What We Know About OSIRIS-REx Asteroid (101955) Bennu

by Tommy on 25/11/2015
Asteroid 101955 Bennu

Asteroid 101955 Bennu


The Design Reference Asteroid for the OSIRIS-REx Mission Target (101955) Bennu, Carl W. Hergenrother, Maria Antonietta Barucci, Olivier Barnouin, Beau Bierhaus, Richard P. Binzel, William F. Bottke, Steve Chesley, Ben C. Clark, Beth E. Clark, Ed Cloutis, Christian Drouet d’Aubigny, Marco Delbo, Josh Emery, Bob Gaskell, Ellen Howell, Lindsay Keller, Michael Kelley, John Marshall, Patrick Michel, Michael Nolan, Bashar Rizk, Dan Scheeres, Driss Takir, David D. Vokrouhlický, Ed Beshore and Dante S. Lauretta, (16 September 2014)

The Design Reference Asteroid (DRA) is a compilation of all that is known about the OSIRIS-REx mission target, asteroid (101955) Bennu. It contains our best knowledge of the properties of Bennu based on an extensive observational campaign that began shortly after its discovery, and has been used to inform mission plan development and flight system design. The DRA will also be compared with post-encounter science results to determine the accuracy of our Earth-based characterization efforts. The extensive observations of Bennu in 1999 has made it one of the best-characterized near-Earth asteroids. Many physical parameters are well determined, and span a number of categories: Orbital, Bulk, Rotational, Radar, Photometric, Spectroscopic, Thermal, Surface Analog, and Environment Properties. Some results described in the DRA have been published in peer-reviewed journals while others have been reviewed by OSIRIS-REx Science Team members and/or external reviewers. Some data, such as Surface Analog Properties, are based on our best knowledge of asteroid surfaces, in particular those of asteroids Eros and Itokawa. This public release of the OSIRIS-REx Design Reference Asteroid is a annotated version of the internal OSIRIS-REx document OREX-DOCS-04.00-00002, Rev 9 (accepted by the OSIRIS-REx project on 2014-April-14). The supplemental data products that accompany the official OSIRIS-REx version of the DRA are not included in this release. We are making this document available as a service to future mission planners in the hope that it will inform their efforts.

The more I think about it, Bennu has the greatest possibilities.

It’s big, it’s somewhat close, if being on the other side of the sun for years can be close, it’s not particularly stony, whatever it is, and it will be the best known asteroid when they’re done with it.

Thunderbirds are go!

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Cross-Correlated Responses of Topological Superconductors and Superfluids

by Tommy on 24/11/2015


Cross-Correlated Responses of Topological Superconductors and Superfluids, Kentaro Nomura, Shinsei Ryu, Akira Furusaki and Naoto Nagaosa, Phys. Rev. Lett. 108, 026802 (12 January 2012), DOI:10.1103/PhysRevLett.108.026802

We study nontrivial responses of topological superconductors and superfluids to the temperature gradient and rotation of the system. In two-dimensional gapped systems, the Strěda formula for the electric Hall conductivity is generalized to the thermal Hall conductivity. Applying this formula to the Majorana surface states of three-dimensional topological superconductors predicts cross-correlated responses between the orbital angular momentum and thermal polarization (entropy polarization). These results can be naturally related to the gravitoelectromagnetism description of three-dimensional topological superconductors and superfluids, analogous to the topological magnetoelectric effect in Z2 topological insulators.

See also: http://journals.aps.org/prb/abstract/10.1103/PhysRevB.78.195424

Topological field theory of time-reversal invariant insulators, Xiao-Liang Qi, Taylor L. Hughes and Shou-Cheng Zhang, Phys. Rev. B 78, 195424 (24 November 2008), DOI:10.1103/PhysRevB.78.195424

Download PDF

We show that the fundamental time-reversal invariant (TRI) insulator exists in 4+1 dimensions, where the effective-field theory is described by the (4+1)- dimensional Chern-Simons theory and the topological properties of the electronic structure are classified by the second Chern number. These topological properties are the natural generalizations of the time reversal-breaking quantum Hall insulator in 2+1 dimensions. The TRI quantum spin Hall insulator in 2+1 dimensions and the topological insulator in 3+1 dimensions can be obtained as descendants from the fundamental TRI insulator in 4+1 dimensions through a dimensional reduction procedure. The effective topological field theory and the Z2 topological classification for the TRI insulators in 2+1 and 3+1 dimensions are naturally obtained from this procedure. All physically measurable topological response functions of the TRI insulators are completely described by the effective topological field theory. Our effective topological field theory predicts a number of measurable phenomena, the most striking of which is the topological magnetoelectric effect, where an electric field generates a topological contribution to the magnetization in the same direction, with a universal constant of proportionality quantized in odd multiples of the fine-structure constant α = e2/ℏc. Finally, we present a general classification of all topological insulators in various dimensions and describe them in terms of a unified topological Chern-Simons field theory in phase space.

See also this Review: http://physics.aps.org/articles/v1/36

Viewpoint: High-energy physics in a new guise, Marcel Franz, APS Physics 1, 36 (24 November 2008)

The esoteric concept of “axions” was born thirty years ago as an attempt to resolve a puzzle in the description of the strong interaction between quarks. It appears that the same physics — though in a much different context — applies to an unusual class of insulators.

In these presentations the math is much more accessible.

Seven years ago today. 100 years ago tomorrow

Axions – Whoever heard of such a thing!

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Nuclear Isotope Proxies Reveal Oxygenation of Atmosphere

by Tommy on 24/11/2015


Transient episodes of mild environmental oxygenation and oxidative continental weathering during the late Archean, Brian Kendall, Robert A. Creaser, Christopher T. Reinhard, Timothy W. Lyons and Ariel D. Anbar, Science Advances, Vol. 1, No. 10, e1500777 (20 November 2015), DOI:10.1126/sciadv.1500777

It is not known whether environmental O2 levels increased in a linear fashion or fluctuated dynamically between the evolution of oxygenic photosynthesis and the later Great Oxidation Event. New rhenium-osmium isotope data from the late Archean Mount McRae Shale, Western Australia, reveal a transient episode of oxidative continental weathering more than 50 million years before the onset of the Great Oxidation Event. A depositional age of 2495 ± 14 million years and an initial 187Os/188Os of 0.34 ± 0.19 were obtained for rhenium- and molybdenum-rich black shales. The initial 187Os/188Os is higher than the mantle/extraterrestrial value of 0.11, pointing to mild environmental oxygenation and oxidative mobilization of rhenium, molybdenum, and radiogenic osmium from the upper continental crust and to contemporaneous transport of these metals to seawater. By contrast, stratigraphically overlying black shales are rhenium- and molybdenum-poor and have a mantle-like initial 187Os/188Os of 0.06 ± 0.09, indicating a reduced continental flux of rhenium, molybdenum, and osmium to seawater because of a drop in environmental O2 levels. Transient oxygenation events, like the one captured by the Mount McRae Shale, probably separated intervals of less oxygenated conditions during the late Archean.

Very nice. Behold the slime era!

Soon there will be blobs.

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Blue Origin Jeff Bezos Hydrogen Reusable Launch Vehicle Test

by Tommy on 22/11/2015
Jeff Bezos - Blue Origin - BE-3 - First Flight

Jeff Bezos – Blue Origin – BE-3 – First Flight

Soon. Today or Tomorrow.

Stay tuned for updates.

Update: 329,839 feet. 100.5 kilometers.

