#nongravitative

[materialsscienceandengineering]

The Low-Mass Dark Matter Frontier

Traditional searches for dark matter rely on giant detectors that look for particles heavier than a proton, but sights are turning to smaller experiments with sensitivity to lighter-mass particles.

[...]

Extensive evidence suggests that a staggering 85% of the matter in our Universe is dark matter. This substance interacts gravitationally with itself and with ordinary matter, but whatever other interactions it has with regular matter have eluded detection. For this reason, the presence of dark matter is inferred indirectly—from the properties of the cosmic microwave background, from the distribution and velocities of stars, galaxies, and galaxy clusters, and from the gravitational lensing of distant light sources.

The most plausible explanation for dark matter is that it consists of one or more new particles that are not described by the standard model of particle physics. Yet despite decades of searching, no convincing laboratory evidence for dark matter exists. Many basic properties of dark matter particles therefore remain unknown, such as their mass, spin, and whether they have nongravitational interactions with known standard model particles.

Read more.

[thenewenlightenmentage]

Does Dark Matter Harbor Life?

An invisible civilization could be living right under your nose.

By Lisa Randall

Illustrations by Jackie Ferrentino

Even though we know that ordinary matter accounts for only about one-twentieth of the universe’s energy and a sixth of the total energy carried by matter (with dark energy constituting the remaining portion), we nonetheless consider ordinary matter to be the truly important constituent. With the exception of cosmologists, almost everyone’s attention is focused on the ordinary matter component, which you might have thought to be largely insignificant according to the energy accounting.

We of course care more about ordinary matter because we are made of the stuff—as is the tangible world in which we live. But we also pay attention because of the richness of its interactions. Ordinary matter interacts through the electromagnetic, the weak, and the strong nuclear forces—helping the visible matter of our world to form complex, dense systems. Not only stars, but also rocks, oceans, plants, and animals owe their very existence to the nongravitational forces of nature through which ordinary matter interacts. Just as a beer’s small-percentage alcohol content affects carousers far more than the rest of the drink, ordinary matter, though carrying a small percentage of the energy density, influences itself and its surroundings much more noticeably than something that just passes through.

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[didanawisgi]

CONCLUSIONS 

In conclusion, ‘Oumuamua is described as a piece of debris of a dwarf interstellar comet, which — following Bortle’s rule for survival of comets in orbits of small perihelion distance — had disintegrated at a time not long before perihelion, possibly because of its nucleus’ rotational breakup. Conceptualized as a monstrous, very irregularly shaped and devolatilized fluffy aggregate of loosely-bound dust grains, of extremely high porosity and 107 g in mass (Sekanina & Kracht 2018), this model of ‘Oumuamua provides an opportunity to consistently explain its nongravitational acceleration as an effect of solar radiation pressure and to emphasize a chance that a number of its observed properties, including the lack of activity, tumbling, radiation pressure effect, and the inferred appearance, morphology, and elongated shape are of recent origin, not inherent to the object that was entering the inner Solar System in early 2017.

[yestheearthisflat-blog]

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Thanks for the vid @tech_insider BUT if you ixnay #gravity would a #flatEarth be possible? Not sure what alternative theories exist that support a #nongravitational world just playing Devil's advocate 👹🤔 • #TheEarthisFlat 🌎🕳 #Freementalhealthcare for kids! 💸💭🚑 • Kudos for the sports examples! ⚾️👍🏻 (part 1) (at Yes, the Earth is flat Inc.)

[babyawacs]

#entanglement #qubit #neutrino #101 .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylev

#entanglement #qubit #neutrino #101 .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylev

#entanglement #qubit #neutrino #101 .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa

Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylevels fail as neutrinodisrupted

#rhetoric #neutrino #qubit #question

Would a cumulative bonding flux particle. Measured from within the system.…

[jdpink]

This result should have raised a red flag, as it amounts to a powerful argument against the nongravitational acceleration in the orbital motion of ‘Oumuamua having been induced by the sublimation of water ice. It is unfortunate that this major finding is noted by Micheli et al. only peripherally in the text and Table 1, but not explicitly in the executive summary. Since Trilling et al.’s (2018) results, based on the nondetection of ‘Oumuamua with the Spitzer Space Telescope, demonstrate conclusively that the nongravitational acceleration could under no circumstances be a corollary of the sublimation of carbon dioxide or carbon monoxide, I focus in this paper on providing

a wealth of arguments to support the notion that the acceleration cannot in fact be a product of the sublimation of water ice either…

