In this paper, we show that massive envelopes made of highly compressed normal matter surrounding dark objects (DEOs) can curve the surrounding spacetime and make the systems observationally indistinguishable from the...In this paper, we show that massive envelopes made of highly compressed normal matter surrounding dark objects (DEOs) can curve the surrounding spacetime and make the systems observationally indistinguishable from their massive black hole counterparts. DEOs are new astrophysical objects that are made up of entropy-free incompressible supranuclear dense superfluid (SuSu-matter), embedded in flat spacetimes and invisible to outside observers, practically trapped in false vacua. Based on highly accurate numerical modelling of the internal structures of pulsars and massive neutron stars, and in combination with using a large variety of EOSs, we show that the mass range of DEOs is practically unbounded from above: it spans those of massive neutron stars, stellar and even supermassive black holes: thanks to the universal maximum density of normal matter, , beyond which normal matter converts into SuSu-matter. We apply the scenario to the Crab and Vela pulsars, the massive magnetar PSR J0740 6620, the presumably massive NS formed in GW170817, and the SMBHs in Sgr A* and M87*. Our numerical results also reveal that DEO-Envelope systems not only mimic massive BHs nicely but also indicate that massive DEOs can hide vast amounts of matter capable of turning our universe into a SuSu-matter-dominated one, essentially trapped in false vacua.展开更多
Supermassive DEOs (SMDEOs) are cosmologically evolved objects made of irreducible incompressible supranuclear dense superfluids: The state we consider to govern the matter inside the cores of massive neutron stars. Th...Supermassive DEOs (SMDEOs) are cosmologically evolved objects made of irreducible incompressible supranuclear dense superfluids: The state we consider to govern the matter inside the cores of massive neutron stars. These cores are practically trapped in false vacua, rendering their detection by outside observers impossible. Based on massive parallel computations and theoretical investigations, we show that SMDEOs at the centres of spiral galaxies that are surrounded by massive rotating torii of normal matter may serve as powerful sources for gravitational waves carrying away roughly 1042 erg/s. Due to the extensive cooling by GWs, the SMDEO-Torus systems undergo glitching, through which both rotational and gravitational energies are abruptly ejected into the ambient media, during which the topologies of the embedding spacetimes change from curved into flatter ones, thereby triggering a burst gravitational energy of order 1059 erg. Also, the effects of glitches found to alter the force balance of objects in the Lagrangian-L1 region between the central SMDEO-Torus system and the bulge, enforcing the enclosed objects to develop violent motions, that may explain the origin of the rotational curve irregularities observed in the innermost part of spiral galaxies. Our study shows that the generated GWs at the centres of galaxies, which traverse billions of objects during their outward propagations throughout the entire galaxy, lose energy due to repeatedly squeezing and stretching the objects. Here, we find that these interactions may serve as damping processes that give rise to the formation of collective forces f∝m(r)/r, that point outward, endowing the objects with the observed flat rotation curves. Our approach predicts a correlation between the baryonic mass and the rotation velocities in galaxies, which is in line with the Tully-Fisher relation. The here-presented self-consistent approach explains nicely the observed rotation curves without invoking dark matter or modifying Newtonian gravitation in the low-field展开更多
Exploring the state of ultra-cold supranuclear dense matter that makes up the cores of massive neutron stars is one of the greatest unresolved problems in modern physics. In this letter, we show that when the interior...Exploring the state of ultra-cold supranuclear dense matter that makes up the cores of massive neutron stars is one of the greatest unresolved problems in modern physics. In this letter, we show that when the interiors of pulsars are made of compressible and dissipative normal matter, the commonly used solution procedures combined with the known EOSs yield widely scattered solutions and poorly determined radii. A remarkable agreement emerges, however, if pulsars harbour cores that are made of incompressible entropy-free superfluids (SuSu-matter) embedded in flat spacetimes. Such supranuclear dense matter should condensate to form false vacua as predicated by non-perterbative QCD vacuum. The solutions here are found to be physically consistent and mathematically elegant, irrespective of the object’s mass. Based thereon, we conclude that the true masses of massive NSs may differ significantly from those revealed by direct observation.展开更多