Blue Origin New Shepard Used Launch Vehicle

Blue Origin New Shepard Used Launch Vehicle

Free on the curb. Must take all.

Update 2: Space geeks, space nerds and space cadets are having a field day with this one.

Hopefully Elon Musk and his team at SpaceX will have a successful return to flight real soon.

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Supersymmetric Dark Matter WIMPs Now Poised to be Refuted

by Tommy on 20/11/2015
Gran Sasso National Laboratory Xenon1T WIMP Detector

Gran Sasso National Laboratory Xenon1T WIMP Detector


Largest ever dark-matter experiment poised to test popular theory, XENON1T could make history – or spell the end for ‘supersymmetric’ dark matter, Edwin Cartlidge, Nature (16 November 2015), doi:10.1038/nature.2015.18772

That is one fine looking gonkulator they have there.

Axions are the next big thing.

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Ab Initio Calculation of Most Probable N-Diamond Structure

by Tommy on 19/11/2015

Here is something I missed.


Ab initio structure determination of n-diamond, Da Li, Fubo Tian, Binhua Chu, Defang Duan, Xiaojing Sha, Yunzhou Lv, Huadi Zhang, Nan Lu, Bingbing Liu and Tian Cui, Scientific Reports 5, 13447 (24 August 2015), doi:10.1038/srep13447

A systematic computational study on the crystal structure of n-diamond has been performed using first-principle methods. A novel carbon allotrope with hexagonal symmetry R32 space group has been predicted. We name it as HR-carbon. HR-carbon composed of lonsdaleite layers and unique C3 isosceles triangle rings, is stable over graphite phase above 14.2 GPa. The simulated x-ray diffraction pattern, Raman, and energy-loss near-edge spectrum can match the experimental results very well, indicating that HR-carbon is a likely candidate structure for n-diamond. HR-carbon has an incompressible atomic arrangement because of unique C3 isosceles triangle rings. The hardness and bulk modulus of HR-carbon are calculated to be 80 GPa and 427 GPa, respectively, which are comparable to those of diamond. C3 isosceles triangle rings are very important for the stability and hardness of HR-carbon.

Every thing you know is wrong.

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Amalgamated Minerals Praises US Space Mining Legislation

by Tommy on 18/11/2015

November 18, 2015

Press Release. News Release. Released For Immediate Publication.

Hugh Mann, president and CEO of Amalgamated Minerals LLC of Deimos, Mars, praises the recent passage of H.R. 1508, the Space Resource Exploration and Utilization Act of 2015, and H. R. 2262, the U.S. Commercial Space Launch Competitiveness Act, and wishes for a speedy presidential signature on that insignificant scrap of paper, hopefully before the giant asteroid hits the Earth and destroys humanity. Fortunately the president will soon save us from bankruptcy.

“We just can’t have any loose ends up here, life is tough enough already”, stated Hugh Mann.






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Structure and Superconductivity of Bismuth Hydrides Studied

by Tommy on 18/11/2015

Ok, get ready, here it comes!


High-pressure structures and superconductivity of bismuth hydrides, Yanbin Ma, Defang Duan, Da Li, Yunxian Liu, Fubo Tian, Hongyu Yu, Chunhong Xu, Ziji Shao, Bingbing Liu and Tian Cui
(17 November 2015)

We have systematically searched for the ground state structures of bismuth hydrides based on evolutionary algorithm method and particle swarm optimization algorithm method. Given only rich-hydrogen region, except for BiH3, other hydrides (BiH, BiH2, BiH4, BiH5, BiH6) have been predicted to be stable with pressurization. With the increase of hydrogen content, hydrogen exists in bismuth hydrides with the different forms and presents the characteristics of ionicity. Under high pressure, the remarkable structural feature is the emergence of H2 units in BiH2, BiH4 and BiH6, and BiH6 adopts a startling layered structure intercalated by H2 and the linear H3 units. Further calculations show these energetically stable hydrides are good metal and their metallic pressures are lower than that of pure solid hydrogen because of the doping impurities. The Tc in the range of 20-119 K has been calculated by the Allen-Dynes modified McMillan equation, which indicates all these stable hydrides are potential high-temperature superconductors. Remarkably, it is the H-Bi-H and Bi atoms vibrations rather than the high-frequency H2 or H3 units that dominate the superconductivity. In addition, hydrogen content has a great influence on the superconducting transition temperature.

Now muck it up with some iodine.

This is gonna be great fun.

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Human Space Missions to the Fifth Planet Ceres Planned

by Tommy on 17/11/2015
Ceres Dawn Crater Bright Spots Mountain Channels

Ceres Dawn Crater Bright Spots Mountain Channels

Led by Lou Friedman, The Planetary Society, and the Iranians, of course.

A final mission destination scenario is developed and presented for my space colonization architecture, using ground truth from the high and mid level mapping of Ceres, and as a direct challenge to a recent Planetary Society essay by Louis Friedman where he claims colonization of deep space is impossible.

Ceres is a massive planetoid in the center of the asteroid belt between Mars and Jupiter, and possesses the fourth largest surface gravitational attraction moderately acceptable for human habitation, after the Earth, Mars and the Moon. With a solar irradiance of only 1/10th that of the Earth, it is most likely the final practicable location for permanent human space colonization within the entire inner solar system.

Ceres is a water abundant ice world, due to the circumstances of gas giant planetary migration in the early evolution of the solar system, possessing a frozen deep ocean lying just below its dry, disordered surface crust and regolith. It appears that in many areas water vapor cryovolcanism and crustal eruption has occurred in the past, leaving bright deposits of salts and minerals observed widely across the body. The surface soils of Ceres appears to consist of widespread ammoniated and hydrated phyllosilicates, and other various clay like minerals, interspersed and contaminated with a variety of impact materials.


Missions to the Fifth Planet Ceres

More low hanging fruit.

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The Latest and Greatest Thinking on the Cosmic QCD Axions

by Tommy on 16/11/2015

They Might Be Giants

Relatively speaking, that is.


Lattice QCD and Axion Cosmology, Evan Berkowitz, Proceedings for the 33rd International Symposium on Lattice Field Theory, 14 -18 July 2015, Kobe International Conference Center, Kobe, Japan (9 September 2015)

The Strong CP Problem can be resolved by introducing an additional global symmetry known as Peccei-Quinn symmetry. Once PQ symmetry is broken the associated particle, the QCD axion, is a plausible dark matter candidate. Calculating the cosmological energy density of the axion requires nonperturbative QCD input – the high-temperature topological susceptibility. I will show results from a pure-glue calculation and examine the implications for the axion mass and coupling.

See also: http://arxiv.org/abs/1511.02867

The QCD axion, precisely, Giovanni Grilli di Cortona, Edward Hardy, Javier Pardo Vega and Giovanni Villadoro (9 November 2015)

We show how several properties of the QCD axion can be extracted at high precision using only first principle QCD computations. By combining NLO results obtained in chiral perturbation theory with recent Lattice QCD results the full axion potential, its mass and the coupling to photons can be reconstructed with percent precision. Axion couplings to nucleons can also be derived reliably, with uncertainties smaller than ten percent. The approach presented here allows the precision to be further improved as uncertainties on the light quark masses and the effective theory couplings are reduced. We also compute the finite temperature dependence of the axion potential and its mass up to the crossover region. For higher temperature we point out the unreliability of the conventional instanton approach and study its impact on the computation of the axion relic abundance.

