upon astronomical observations. We also simulate signals based on results from N-body simulations and find that finer substructure in the form of tidal streams would show up prominently in future data, even if only a subdominant contribution to the local dark matter distribution. In these cases it would be possible to reconstruct all the properties of a dark matter stream using the time and frequency dependence of the signal. Finally we consider the detection prospects for a network of streams from tidally disrupted axion miniclusters. These features appear much more prominently in the resolved spectrum than suggested by calculations based on a scan over a range of resonant frequencies, making the detection of axion minicluster streams more viable than previously thought. These results confirm that haloscope experiments in a post-discovery era are able to perform “axion astronomy”.

This article also contains a concise mathematical exposition of axion to photon conversion.

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The Reduced Charge Transfer Gap in the Multilayer Cuprates

by Tommy on 18/01/2017

This straightforward analysis solves the multilayer problem of the cuprates.

https://arxiv.org/abs/1701.04190

Relationship between the parent charge transfer gap and maximum transition temperature in cuprates, Wei Ruan, Cheng Hu, Jianfa Zhao, Peng Cai, Yingying Peng, Cun Ye, Runze Yu, Xintong Li, Zhenqi Hao, Changqing Jin, Xingjiang Zhou, Zheng-Yu Weng and Yayu Wang (17 January 2017)

One of the biggest puzzles concerning the cuprate high temperature superconductors is what determines the maximum transition temperature (Tc,max), which varies from less than 30 K to above 130 K in different compounds. Despite this dramatic variation, a robust trend is that within each family, the double-layer compound always has higher Tc,max than the single-layer counterpart. Here we use scanning tunneling microscopy to investigate the electronic structure of four cuprate parent compounds belonging to two different families. We find that within each family, the double layer compound has a much smaller charge transfer gap size (ΔCT), indicating a clear anticorrelation between ΔCT and Tc,max. These results suggest that the charge transfer gap plays a key role in the superconducting physics of cuprates, which shed important new light on the high Tc mechanism from doped Mott insulator perspective.

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Anomalous Transport with Non-Abelian Berry Curvature

by Tommy on 18/01/2017

This generalization is proving to be quite useful.

https://arxiv.org/abs/1701.04012

Kinetic Theory and Anomalous Transports in the Presence of Nonabelian Phase-Space Berry Curvatures, Tomoya Hayata and Yoshimasa Hidaka (15 January 2017)

We construct the kinetic theory in (1+2d)-dimensional phase space and time when all abelian and nonabelian phase-space Berry curvatures are nonzero. Then we calculate anomalous transports induced by the Berry curvatures on the basis of the kinetic theory. As an example, we study anomalous charge and spin transports induced by the SU(2) Berry curvatures. We also derive the topological effective theory to reproduce the transports in insulators calculated from the kinetic theory. Such an effective theory is given by the nonabelian phase space Chern-Simons theory.

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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.

No Comments

Donald Trump and Jeff Sessions Illegitimate Russian Operatives

by Tommy on 16/01/2017
Donald Trump Illegitimate President Jeff Sessions Illegitimate Attorney General

Donald Trump Illegitimate President Jeff Sessions Illegitimate Attorney General

I will not accept Donald Trump as the President of the United States of America.

I will not accept Jeff Sessions as the Attorney General of the United States of America.

Donald Trump and Jeff Sessions – Illegitimate Russian Operatives – Vladimir Putin Stooges.

I will resist Donald Trump, Jeff Sessions and their Cabinet and Staff as an American Citizen.

I will not assist them, I will resist them. I refuse to cooperate with them, and I will fight them.

https://www.nytimes.com/2017/01/16/opinion/johns-gospel-of-trumps-illegitimacy.html

https://www.nytimes.com/2017/01/16/opinion/with-all-due-disrespect.html

I disrespect and reject Donald Trump and Jeff Sessions.

Completely and absolutely.

Irreversibly.

Forever.

Update: I am a Leader of the American Resistance Movement.

My name is Thomas Lee Elifritz. I am an American. I am a Scientist. I am a Progressive.

And I am a Citizen of the United States of America.

Don’t Tread on my Nation and my Planet.

Progressive Logo

Progressive Logo

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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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Neural Spasmology is a Subdomain of Quantum Cosmology

by Tommy on 7/01/2017

I had to look that one up too. I’m gonna need a spasmologist, and a good spasmometer.

With a cool retro 60’s meter. Something from a 50’s sci fi movie.

I prefer to think of it as incoherent.

Or possibly even chaotic.

I’ll sort it out.

Eventually.

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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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Happy New Year Hollyweed, California, USA

by Tommy on 1/01/2017
Hollyweed California USA

Hollyweed California USA

In 2017, when they go low, we’ll go high.

Fuck you, Jeff Sessions.

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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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Vera Rubin – The Astronomer Who Discovered Dark Matter

by Tommy on 26/12/2016

My plan to bring her the Nobel Prize she had earned has now failed.

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

I’ll write it and publish it anyways.

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

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Minkowski Space is a Perfect Quantum Superfluid

by Tommy on 24/12/2016

Extremely strong, nearly massless, and a superfluid in some cases.

Motion is dissipationless, unless you are two particles revolving around each other.

I’m brainstorming here apriori and in stream of consciousness, since I’m in the middle of writing my dark matter axion paper and so I need to develop a suitably dramatic plot with some kind of heroic ending that returns me to the beginning and solves my own tragic personal conundrum.

So yeah, Minkoski space is flat. So how do you even know you’re moving? Oh, it takes energy and a force to create momentum. So it would take energy to inflate the Minkowski space too.

And indeed you won’t know you’re moving, absent any action, and it would take another particle with a different momentum to even know that, and of course you need a means to measure momentum. With differing momenta then you have spacetime gravitation and curvature suddenly. So particles cause the curvature of space. Mass. So upon this perfectly cold quantum superfluid vacuum of space at absolute zero, absent particles and excitations of the field (gravity waves), there must be another excited layer of spacetime that represents curvature that was lost when the enormous energy of flat Minkowski space inflation occurred, which basically completely flattened out quantum spacetime, except for the mass contained within it, before that mass spontaneously appeared. That’s the dark matter, the so called ‘gravitational axions’. You could call them curvatons I guess. So the real problem is where does the axion ground state lie, how far about the gravitational vacuum does it lie, and is it a superfluid. Right now I’m leaning towards it being the quasiparticle excitation spectrum of the superfluid vacuum, and I’m not opposed to some or even the majority of those excitations being collective and ‘coherent’.

The quantum spacetime pseudogap.

Or not.

Update: The first part of the essay is finished except for the editing and changes.

It was starting to run off the rails into woo at the end, so I have to switch to quantum field theory.

And the actual experimental observational astronomical evidence.

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

Gravitational Axions as Dark Matter

Update 2: I really had to hack it up, too much holiday cheer.

The quantum cosmology crap will have to wait for another essay.

I just want to understand and detect the freakin axion.

Update 3: http://lifeform.net/archimedes/Quantum_Cosmology.pdf

Gravitational Axions in Quantum Gravity and Cosmology

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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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