Recently, it was argued that the energy density of the supranuclear dense matter inside the cores of massive neutron stars must have reached the , beyond which supranuclear dense matter becomes incompressible entropy-...Recently, it was argued that the energy density of the supranuclear dense matter inside the cores of massive neutron stars must have reached the , beyond which supranuclear dense matter becomes incompressible entropy-free gluon-quark superfluid. As this matter is also confined and embedded in flat spacetime, it is Lorentz invariant and could be treated as vacuum. The lower bound of matter in the universe may be derived using the following observational constraints: 1) The average energy density of the observable universe is erg/cc, 2) The observable universe is remarkably flat, and 3) the Hubble constant is a slowly decreasing function of cosmic time. Based thereon, I argue that the energy density in nature should be bounded from below by the average density of our vast and flat parent universe, , which is, in turn, comparable to the vacuum energy density , and amounts to erg/cc. When the total energy density is measured relative to , then both GR and Newtonian field equations may consistently model the gravitational potential of the parent universe without invoking cosmological constants. Relying on the recently proposed unicentric model of the observable universe, UNIMOUN, the big bang must have warped the initially flat spacetime into a curved one, though the expansion of the fireball doomed the excited energy state to diffuse out and return back to the ground energy state that governs the flat spacetime of our vast parent universe.展开更多
In view of the growing difficulties of ΛCDM-cosmologies to compete with recent highly accurate cosmological observations, I propose the alternative model: the Unicentric Model of the Observable UNiverse (UNIMOUN). Th...In view of the growing difficulties of ΛCDM-cosmologies to compete with recent highly accurate cosmological observations, I propose the alternative model: the Unicentric Model of the Observable UNiverse (UNIMOUN). The model relies on employing a new time-dependent -metric for the GR field equations, which enables reversible phase transitions between normal compressible fluids and incompressible quantum superfluids, necessary for studying the cosmic evolution of the observable universe. The main properties of UNIMOUN read: 1) The observable universe was born in a flat spacetime environment, which is a tiny fraction of our infinitely large and flat parent universe, 2) Our big bang (BB) happened to occur in our neighbourhood, thereby endowing the universe the observed homogeneity and isotropy, 3) The energy density in the universe is upper-bounded by the universal critical density , beyond which matter becomes purely incompressible, rendering formation of physical singulareties, and in particular black holes, impossible, 4) Big bangs are neither singular events nor invoked by external forces, but rather, they are common self-sustaining events in our parent universe, 5) The progenitors of BBs are created through the merger of cosmically dead and inactive neutron stars and/or through “supermassive black holes” that are currently observed at the centres of most massive galaxies, 6) The progenitors are made up of purely incompressible entropy-free superconducting gluon- quark superfluids with (SuSu-matter), which endows these giant objects measurable sizes, 7) Spacetimes embedding SuSu-matter are conformally flat. It is shown that UNIMOUN is capable of dealing with or providing answers to several fundamental open questions in astrophysics and cosmology without invoking inflation, dark matter or dark energy.展开更多
Based on the theory and observations of glitching pulsars, we show that the ultra-cold supranuclear dense matter inside the cores of massive pulsars should condensate in vacua, as predicated by non-perturbative QCD. T...Based on the theory and observations of glitching pulsars, we show that the ultra-cold supranuclear dense matter inside the cores of massive pulsars should condensate in vacua, as predicated by non-perturbative QCD. The trapped matter here forms false vacuums embedded in flat spacetimes and completely disconnected from the outside world. Although the vacuum expectation value here vanishes, the masses and sizes of these incompressible superfluid cores are set to grow with cosmic times, in accord with the Onsager-Feynman superfluidity analysis. We apply our scenario to several well-studied pulsars, namely the Crab, Vela, PSR J0740+6620 and find that the trapped mass-contents in their cores read {0.15,0.55,0.64}, implying that their true masses are {1.55,2.35,2.72} , respectively. Based thereon, we conclude that: 1) The true masses of massive pulsars and neutron stars are much higher than detected by direct observations and, therefore, are unbounded from above, 2) The remnant of the merger event in GW170817 should be a massive NS harbouring a core with 1.66 .展开更多
Recently, a unicentric model of the observable universe (UNIMOUN) was proposed. Accordingly, big bangs are common events in our infinitely large, flat, homogeneous and isotropic parent universe. Their progenitors are ...Recently, a unicentric model of the observable universe (UNIMOUN) was proposed. Accordingly, big bangs are common events in our infinitely large, flat, homogeneous and isotropic parent universe. Their progenitors are clusters of cosmically dead and massive neutron stars that merged after reaching the ultimate lowest quantum energy state, where the matter is in an incompressible superconducting gluon-quark superfluid state and zero-entropy, hence granting the resulting progenitors measurable sizes and immunity to collapsing into black holes. Our big bang happened to occur in our neighbourhood, thereby enduing the universe, the observed homogeneity