0.1 meV is a pretty heavy axion, as far as axions go.

Wanna scrunch some leaves?

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The Higgs Mechanism in Axionic Topological Superconductors

by Tommy on 15/11/2015


Higgs Mechanism and Anomalous Hall Effect in Three-Dimensional Topological Superconductors, Flavio S. Nogueira, Asle Sudbø and Ilya Eremin (29 April 2015)

We demonstrate that the Higgs mechanism in three-dimensional topological superconductors exhibits unique features with experimentally observable consequences. The Higgs model we discuss has two superconducting components and an axion-like magnetoelectric term with the phase difference of the superconducting order parameters playing the role of the axion field. Due to this additional term, quantum electromagnetic and phase fluctuations lead to a robust topologically non-trivial state that cannot be continuously deformed into a topologically non-trivial one. In the low frequency London regime an anomalous Hall effect is induced in the presence of an applied electric field parallel to the surface. This anomalous Hall current is induced by a Lorentz-like force arising from the axion term, and it involves the relative superfluid velocity of the superconducting components. The anomalous Hall current has a negative sign, a situation reminiscent, but quite distinct in physical origin, of the anomalous Hall effect observed in high-Tc superconductors.

I’ve always been a fan of Dr. Sudbø. Ever since I tried to compress a two hour Lizard Lounge science night presentation of my work to some weird biologists, geologists and geophysicists, into a ten minute international conference talk. Dr. Sudbø was the only one who got BCS-BEC.

All I learned was how not to give a science infomercial.

Behold the axion era!

Update: This arXiv paper has been updated.

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A Brief Review of Axionic Superconductivity

by Tommy on 15/11/2015


Axionic superconductivity in three dimensional doped narrow gap semiconductors, Pallab Goswami and Bitan Roy, Phys. Rev. B 90, 041301(R) ( 2014), DOI:10.1103/PhysRevB.90.041301

We consider the competition between the conventional s-wave and the triplet Balian-Werthamer or the B-phase pairings in the doped three dimensional narrow gap semiconductors, such as CuxBi2Se3 and Sn1−xInxTe. When the coupling constants of the two contending channels are comparable, we find a simultaneously time-reversal and parity violating p+is state at low temperatures, which provides an example of dynamic axionic state of matter. In contradistinction to the time-reversal invariant, topological B-phase, the p+is state possesses gapped Majorana fermions as the surface Andreev bound states, which give rise to an anomalous surface thermal Hall effect. The anomalous gravitational and electrodynamic responses of the p+is state can be described by the θ vacuum structure, where θ ≠ 0 or π.

See also: http://arxiv.org/abs/1510.07266

Resonance-state-induced superconductivity at high Indium contents in In-doped SnTe, Neel Haldolaarachchige, Quinn Gibson, Weiwei Xie, Morten Bormann Nielsen, Satya Kushwaha and R. J. Cava

We report a reinvestigation of superconducting Sn1−xInxTe at both low and high In doping levels. Analysis of the superconductivity reveals a fundamental change as a function of x: the system evolves from a weakly coupled to a strongly coupled superconductor with increasing indium content. Hall Effect measurements further show that the carrier density does not vary linearly with Indium content; indeed at high Indium content, the samples are overall n-type, which is contrary to expectations of the standard picture of In1+ replacing Sn2+ in this material. Density functional theory calculations probing the electronic state of In in SnTe show that it does not act as a trivial hole dopant, but instead forms a distinct, partly filled In 5 s – Te p hybridized state centered around EF, very different from what is seen for other nominal hole dopants such as Na, Ag, and vacant Sn sites. We conclude that superconducting In-doped SnTe therefore cannot be considered as a simple hole doped semiconductor.

If at first you don’t succeed, try try again.

Or something like that.

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Atsuo Shitade at Kyoto – Gravitation, Heat and Momentum

by Tommy on 15/11/2015

Why do I need the (Schwinger) Keldysh formalism?

Because of yet another rising star out of the Kyoto group.

Atsuo Shitade



Heat transport as torsional responses and Keldysh formalism in a curved spacetime, Atsuo Shitade, Prog. Theor. Exp. Phys., 123I01 (10 December 2014), doi:10.1093/ptep/ptu162

We revisit a theory of heat transport in the light of a gauge theory of gravity and find the proper heat current with a corresponding gauge field, which yields the natural definitions of the heat magnetization and the Kubo-formula contribution to the thermal conductivity as torsional responses. We also develop a general framework for calculating gravitational responses by combining the Keldysh and Cartan formalisms. By using this framework, we explicitly calculate these two quantities and reproduce the Wiedemann–Franz law for the thermal Hall conductivity in the clean and non-interacting case. Finally, we discuss an effective action for the quantized thermal Hall effect in (2+1)-D topological superconductors.

See also: http://arxiv.org/abs/1312.3448


Theory of Charge and Heat Polarizations with the Keldysh Formalism, Atsuo Shitade, J. Phys. Soc. Jpn. 83, 033708 ( 25 February 2014), DOI:10.7566/JPSJ.83.033708

We investigate the heat polarization, a heat analog of the charge polarization, by using the gauge-covariant Keldysh formalism. In contrast to the charge-heat analogy naively expected, we find that the heat polarization does not appear spontaneously, since it consists not only of the heat-transfer contribution but of the heat-generation contribution, leading to the Mott rule. Nonetheless, it can be induced by a torsional magnetic field in (3 + 1)-D topological insulators and superconductors, which is described by the temporal part of the Nieh–Yan action.

I’m feeling distinctly Einsteinish with this.

The math is … torturous.

To say the least.

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All Mathematics is Physics and All Physics is Mathematics

by Tommy on 12/11/2015

Oh, and one more thing, said Professor Clodumbo.


Quantum mechanical derivation of the Wallis formula for π, Tamar Friedmann and C. R. Hagen, J. Math. Phys. 56, 112101 (2015), DOI:10.1063/1.4930800

A famous pre-Newtonian formula for π is obtained directly from the variational approach to the spectrum of the hydrogen atom in spaces of arbitrary dimensions greater than one, including the physical three dimensions.

Quantum mechanics is suddenly a hot topic, even Forbes is covering it.

Remember that when researching Category Theory.

Up next – The Keldysh Formalism.

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Edward Witten Topological Field Theory and Order on the ArXiv

by Tommy on 9/11/2015
WMAP CMB Universe Timeline Standard Model

WMAP CMB Universe Timeline Standard Model

I haven’t read a high energy physics or cosmology paper in years, having sworn it off way back in the early QCD days of the particle zoo. In fact, I wasn’t even a big fan of the funding of the big machines, and I was thrilled back in the days when the SSC and the SST both got cancelled. And I wish we would get back into the big program cancellation business again, now that I think about it. But I did attend the meetings just to hear the battles. And the Europeans picked up the SLAC over the years and now we are at this inflection point again over this single particle. Or perhaps a zoo of them. The infamous axion and dark matter. DM. I just did another project with the initials DM. Deimos Mission. Deimos, even. I hate these kinds of distractions, they intrude into your nicely categorized and isolated domains and announce their existence, and the next thing you know you are flying off on a tangent ejected from the solar system to roam the cold darkness of deep space for a good long time anyways. Or condensed into a cold superfluid.

So I take some time off from all of my personal relationships and most of my outdoor ‘fall is here winter is coming get your ass in gear work’, and plow through it, muddle through it is a better characterization, until I arrive again at the beginning again, which is, of course, Edward Witten.