The net result of this extensive search was that the number of objects with a radial nongravitational acceleration comparable to, or greater than, ‘Oumuamua’s acceleration

was exactly one — C/1998 P1 (Williams), whose perihelion distance was 1.146 AU. However, as illustrated in Figure 1, the findings are complicated by the different nongravitational laws employed… . In any case, ‘Oumuamua’s orbital anomaly does not compare well with the outgassing-driven effects in the motions of long-period comets, exceeding even the largest among them by a sizable margin. In summary, there appears to be no object whose outgassing-driven nongravitational effects and appearance both resemble ‘Oumuamua’s…

This outcome demonstrates that the only plausible solution is the disk, paralleling the result of a pancake vs cigar comparison examined in Section 9 of Sekanina (2019b).

In the context of ‘Oumuamua’s extremely low bulk density inferred from the considerations in the previous sections, it is noted that Kataoka et al. (2013) provide

a pathway for long-term growth of a fluffy aggrerate of submicron-sized dust grains into a planetesimal in a protoplanetary disk (see also Kataoka 2017). According to

these authors, the initial assembly of grains, each 10−15 g in mass and of material density, reaches eventually a terminal mass of 1018 g and a diameter of 10 km.

The aggregate’s slow compaction, leading to an increase in the bulk density by about one order of magnitude by the time the mass is some 100 g and diameter 1 m, is largely a product of quasi-static compression by ambient gas in the protoplanetary disk. However, in the mass range from 10 kg to a million tons (spanning eight orders of magnitude!) the bulk density is remarkably flat, staying between 0.0002 and 0.0004 g cm−3 at all times until self-gravity sets in.

https://arxiv.org/pdf/1905.00935.pdf

[venitisblr-blog]

AXION-GLUON INTERACTION

  The gravitational pull of dark matter is observed through its effect on the rotations of galaxies. But dark matter could also interact nongravitationally with visible matter. Researchers have now used spin-precession experiments in atoms and neutrons to search for signatures of nongravitational interactions involving dark matter candidates called axions. While the search came up empty handed,…

[arxt1]

Jeans mass-radius relation of self-gravitating Bose-Einstein condensates and typical parameters of the dark matter particle. (arXiv:2011.01038v1 [gr-qc])

We study the Jeans mass-radius relation of Bose-Einstein condensate dark matter in Newtonian gravity. We show at a general level that it is similar to the mass-radius relation of Bose-Einstein condensate dark matter halos [P.H. Chavanis, Phys. Rev. D {\bf 84}, 043531 (2011)]. Bosons with a repulsive self-interaction generically evolve from the Thomas-Fermi regime to the noninteracting regime as the Universe expands. In the Thomas-Fermi regime, the Jeans radius remains approximately constant while the Jeans mass decreases. In the noninteracting regime, the Jeans radius increases while the Jeans mass decreases. Bosons with an attractive self-interaction generically evolve from the nongravitational regime to the noninteracting regime as the Universe expands. In the nongravitational regime, the Jeans radius and the Jeans mass increase. In the noninteracting regime, the Jeans radius increases while the Jeans mass decreases. The transition occurs at a maximum Jeans mass which is similar to the maximum mass of Bose-Einstein condensate dark matter halos with an attractive self-interaction. We use the mass-radius relation of dark matter halos and the observational evidence of a ``minimum halo'' (with typical radius $R\sim 1\, {\rm kpc}$ and typical mass $M\sim 10^8\, M_{\odot}$) to constrain the mass $m$ and the scattering length $a_s$ of the dark matter particle.

from gr-qc updates on arXiv.org https://ift.tt/2TLj9rF

[arxt1]

Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT. (arXiv:1906.05299v2 [hep-th] UPDATED)