and isotropy. As the enclosed mass of the progenitor was finite, the dynamically expanding curved spacetimes embedded the fireball started flattening to finally diffuse into the flat spacetime of the parent universe. By means of general relativistic numerical hydrodynamical calculations, we use the H-metric to follow the time-evolution of the spacetime embedding the progenitor during the hadronization and the immediately following epochs. Based thereon, we find that the kinetic energy of newly created normal matter increases with distance in a self-similar manner, imitating thereby outflows of nearly non-interacting particles. On cosmic time scales, this behaviour yields a Hubble parameter, H(t), which decreases slowly with the distance from the big bang event. Given the sensitivity of the data of the Cosmic Microwave Background (CMB) from Planck to the underlying cosmological model, we conclude that UNIMOUN is a viable alternative to ΛCMD-cosmologies.展开更多
A meshless approach, called the rigid-plastic reproducing kernel particle method （RKPM）, is presented for three-dimensional （3D） bulk metal forming simulation. The approach is a combination of RKPM with the flow t...A meshless approach, called the rigid-plastic reproducing kernel particle method （RKPM）, is presented for three-dimensional （3D） bulk metal forming simulation. The approach is a combination of RKPM with the flow theory of 3D rigid-plastic mechanics. For the treatments of essential boundary conditions and incompressibility constraint, the boundary singular kernel method and the modified penalty method are utilized, respectively. The arc-tangential friction model is employed to treat the contact conditions. The compression of rectangular blocks, a typical 3D upsetting operation, is analyzed for different friction conditions and the numerical results are compared with those obtained using commercial rigid-plastic FEM （finite element method） software Deform^3D. As results show, when handling 3D plastic deformations, the proposed approach eliminates the need of expensive meshing and remeshing procedures which are unavoidable in conventional FEM and can provide results that are in good agreement with finite element predictions.展开更多
This work addresses the question of the fluid dependence of the non-dimensional parameters of seismic anisotropy. It extends the classic theory of the fluid-dependence of elasticity, and applies the approximation of w...This work addresses the question of the fluid dependence of the non-dimensional parameters of seismic anisotropy. It extends the classic theory of the fluid-dependence of elasticity, and applies the approximation of weak seismic anisotropy. The analysis shows that reliance upon the classic theory leads to oversimplified conclusions. Extending the classic theory introduces new parameters（which must be experimentally determined） into the conclusions, making their application in the field context highly problematic.展开更多
The multi-messenger observations of the merger event in GW170817 did not rule out the possibility that the remnant might be a dynamically stable neutron star with <img src="Edit_01b04c31-b94c-4b32-bd17-d6383ca...The multi-messenger observations of the merger event in GW170817 did not rule out the possibility that the remnant might be a dynamically stable neutron star with <img src="Edit_01b04c31-b94c-4b32-bd17-d6383ca16545.bmp" alt="" />. Based on this and other recent events, I argue that the universal maximum density hypothesis should be revived. Accordingly, the central densities in the cores of ultra-compact objects must be upper-limited by the critical density number <em>n</em><sub><em>cr</em></sub>, beyond which supranuclear dense matter becomes purely incompressible. Based on the spacetime-matter coupling in GR, it is shown that the topology of spacetime embedding incompressible quantum fluids with <em>n</em>=<em style="white-space:normal;">n</em><sub style="white-space:normal;"><em>cr </em></sub>must be Minkowski flat, which implies that spacetime at the background of ultra-compact objects should be bimetric.展开更多
文摘In this paper, we show that massive envelopes made of highly compressed normal matter surrounding dark objects (DEOs) can curve the surrounding spacetime and make the systems observationally indistinguishable from their massive black hole counterparts. DEOs are new astrophysical objects that are made up of entropy-free incompressible supranuclear dense superfluid (SuSu-matter), embedded in flat spacetimes and invisible to outside observers, practically trapped in false vacua. Based on highly accurate numerical modelling of the internal structures of pulsars and massive neutron stars, and in combination with using a large variety of EOSs, we show that the mass range of DEOs is practically unbounded from above: it spans those of massive neutron stars, stellar and even supermassive black holes: thanks to the universal maximum density of normal matter, , beyond which normal matter converts into SuSu-matter. We apply the scenario to the Crab and Vela pulsars, the massive magnetar PSR J0740 6620, the presumably massive NS formed in GW170817, and the SMBHs in Sgr A* and M87*. Our numerical results also reveal that DEO-Envelope systems not only mimic massive BHs nicely but also indicate that massive DEOs can hide vast amounts of matter capable of turning our universe into a SuSu-matter-dominated one, essentially trapped in false vacua.