And he’s on the ArXiv, as I just noticed. And he just wrote a primer in the November issue of Physics Today. And he has a couple of other recent papers as well. And searching though the cite analytics I am finally led to a wiki entry on topological order which has a nice chronological history and all the references you will ever need on this. I don’t have the time to list them all here because I have to get outside now and prepare for winter. You should know how to find this stuff. Use a search engine to find yourself a search engine. Or go out and pound the pavement. I quit doing that because going into downtown always creates problems and the whole point of this post is that I don’t even need to anymore. Most of it is open and freely available on the intertubz.

And why is this important? Because apparently at first glance quantum topological orders and ordinary superconductivity and superfluidity can be coupled to gravitoelectromagnetism through the dynamical fluctuating axion fields (or axion winds, although you should be able to create your own fluctuating axion fields easily, just wave your arms and hands), IN THE LABORATORY!!!

Note the awesome all caps and the multiple exclamation points. Obviously I’m a genius.

And out of this presumably (eventually, hopefully, maybe) we can produce instant antigravity and unlimited free zero point energy by drawing on deep spacetime string theory and the low entropy early universe. That’s right, this is crackpot heaven, folks. So I’m dropping this like a hot potato and going outside to dig some potatoes. But certainly it’s worth commenting on. So here it is.

Crank up your magnets, ladies and gentlemen. The future has arrived.


Beware of cranks, cracks and potholes.

They’re everywhere.

So crank on!

I’m done.

Update: I’ve dubbed this ‘The Russell Effect’, for Russell Seitz.

Now I’m going to go out and rustle me up some axions.

I’ve already got a rash and blisters from it.

Update 2: Monoidal Categories.

That figures.

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Everything You Ever Wanted To Know About Axion Cosmology

by Tommy on 8/11/2015


Axion Cosmology, David J. E. Marsh (26 October 2015)

Axions comprise a broad class of particles that can play a major role in explaining the unknown aspects of cosmology. They are also extraordinarily well-motivated within high energy physics, and so axion cosmology offers us a unique view onto these theories. I present a comprehensive and pedagogical view on the cosmology and astrophysics of axion-like particles, starting from inflation and progressing via the CMB and structure formation up to the present-day Universe. I briefly review the motivation and models for axions in particle physics and string theory. The primary focus is on the population of ultralight axions created via vacuum realignment, and its role as a dark matter (DM) candidate with distinctive phenomenology. Cosmological observations place robust constraints on the axion mass and relic density in this scenario, and I review where such constraints come from. I next cover aspects of galaxy formation with axion DM, and ways this can be used to further search for evidence of axions. An absolute lower bound on DM particle mass is established. It is ma > 10−24 eV from linear observables, extending to ma ≳ 10−22 eV from non-linear observables, and has the potential to reach ma ≳ 10−18 eV in the future. I then spend some time discussing direct and indirect detection of axions, reviewing existing and future experiments. Miscellaneous additional topics covered include: axions as dark radiation, and axions as dark energy; decays of heavy axions; axions and stellar astrophysics; black hole superradiance; axions and astrophysical magnetic fields; axion inflation, and axion DM as an indirect probe of inflation.

I detect a bit of author bias here, but other than that … enjoy.

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High Pressure Hydrogen Nitrogen Polymer Formation Studied

by Tommy on 8/11/2015


Nitrogen Backbone Oligomers, Hongbo Wang, Mikhail I. Eremets, Ivan Troyan, Hanyu Liu, Yanming Ma and Luc Vereecken, Scientific Reports 5, Article number: 13239 (19 Auguest 2015)

We found that nitrogen and hydrogen directly react at room temperature and pressures of ~35 GPa forming chains of single-bonded nitrogen atom with the rest of the bonds terminated with hydrogen atoms – as identified by IR absorption, Raman, X-ray diffraction experiments and theoretical calculations. At releasing pressures below ~10 GPa, the product transforms into hydrazine. Our findings might open a way for the practical synthesis of these extremely high energetic materials as the formation of nitrogen-hydrogen compounds is favorable already at pressures above 2 GPa according to the calculations.

This is entirely new and novel. You just gotta love these guys.

I can’t wait until they load some liquid bismuthine into their diamond anvil cell.

See also: http://arxiv.org/abs/1511.01879

Sodium Pentazolate: a Nitrogen Rich High Energy Density Material, Brad A. Steele and Ivan I. Oleynik (5 November 2015)

Sodium pentazolates NaN5 and Na2N5, new high energy density materials, are discovered during first principles crystal structure search for the compounds of varying amounts of elemental sodium and nitrogen. The pentazole anion N5 is stabilized in the condensed phase by sodium Na+ cations at pressures exceeding 20 GPa, and becomes metastable upon release of pressure. The sodium azide (NaN3) precursor is predicted to undergo a chemical transformation above 50 GPa into sodium pentazolates NaN5 and Na2N5. The calculated Raman spectrum of NaN5 is in agreement with the experimental Raman spectrum of a previously unidentified substance appearing upon compression and heating of NaN3.

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Refractory Metal Halides – A New Class of Quantum Materials

by Tommy on 8/11/2015


New Family of Quantum Spin Hall Insulators in Two-dimensional Transition-Metal Halide with Large Nontrivial Band Gaps, Liujiang Zhou, Liangzhi Kou, Yan Sun, Claudia Felser, Feiming Hu, Guangcun Shan, Sean C. Smith, Binghai Yan and Thomas Frauenheim (21 October 2015)

Topological insulators (TIs) are promising for achieving dissipationless transport devices due to the robust gapless states inside the insulating bulk gap. However, currently realized 2D TIs, quantum spin Hall (QSH) insulators, suffer from ultra-high vacuum and extremely low temperature. Thus, seeking for desirable QSH insulators with high feasibility of experimental preparation and large nontrivial gap is of great importance for wide applications in spintronics. Based on the first-principles calculations, we predict a novel family of two-dimensional (2D) QSH insulators in transition-metal halide MX (M = Zr, Hf; X = Cl, Br, and I) monolayers with large nontrivial gaps of 0.12−0.4 eV, comparable with bismuth (111) bilayer (0.2 eV), stanene (0.3 eV) and larger than ZrTe5 (0.1 eV) monolayers and graphene-based sandwiched heterstructures (30−70 meV). Their corresponding 3D bulk materials are weak topological insulators from stacking QSH layers, and some of bulk compounds have already been synthesized in experiment. The mechanism for 2D QSH effect in this system originates from a novel d−d band inversion, which is different from conventional band inversion between s−s orbitals, or p−p orbitals. The realization of pure layered MX monolayers may be prepared by exfoliation from their 3D bulk phases, thus holding great promise for nanoscale device applications and stimulating further efforts on transition metal-based QSH materials.

Every day it’s something new.

See also: http://arxiv.org/abs/1406.3173


New Family of Robust 2D Topological Insulators in van der Waals Heterostructures, Liangzhi Kou, Shu-Chun Wu, Claudia Felser, Thomas Frauenheim, Changfeng Chen and Binghai Yan, ACS Nano, 8, 10448 (16 September 2014), DOI:10.1021/nn503789v

We predict a new family of robust two-dimensional (2D) topological insulators in van der Waals heterostructures comprising graphene and chalcogenides BiTeX (X=Cl, Br and I). The layered structures of both constituent materials produce a naturally smooth interface that is conducive to proximity induced new topological states. First principles calculations reveal intrinsic topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be further enhanced up to 120 meV by compression. The strong spin-orbit coupling in BiTeX has a significant influence on the graphene Dirac states, resulting in the topologically nontrivial band structure, which is confirmed by calculated nontrivial Z2 index and an explicit demonstration of metallic edge states. Such heterostructures offer an unique Dirac transport system that combines the 2D Dirac states from graphene and 1D Dirac edge states from the topological insulator, and it offers new ideas for innovative device designs.

