Quark Matter Research Papers - Academia.edu (original) (raw)

The discovery of pulsars with masses of ∼ 2 solar masses (2 M ⊙) provides strong support for the existence of strange quark matter in nature [1]. The discovery of ultra-dense pulsar planets [2] indicates that strange quark matter objects need not be gravitationally confined and supports the hypothesis that strange quark matter is a stable state of matter [3]. Stable quark matter nuggets have been proposed as an explanation for dark matter [4], being consistent with astronomical constraints if they have masses, M, in the range 10 5 kg M 10 16 kg. Quark matter objects in this mass range would have diameters of order 1 mm, extremely high densities (10 15 kg m −3), and the mass of a small asteroid. Quark nuggets would not be " dark, " but would interact with ordinary matter and with photons, satisfying astronomical constraints on dark matter through their relative rarity instead of through a lack of interactions with photons or baryons [5]. Under very general assumptions primordial quark nuggets would attract nearby normal matter and thus should be expected to possess ordinary matter mantles, appearing superficially to be ordinary planetesimals or asteroids. For reasonable models of galactic dark matter velocity distributions the total amount of captured dark matter in a solar-type protoplanetary nebula might be as large as ∼ 10 −8 to 10 −6 M ⊙ ; these quark nuggets would reside today in the cores of the Sun, planets and asteroids. The quark nugget theory is likely to be confirmed or denied as a consequence of the exploration and mining of 100-meter sized Near Earth Objects (NEO), as the existence of a quark core should be evident to in situ spacecraft examination of such small bodies. Such " strange asteroids " would be dominated by the mass of their strange matter core, having a high density and possibly also a strong magnetic field [6]. Strange asteroids would, however, possess relatively small moments of inertia, and thus could be spun up to unusually fast rotation rates under Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) radiative torquing [7]. Small NEO do indeed contain a population apparently consistent with these predictions, suggesting that some 200-meter diameter or smaller asteroids may contain cores of strange quark matter, and that these objects should be sought among the extremely rapidly rotating small NEO [8]. If some small asteroids are indeed strange asteroids their quark matter cores could be extracted using the techniques being developed for asteroid mining. The discovery of even a single quark nugget in the Solar System would of course be of immense scientific value, but would also likely be important in the economic development of the solar system. At low temperatures and high densities the lowest energy quark matterstate appears to be the so-called Color-Flavor-Locked (CFL) superconducting state [9, 10, 11, 12, 13, 14]. CFL quark matter may be stable at zero temperature, and if it made up the dark matter it would be the fundamental state of matter, both more stable than 56 Fe and more prevalent than normal hadronic matter. It is not possible to model strange quark matter properly with lattice QCD [15], and so it is likely that quark nuggets will reveal new QCD physics, but it appears likely that quark matter in the solar system could be used as an energy source, enabling nuclear fusion either through the creation of antimatter through color Andreev reflection [16, 17], or by using small quark matter fragments as a catalysis for pynconuclear fusion [18]. While of course speculative, this energy source could be suitable for propelling starships to a substantial fraction of the speed of light, and, assuming the existance of strange quark matter, could be realized in our Solar System with existing and near-term developments in technology. References [1] T. Klähn, R. Łastowiecki, and D. Blaschke. Implications of the measurement of pulsars with two solar masses for quark matter in compact stars and heavy-ion collisions: A Nambu-Jona-Lasinio model case study. Phys. Rev. D,