Behind certain marginally trapped surfaces one can construct a geometry containing an extremal surface of equal, but not larger area. This construction underlies the Engelhardt-Wall proposal for explaining Bekenstein-Hawking entropy as a coarse-grained entropy. The construction can be proven to exist classically but fails if the Null Energy Condition is violated. Here we extend the coarse-graining construction to semiclassical gravity. Its validity is conjectural, but we are able to extract an interesting nongravitational limit. Our proposal implies Wall's ant conjecture on the minimum energy of a completion of a quantum field theory state on a half-space. It further constrains the properties of the minimum energy state; for example, the minimum completion energy must be localized as a shock at the cut. We verify that the predicted properties hold in a recent explicit construction of Ceyhan and Faulkner, which proves our conjecture in the nongravitational limit.

from gr-qc updates on arXiv.org https://ift.tt/34NHUb2

[babyawacs]

Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylevels fail as neutrinodisrupted .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa #rhet

Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylevels fail as neutrinodisrupted .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa #rhet

Earlier: ifits gravitic bondingflux entanglement higher energy fail,lower now. If nongravitic then all energylevels fail as neutrinodisrupted .@sciam @sciam @brookhavenlab @lhcb @naturephysics .@natureelectron @energy .@nnsa .@energy .@darpa @darpa

#rhetoric #neutrino #qubit #question

Would a cumulative bonding flux particle. Measured from within the system. Appear as massless.

Going thhrough…

[arxt1]

Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT. (arXiv:1906.05299v1 [hep-th])

Behind certain marginally trapped surfaces one can construct a geometry containing an extremal surface of equal, but not larger area. This construction underlies the Engelhardt-Wall proposal for explaining Bekenstein-Hawking entropy as a coarse-grained entropy. The construction can be proven to exist classically but fails if the Null Energy Condition is violated. Here we extend the coarse-graining construction to semiclassical gravity. Its validity is conjectural, but we are able to extract an interesting nongravitational limit. Our proposal implies Wall's ant conjecture on the minimum energy of a completion of a quantum field theory state on a half-space. It further constrains the properties of the minimum energy state; for example, the minimum completion energy must be localized as a shock at the cut. We verify that the predicted properties hold in a recent explicit construction of Ceyhan and Faulkner, which proves our conjecture in the nongravitational limit.

from gr-qc updates on arXiv.org http://bit.ly/2IeJJo7

[arxt1]

Curved Backgrounds in Emergent Gravity. (arXiv:1710.07262v2 [hep-th] UPDATED)

Field theories that are generally covariant but nongravitational at tree level typically give rise to an emergent gravitational interaction whose strength depends on a physical regulator. We consider emergent gravity models in which scalar fields assume the role of clock and rulers, addressing the problem of time in quantum gravity. We discuss the possibility of nontrivial dynamics for clock and ruler fields, and describe some of the consequences of those dynamics for the emergent gravitational theory.

from gr-qc updates on arXiv.org http://ift.tt/2ionTnX

[arxt1]

Curved Backgrounds in Emergent Gravity. (arXiv:1710.07262v1 [hep-th])

Field theories which are generally covariant but nongravitational at tree level typically give rise to an emergent gravitational interaction whose strength depends on a physical regulator. We consider emergent gravity models in which scalar fields assume the role of clock and rulers, addressing the problem of time in quantum gravity. We discuss the possibility of nontrivial dynamics for clock and ruler fields, and describe some of the consequences of those dynamics for the emergent gravitational theory.

from gr-qc updates on arXiv.org http://ift.tt/2ionTnX

[arxt1]

The Quantum Null Energy Condition, Entanglement Wedge Nesting, and Quantum Focusing. (arXiv:1706.04183v1 [hep-th])

We study the consequences of Entanglement Wedge Nesting for CFTs with holographic duals. The CFT is formulated on an arbitrary curved background, and we include the effects of curvature-squared couplings in the bulk. In this setup we find necessary and sufficient conditions for Entanglement Wedge Nesting to imply the Quantum Null Energy Condition in $d\leq 5$, extending its earlier holographic proofs. We also show that the Quantum Focusing Conjecture yields the Quantum Null Energy Condition as its nongravitational limit under these same conditions.

from gr-qc updates on arXiv.org http://ift.tt/2rtuNa3