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The Topological Axion PhD Thesis of Ken Shiozaki at Kyoto

by Tommy on 8/11/2015



Download PDF

Topological insulators and superconductors: classification of topological crystalline phases and axion phenomena, Ken Shiozaki, PhD Thesis, Kyoto University, Kyoto, Japan (23 March 2015)

This thesis presents two topics of topological insulators and superconductors. One is a classification of topological crystalline insulators and superconductors which are topological phases protected by space group symmetries. Another topic is a study of axion phenomena in topological phases.

See also: http://arxiv.org/abs/1310.4982


Dynamical Axion in Topological Superconductors and Superfluids, Ken Shiozaki and Satoshi Fujimoto, Phys. Rev. B 89, 054506 (14 February 2014), DOI:10.1103/PhysRevB.89.054506

We consider dynamical axion phenomena in topological superconductors and superfluids in three spatial dimensions in terms of the gravitoelectromagnetic topological action, in which the axion field couples with mechanical rotation under finite temperature gradient. The dynamical axion is induced by relative phase fluctuations between topological and s-wave superconducting orders. We show that an antisymmetric spin-orbit interaction which induces parity-mixing of Cooper pairs enlarges the parameter region in which the dynamical axion fluctuation appears as a low-energy excitation. We propose that the dynamical axion increases the moment of inertia, and in the case of ac mechanical rotation, i.e. a shaking motion with a finite frequency ω, as ω approaches the dynamical axion fluctuation mass, the observation of this effect becomes feasible.

It appears now that the detection by coupling to a dynamical axion field is in principle possible.

Axions are, in principle, observable. I think you stir them up with space time fluctuating masses. There are plenty of them around. Wave your arms wildly, you are stirring up some local axions.

Combine that with an electromagnetic field and there you go. Anti-gravity. Energy conversion.

I predict crackpots and crank magnets in the very near future.

See also again: http://arxiv.org/pdf/1006.0690v2.pdf


Topological Defects and Gapless Modes in Insulators and Superconductors, Jeffrey C.Y. Teo and C.L. Kane, Phys. Rev. B82, 115120 (22 September 2010), DOI:10.1103/PhysRevB.82.115120

We develop a unified framework to classify topological defects in insulators and superconductors described by spatially modulated Bloch and Bogoliubov de Gennes Hamiltonians. We consider Hamiltonians H(k,r) that vary slowly with adiabatic parameters r surrounding the defect and belong to any of the ten symmetry classes defined by time reversal symmetry and particle-hole symmetry. The topological classes for such defects are identified, and explicit formulas for the topological invariants are presented. We introduce a generalization of the bulk-boundary correspondence that relates the topological classes to defect Hamiltonians to the presence of protected gapless modes at the defect. Many examples of line and point defects in three dimensional systems will be discussed. These can host one dimensional chiral Dirac fermions, helical Dirac fermions, chiral Majorana fermions and helical Majorana fermions, as well as zero dimensional chiral and Majorana zero modes. This approach can also be used to classify temporal pumping cycles, such as the Thouless charge pump, as well as a fermion parity pump, which is related to the Ising non-Abelian statistics of defects that support Majorana zero modes.

That should keep you busy. K-Theory. You just never know about math.

Update: Monoidal Categories! Who knew.


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3D Magnetic Field Dependent Charge Density Wave (CDW) Found in the Cuprates

by Tommy on 7/11/2015


Three-dimensional charge density wave order in YBa2Cu3O6.67 at high magnetic fields, S. Gerber, H. Jang, H. Nojiri, S. Matsuzawa, H. Yasumura, D. A. Bonn, R. Liang, W. N. Hardy, Z. Islam, A. Mehta, S. Song, M. Sikorski, D. Stefanescu, Y. Feng, S. A. Kivelson, T. P. Devereaux, Z.-X. Shen, C.-C. Kao, W.-S. Lee, D. Zhu, and J.-S. Lee, Science (5 November 2015), DOI:10.1126/science.aac6257

Charge density wave (CDW) correlations have been shown to universally exist in cuprate superconductors. However, their nature at high fields inferred from nuclear magnetic resonance is distinct from that measured by x-ray scattering at zero and low fields. Here we combine a pulsed magnet with an x-ray free electron laser to characterize the CDW in YBa2Cu3O6.67 via x-ray scattering in fields up to 28 Tesla. While the zero-field CDW order, which develops below T ~ 150 K, is essentially two-dimensional, at lower temperature and beyond 15 Tesla, another three-dimensionally ordered CDW emerges. The field-induced CDW appears around the zero-field superconducting transition temperature; in contrast, the incommensurate in-plane ordering vector is field-independent. This implies that the two forms of CDW and high-temperature superconductivity are intimately linked.

This paper is already getting a lot of press from its press release. I don’t quite understand how they have arrived at their conclusions, since I have not yet read the paper, but it’s nice to see the use of the free electron laser in there.

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High Resolution Radar Images of Comet Asteroid 2015 TB145

by Tommy on 4/11/2015
Cometary Asteroid 2015 TB 145

Cometary Asteroid 2015 TB 145

Thunderbirds Are Go!

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Pseudo Gap Phase is the Parent of the Charge Density Wave

by Tommy on 3/11/2015
Cuprate Pseudo Gap Charge Density Wave

Cuprate Pseudo Gap Charge Density Wave

Brookhaven National Laboratory Press Release


Atomic-scale electronic structure of the cuprate d-symmetry form factor density wave state, M. H. Hamidian, S. D. Edkins, Chung Koo Kim, J. C. Davis, A. P. Mackenzie, H. Eisaki, S. Uchida, M. J. Lawler, E.-A. Kim, S. Sachdev and K. Fujita, Nature Physics (26 October 2015), doi:10.1038/nphys3519

Research on high-temperature superconducting cuprates is at present focused on identifying the relationship between the classic ‘pseudogap’ phenomenon and the more recently investigated density wave state. This state is generally characterized by a wavevector Q parallel to the planar Cu–O–Cu bonds along with a predominantly d-symmetry form factor (dFF-DW). To identify the microscopic mechanism giving rise to this state, one must identify the momentum-space states contributing to the dFF-DW spectral weight, determine their particle–hole phase relationship about the Fermi energy, establish whether they exhibit a characteristic energy gap, and understand the evolution of all these phenomena throughout the phase diagram. Here we use energy-resolved sublattice visualization of electronic structure and reveal that the characteristic energy of the dFF-DW modulations is actually the ‘pseudogap’ energy Δ1. Moreover, we demonstrate that the dFF-DW modulations at E  =  −Δ1 (filled states) occur with relative phase π compared to those at E  =  Δ1 (empty states). Finally, we show that the conventionally defined dFF-DW Q corresponds to scattering between the ‘hot frontier’ regions of momentum-space beyond which Bogoliubov quasiparticles cease to exist. These data indicate that the cuprate dFF-DW state involves particle–hole interactions focused at the pseudogap energy scale and between the four pairs of ‘hot frontier’ regions in momentum space where the pseudogap opens.

Ok. So far so good. Now what?

Excitons, anyone?

Update: Every time I reach a new point like this I think – ‘What would Philip W. Phillips do?’

Personally I think that if quantum critical points are involved the quantum weirdness would show up in the broad mid-infrared band, as we are seeing. What we are seeing are just the simplest possible low energy, low temperature results coming out of all of that quantum self ordering.

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Deimos Mission – Vertical Cylindrical Cased Tunnel Shafts – Excavations for Solar and Cosmic Galactic Radiation Protection

by Tommy on 2/11/2015



Deimos Mission – Vertical Cylindrical Cased Tunnel Shaft Excavations
For Solar and Galactic Cosmic Radiation Protection

In another recent essay, I have described in moderate detail the value and procedures for establishing a continuous human presence on the Martian moons Phobos and Deimos, as complementary precursor efforts for the permanent development and colonization of the surface of the planet Mars. The orbital geometries and masses of the moons are leveraged to produce a quick and easy method of solar energy asset deployment and electrical power distribution across the entire surfaces of both of these moons. In this manner electrical energy may be transmitted from the illuminated areas on the moons, to areas that are not currently illuminated, including under the surfaces and in the interiors of the moons. This essay will expand upon one specific aspect of this Martian Moon development and colonization effort, that of providing the immediate capabilities to excavate and case deep vertical cylindrical mining tunnel shafts directly under a landed Deimos Colonial Transport spacecraft, on the very first mission to these moons. Such a construction can then provide massive and immediate shielding against solar proton events and galactic cosmic radiation, the single most urgent problem confronting large scale space development. The excavating design process and the resulting hardware is universally applicable to asteroid mining.

This will be a couple of pages. You can follow it as I write it, but the work on this is already done.

This will be next year’s NIAC submission I guess.

Deimos Surface Viking 2

Deimos Surface Viking 2

See also: Phobos and Deimos – Living on the Moons of Mars


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Nuclear Proxies for Extreme Solar Proton Storm Events

by Tommy on 2/11/2015

Lund University Press Release


Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4, Florian Mekhaldi, Raimund Muscheler, Florian Adolphi, Ala Aldahan, Jürg Beer, Joseph R. McConnell, Göran Possnert, Michael Sigl, Anders Svensson, Hans-Arno Synal, Kees C. Welten and Thomas E. Woodruff, Nature Communications, 6, 8611 (26 October 2015), doi:10.1038/ncomms9611

The origin of two large peaks in the atmospheric radiocarbon (14C) concentration at AD 774/5 and 993/4 is still debated. There is consensus, however, that these features can only be explained by an increase in the atmospheric 14C production rate due to an extraterrestrial event. Here we provide evidence that these peaks were most likely produced by extreme solar events, based on several new annually resolved 10Be measurements from both Arctic and Antarctic ice cores. Using ice core 36Cl data in pair with 10Be, we further show that these solar events were characterized by a very hard energy spectrum with high fluxes of solar protons with energy above 100 MeV. These results imply that the larger of the two events (AD 774/5) was at least five times stronger than any instrumentally recorded solar event. Our findings highlight the importance of studying the possibility of severe solar energetic particle events.

It’s not looking too good for the primate’s electrical spark wire network.

The White House needs to get right on this problem!

Update: The grid would have to be shut down

Think giant ice storm with no damage.

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Surface Grooves on Phobos are Evidence of Disintegration

by Tommy on 31/10/2015
Phobos HiRISE MRO Mars

Phobos HiRISE MRO Mars


Surface Evolution from Orbital Decay on Phobos and Triton, Terry Hurford, Erik Asphaug, Joseph Spitale, Douglas Hemingway, Alyssa Rhoden, Wade Henning, Bruce Bills, Simon Kattenhorn and Matthew Walker, Paper No. 340-1, Presentation Time: 1:30 PM, 2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Phobos, the innermost satellite of Mars, displays an extensive system of grooves that are mostly symmetric about its sub-Mars point. Phobos is steadily spiraling inward due to the tides it raises, and will suffer tidal disruption before colliding with Mars. We calculate the surface stress field of the de-orbiting satellite and show that the first signs of tidal disruption are already present on its surface. Most of Phobos’ prominent grooves have an excellent correlation with computed stress orientations. The model predicts an interior that has very low strength on the tidal evolution timescale, overlain by a ~10-100 m exterior shell that has elastic properties similar to lunar regolith.

Shortly after the Viking spacecraft obtained the first geomorphic images of Phobos, it was proposed that stresses from orbital decay cause grooves. But, assuming a homogeneous Phobos, it proved impossible to account for the build-up of failure stress in the exterior regardless of the value assumed for Phobos’ rigidity. Hence, the tidal model languished. Here, we revisit the tidal origin of surface fractures with a more detailed treatment that shows the production of significant stress in a surface layer, with a very strong correlation to the geometry of grooves.

Our model results applied to surface observations imply that Phobos has a rubble pile interior that is nearly strengthless. A lunar-like cohesive regolith outer layer overlays the rubble pile interior. This outer layer behaves elastically and can experience significant tidal stress at levels able to drive tensile failure. Fissures can develop as the global body deforms due to increasing tides related to orbital decay. Phobos may have an active and evolving surface; an exciting target for further exploration. The interior predictions of this model can be evaluated by future detailed studies performed by an orbiter or lander.

New Scientist Article

A sudden appearance of a large debris ring around Mars would not be helpful for any Mars surface development and colonization effort. Much like a large abrupt sea level rise from the disintegration of West Antarctica would not be helpful for Earth people living near the sea.

Phobos and Deimos – Living on the Moons of Mars


Be very afraid. Deimos it is, then.

Update: To prevent this guaranteed future planetary ring disaster at Mars, we will obviously have to tunnel through the regolith layer into the disordered rubble pile interior of Phobos, and extract the entire body of material and transport it beyond the Roche limit of the planet Mars.

Or alternatively, to Deimos. In other words, we will need to construct an entirely new moon of Mars out of the material available in Phobos, or simply transport all of the material to Deimos.

Think of it as a long term Martian planetary protection program, directly applicable to asteroids.

Speaking of planetary protection, I am seriously thinking of self nominating myself for any open planetary protection sub-committee member position on the NASA Advisory Council’s science committees, since apparently I am now the defacto world leader in this field. I’m sure that will go over like a ton of wet Phobos regolith leaking out of a giant bag onto the conference room table.

Or, alternatively, you can nominate me yourself if you are following what I am saying about this.

The deadline for sub-committee nominations is November 23rd, 2015.

NASA Advisory Council’s Science Committee Subcommittees.


NASA announces its annual invitation for public nominations for service on the NASA Advisory Council’s Science Committee subcommittees. Five science subcommittees report to the Science Committee of the NASA Advisory Council (NAC), a Federal advisory committee under the Federal Advisory Committee Act (FACA). U.S. citizens may submit self-nominations for consideration to fill intermittent vacancies on these five science subcommittees. NASA’s science subcommittees have member vacancies from time to time throughout the year, and NASA will consider self-nominations to fill such intermittent vacancies. Nominees will only be contacted should a vacancy arise and it is judged that their area(s) of expertise is appropriate for that specific vacancy. NASA is committed to selecting members to serve on its science subcommittees based on their individual expertise, knowledge, experience, and current/past contributions to the relevant subject area.

Planetary Protection Subcommittee is a standing subcommittee of the NAC Science Committee supporting the advisory needs of the NASA Administrator, the Science Mission Directorate (SMD), SMD’s Planetary Science Division (PSD), NASA’s Planetary Protection Officer, and other NASA Mission Directorates as required. The scope of the PPS includes programs, policies, plans, hazard identification and risk assessment, and other matters pertinent to the Agency’s responsibilities for biological planetary protection. This scope includes consideration of NASA planetary protection policy documents, implementation plans, and organization. The subcommittee will review and recommend appropriate planetary protection categorizations for all bodies of the solar system to which spacecraft will be sent. The scope also includes the development of near-term enabling technologies, systems, and capabilities, as well as developments with the potential to provide long-term improvements in future operational systems to support planetary protection. Outside the scope of the Subcommittee’s responsibilities are issues that pertain solely to the quality and interpretation of scientific experiments and data in support of solar system exploration.

The deadline for sub-committee nominations is November 23rd, 2015.

Deimos Mission – Vertical Cylindrical Cased Tunnel Shaft Excavations
For Solar and Galactic Cosmic Radiation Protection


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2015 TB145 Halloween Comet Asteroid is 600 Meters Wide

by Tommy on 31/10/2015
2015 TB145 Halloween Comet Asteroid

2015 TB145 Halloween Comet Asteroid

Twice as large as expected. Something like this is could have easily punched a large temporary crater in the ice sheet south of Lake Nipigon. I’m not saying that happened, but … just sayin.

I was surprised that something like this even existed, but it’s fairly obvious there are quite a few of these things out there, and they are being replenished all the time. Wider is not better here.

Evil, pure and simple, by way of the eighth dimension.

At least axions and neutrinos don’t harass us.

Update: This image alone paid for Aricebo.

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Apollo 10 Lunar Module WT1190F Snoopy Comes Home

by Tommy on 30/10/2015
Apollo 10 Lunar Ascent Module Snoopy WT1190F

Apollo 10 Lunar Ascent Module Snoopy WT1190F

Great World War I Flying Ace Snoopy Returns.

Charlie Brown is going to be thrilled.

The Great Pumpkin Abides.

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Blue Origin Jeff Bezos BE-4 Methane Engine Switches to a Vertical Turbopump Shaft

by Tommy on 30/10/2015
Blue Origin Jeff Bezos BE-4 Methane Engine

Blue Origin Jeff Bezos BE-4 Methane Engine

Gravity, Acceleration, Fuel Flow, Turbopump Shaft Bearings, Gaskets, Seals, etc.

That all makes pretty good engineering sense.

I hope Raptor and BE-4 happen soon.

Some RLVs to put them on too.

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Phobos and Deimos – Living on the Moons of Mars

by Tommy on 29/10/2015
Phobos Deimos Mars Moons

Phobos Deimos Mars Moons


Phobos and Deimos – Living on the Moons of Mars.

In a series of recent essays I have sketched out a viable theory of space development and colonization. Within this framework almost any asteroidal or planetary body within the orbit of Mars is suitable for immediate development of its regolith, for spacecraft and habitat shielding, where the smaller cometary derived and volatile rich carbonaceous bodies with enough solar irradiance are suitable for destinations. Volatiles may be extracted from the regolith of these bodies in small amounts by the novel technique of pressurized space encapsulation and optical and solar irradiation, with the residue bagged for shielding. The extremely low gravity of small asteroid bodies makes it quite easy to transfer the asteroid tunneling and mining equipment onto the asteroid, and subsequently transfer the resultant volatile fluids and any asteroid slag off of the surface, but it also had an added disadvantage in that it makes mining operations more hazardous, due to the ease in which processing dust and debris may escape the surface entirely.

Unless the object is small enough (~10 meters) to capture, encapsulate and derotate the body in one swift operation, as described by the Keck asteroid bagging scheme, and then double bagged into mildly pressurized space as indicated by my own Asteroid Redirect Mission proposal, the process of materials extraction from the surface of the asteroid becomes much more problematic since the gravity of small asteroids approaches negligible as their size and mass decreases.

However for larger asteroids, where the acceleration of dust and debris is such that it can be kept below the orbital and escape velocity of the body, processes may be developed where loss of dust and debris can be eliminated completely or greatly reduced, while still retaining the ability to process large boulders on the surface, tunnel into the surface, and deliver equipment to do so, in addition to removal of mined volatile fluids and shielding slag. It is not presently known what the size and mass cutoff is for this particular mining scenario, but it is expected to be in the range of 10 to 15 kilometers or so, where orbital velocities are expected to be measured in meters per second and escape velocities at ~10 meters per second – Phobos and Deimos.

Since there are virtually no objects inside the orbit of Mars of this size, both Phobos and Deimos are the ideal candidates for the testing of these concepts of asteroid mining, tunneling and the manipulation of large boulders on their surfaces. The more promising aspects of Phobos, and particularly Deimos, is that they are both tidally locked to Mars, in roughly the equatorial plane of Mars, and thus they both have well defined seasons at their poles exposing large areas of their surfaces to continuous sunlight over long periods of time, with slow migration of these areas of continuous sunlight over their surfaces.

Obviously then both the surfaces and the poles of Phobos and Deimos are expected to be strategically valuable for any upcoming landing, development and colonization of the surface of the planet Mars. They both provide heavily shielded low gravity refugia above the surface of Mars, where the gravity is large enough to firmly settle large structures onto their surfaces, debris ejection hazards are minimized or eliminated entirely, regolith collection and tunneling operations can be started immediately, sunlight is readily available, and all areas of the surface may be quickly connected by rolling out cable spools across their surface to adjacent areas where continuous sunlight is available, at most tens of kilometers.

Clearly very large and tall structures can be settled onto the surface of Deimos and moved around with relative ease using wheels, treads and tracks. With a surface gravity of 1/3 of one thousandth of a gee, it is conceivable that actual rails could be built where extremely large solar power arrays and space hotels could be transported continuously across the surface near the poles and remain in continuous sunlight. Phobos has a very large planetary occultation factor, but Deimos is ideal for immediate development.

Phobos and Deimos – Living on the Moons of Mars.


As usual, there will be a couple more pages.

ARM to Deimos, that’s the ticket.

Happy Halloween Blobs!

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

Deimos Mission – Vertical Cylindrical Cased Tunnel Shaft Excavations
For Solar and Galactic Cosmic Radiation Protection

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Cosmic QCD Axions As Gravitoelectromagnetic Dark Matter

by Tommy on 28/10/2015


Axions and Dark Matter, Qiaoli Yang, A Contribution to the Special Issue of the Modern Physics Letters A “Dark Matter Particle Candidates” (10 September 2015)

Dark matter particles constitute 23% of the total energy density of our universe and their exact properties are still unclear besides that they must be very cold and weakly interacting with the standard model particles. Many beyond standard model theories provide proper candidates to serve as the dark matter. The axions were introduced to solve the strong CP problem and later turned out to be a very attractive dark matter candidate. In this paper, we briefly review the physics of axions and the axion dark matter.

See also: http://arxiv.org/abs/1510.02002

Axions/Axion like particles and the CMB asymmetric dipole, Qiaoli Yang, A Contribution to the Special Issue “Composite dark matter” in the International Journal of Modern Physics D (7 October 2015)

Axions and axion like particles are very attractive dark matter candidates. In this review, we briefly investigate how the cosmological observations reveal the existence of dark matter and some unique properties of axions/axion like particles which make them more interesting.

These articles are extremely succinct.

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Contraction Superoperators – A Mathematical Breakthrough In Theoretical Physics

by Tommy on 27/10/2015


Microscopic theory of phase transitions in a critical region, Vitaly V. Kocharovsky and Vladimir V. Kocharovsky, Physica Scripta, 90, 108002 (9 September 2015), DOI:10.1088/0031-8949/90/10/108002

The problem of finding a microscopic theory of phase transitions across a critical point is a central unsolved problem in theoretical physics. We find a general solution to that problem and present it here for the cases of Bose-Einstein condensation in an interacting gas and ferromagnetism in a lattice of spins, interacting via a Heisenberg or Ising Hamiltonian. For Bose-Einstein condensation, we present the exact, valid for the entire critical region, equations for the Green functions and order parameter, that is a critical-region extension of the Beliaev-Popov and Gross-Pitaevskii equations. For the magnetic phase transition, we find an exact theory in terms of constrained bosons in a lattice and obtain similar equations for the Green functions and order parameter. In particular, we outline an exact solution for the three-dimensional Ising model.

See also: http://arxiv.org/abs/1510.07333

Microscopic theory of a phase transition in a critical region: Bose-Einstein condensation in an interacting gas, Vitaly V. Kocharovsky and Vladimir V. Kocharovsky, Physics Letters A, 379, 466-470 (20 February 2015), DOI:10.1016/j.physleta.2014.10.052

We present a microscopic theory of the second order phase transition in an interacting Bose gas that allows one to describe formation of an ordered condensate phase from a disordered phase across an entire critical region continuously. We derive the exact fundamental equations for a condensate wave function and the Green functions, which are valid both inside and outside the critical region. They are reduced to the usual Gross-Pitaevskii and Beliaev-Popov equations in a low-temperature limit outside the critical region. The theory is readily extendable to other phase transitions, in particular, in the physics of condensed matter and quantum fields.

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Giant and Terrestrial Planet Planetary Formation From Pebbles

by Tommy on 27/10/2015


Growing the terrestrial planets from the gradual accumulation of sub-meter sized objects, Harold F. Levison, Katherine A. Kretke, Kevin Walsh and William Bottke (7 October 2015)

Building the terrestrial planets has been a challenge for planet formation models. In particular, classical theories have been unable to reproduce the small mass of Mars and instead predict that a planet near 1.5 AU should roughly be the same mass as the Earth. Recently, a new model called Viscous Stirred Pebble Accretion (VSPA) has been developed that can explain the formation of the gas giants. This model envisions that the cores of the giant planets formed from 100 to 1000 km bodies that directly accreted a population of pebbles — sub-meter sized objects that slowly grew in the protoplanetary disk. Here we apply this model to the terrestrial planet region and find that it can reproduce the basic structure of the inner Solar System, including a small Mars and a low-mass asteroid belt. Our models show that for an initial population of planetesimals with sizes similar to those of the main belt asteroids, VSPA becomes inefficient beyond ∼1.5 AU. As a result, Mars’s growth is stunted and nothing large in the asteroid belt can accumulate.

See also: http://www.nature.com/nature/journal/v524/n7565/full/nature14675.html

Growing the gas-giant planets by the gradual accumulation of pebbles, Harold F. Levison, Katherine A. Kretke and Martin J. Duncan, Nature, 524, 322–324 (20 August 2015), doi:10.1038/nature14675

It is widely held that the first step in forming gas-giant planets, such as Jupiter and Saturn, was the production of solid ‘cores’ each with a mass roughly ten times that of the Earth. Getting the cores to form before the solar nebula dissipates (in about one to ten million years) has been a major challenge for planet formation models. Recently models have emerged in which ‘pebbles’ (centimetre-to-metre-sized objects) are first concentrated by aerodynamic drag and then gravitationally collapse to form objects 100 to 1,000 kilometres in size. These ‘planetesimals’ can then efficiently accrete left-over pebbles and directly form the cores of giant planets. This model is known as ‘pebble accretion’; theoretically, it can produce cores of ten Earth masses in only a few thousand years. Unfortunately, full simulations of this process show that, rather than creating a few such cores, it produces a population of hundreds of Earth-mass objects that are inconsistent with the structure of the Solar System. Here we report that this difficulty can be overcome if pebbles form slowly enough to allow the planetesimals to gravitationally interact with one another. In this situation, the largest planetesimals have time to scatter their smaller siblings out of the disk of pebbles, thereby stifling their growth. Our models show that, for a large and physically reasonable region of parameter space, this typically leads to the formation of one to four gas giants between 5 and 15 astronomical units from the Sun, in agreement with the observed structure of the Solar System.

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The Surface Structure of Bismuth Bi (110) Investigated in 2006

by Tommy on 24/10/2015


Structural determination of a low-symmetry surface by low-energy electron diffraction and ab initio calculations: Bi(110), J. Sun, A. Mikkelsen, M. Fuglsang Jensen, Y.M. Koroteev, G. Bihlmayer, E.V. Chulkov, D.L. Adams, Ph. Hofmann and K. Pohl (30 June 2006)

The surface structure of Bi(110) has been investigated by low-energy electron diffraction (LEED) intensity analysis and by first-principles calculations. Diffraction patterns at a sample temperature of 110 K and normal incidence reveal a bulk truncated (1×1) surface without indication of any structural reconstruction despite the presence of dangling bonds on the surface layer. Good agreement is obtained between the calculated and measured diffraction intensities for this complex, low-symmetry surface containing only one mirror-plane symmetry element. No significant interlayer spacing relaxations are found. The Debye temperature for the surface layer is found to be lower than in the bulk, which is indicative of larger vibrational atomic amplitudes at the surface. Meanwhile, the second layer shows a Debye temperature close to the bulk value. The experimental results for the relaxations agree well with those of our first-principles calculation.

I finally got around to looking this up on the ArXiv.

This was the state of the art in 2006.

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Hubble Space Telescope Frontier Fields Deep Early Galaxies

by Tommy on 23/10/2015
Hubble ESA Frontier Field Galaxy Cluster

Hubble ESA Frontier Field Galaxy Cluster

Somebody left a light on in there.

Bad Baby Blob!

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Boron Nitride Encapsulated Phosphorene Field Effect Device

by Tommy on 23/10/2015


Quantum Hall Effect in n-Type Few-layer Black Phosphorus, G. Long, S. G. Xu, Z. F. Wu, T. Y. Han, J. X. Z. Lin, J. Y. Shen, Y. Han, W. K. Wong, J. Q. Hou, R. Lortz and N. Wang (22 October 2015)

In this study, we demonstrate that high-quality and atomically thin black phosphorus (BP) field-effect devices show interesting features of quantum Hall effects and Shubnikov-de Haas oscillations at intermediate strengths of magnetic field. The ability to observe quantum phenomena largely depends on the improved quality of BP by encapsulating it in hexagonal boron nitride (h-BN) sheets to form h-BN/BP/h-BN heterostructures. The combination of a selective etching process for h-BN/BP/h-BN heterostructure and deposition of Ti/Au electrodes with matching work function with BP is crucial to produce high-quality Ohmic contacts on the electron side (n-type) of BP channels. Ultrahigh electron mobility enables us to systematically study, for the first time, the intrinsic quantum properties of n-type few-layered BP, such as the Berry phase, effective electron cyclotron mass, and metal insulator transition at low carrier concentrations (1011cm−2).

Behold the nanoheterostructure era!

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