文摘Supermassive DEOs (SMDEOs) are cosmologically evolved objects made of irreducible incompressible supranuclear dense superfluids: The state we consider to govern the matter inside the cores of massive neutron stars. These cores are practically trapped in false vacua, rendering their detection by outside observers impossible. Based on massive parallel computations and theoretical investigations, we show that SMDEOs at the centres of spiral galaxies that are surrounded by massive rotating torii of normal matter may serve as powerful sources for gravitational waves carrying away roughly 1042 erg/s. Due to the extensive cooling by GWs, the SMDEO-Torus systems undergo glitching, through which both rotational and gravitational energies are abruptly ejected into the ambient media, during which the topologies of the embedding spacetimes change from curved into flatter ones, thereby triggering a burst gravitational energy of order 1059 erg. Also, the effects of glitches found to alter the force balance of objects in the Lagrangian-L1 region between the central SMDEO-Torus system and the bulge, enforcing the enclosed objects to develop violent motions, that may explain the origin of the rotational curve irregularities observed in the innermost part of spiral galaxies. Our study shows that the generated GWs at the centres of galaxies, which traverse billions of objects during their outward propagations throughout the entire galaxy, lose energy due to repeatedly squeezing and stretching the objects. Here, we find that these interactions may serve as damping processes that give rise to the formation of collective forces f∝m(r)/r, that point outward, endowing the objects with the observed flat rotation curves. Our approach predicts a correlation between the baryonic mass and the rotation velocities in galaxies, which is in line with the Tully-Fisher relation. The here-presented self-consistent approach explains nicely the observed rotation curves without invoking dark matter or modifying Newtonian gravitation in the low-field
文摘Exploring the state of ultra-cold supranuclear dense matter that makes up the cores of massive neutron stars is one of the greatest unresolved problems in modern physics. In this letter, we show that when the interiors of pulsars are made of compressible and dissipative normal matter, the commonly used solution procedures combined with the known EOSs yield widely scattered solutions and poorly determined radii. A remarkable agreement emerges, however, if pulsars harbour cores that are made of incompressible entropy-free superfluids (SuSu-matter) embedded in flat spacetimes. Such supranuclear dense matter should condensate to form false vacua as predicated by non-perterbative QCD vacuum. The solutions here are found to be physically consistent and mathematically elegant, irrespective of the object’s mass. Based thereon, we conclude that the true masses of massive NSs may differ significantly from those revealed by direct observation.
文摘Recently, it was argued that the energy density of the supranuclear dense matter inside the cores of massive neutron stars must have reached the , beyond which supranuclear dense matter becomes incompressible entropy-free gluon-quark superfluid. As this matter is also confined and embedded in flat spacetime, it is Lorentz invariant and could be treated as vacuum. The lower bound of matter in the universe may be derived using the following observational constraints: 1) The average energy density of the observable universe is erg/cc, 2) The observable universe is remarkably flat, and 3) the Hubble constant is a slowly decreasing function of cosmic time. Based thereon, I argue that the energy density in nature should be bounded from below by the average density of our vast and flat parent universe, , which is, in turn, comparable to the vacuum energy density , and amounts to erg/cc. When the total energy density is measured relative to , then both GR and Newtonian field equations may consistently model the gravitational potential of the parent universe without invoking cosmological constants. Relying on the recently proposed unicentric model of the observable universe, UNIMOUN, the big bang must have warped the initially flat spacetime into a curved one, though the expansion of the fireball doomed the excited energy state to diffuse out and return back to the ground energy state that governs the flat spacetime of our vast parent universe.
文摘In view of the growing difficulties of ΛCDM-cosmologies to compete with recent highly accurate cosmological observations, I propose the alternative model: the Unicentric Model of the Observable UNiverse (UNIMOUN). The model relies on employing a new time-dependent -metric for the GR field equations, which enables reversible phase transitions between normal compressible fluids and incompressible quantum superfluids, necessary for studying the cosmic evolution of the observable universe. The main properties of UNIMOUN read: 1) The observable universe was born in a flat spacetime environment, which is a tiny fraction of our infinitely large and flat parent universe, 2) Our big bang (BB) happened to occur in our neighbourhood, thereby endowing the universe the observed homogeneity and isotropy, 3) The energy density in the universe is upper-bounded by the universal critical density , beyond which matter becomes purely incompressible, rendering formation of physical singulareties, and in particular black holes, impossible, 4) Big bangs are neither singular events nor invoked by external forces, but rather, they are common self-sustaining events in our parent universe, 5) The progenitors of BBs are created through the merger of cosmically dead and inactive neutron stars and/or through “supermassive black holes” that are currently observed at the centres of most massive galaxies, 6) The progenitors are made up of purely incompressible entropy-free superconducting gluon- quark superfluids with (SuSu-matter), which endows these giant objects measurable sizes, 7) Spacetimes embedding SuSu-matter are conformally flat. It is shown that UNIMOUN is capable of dealing with or providing answers to several fundamental open questions in astrophysics and cosmology without invoking inflation, dark matter or dark energy.
文摘Based on the theory and observations of glitching pulsars, we show that the ultra-cold supranuclear dense matter inside the cores of massive pulsars should condensate in vacua, as predicated by non-perturbative QCD. The trapped matter here forms false vacuums embedded in flat spacetimes and completely disconnected from the outside world. Although the vacuum expectation value here vanishes, the masses and sizes of these incompressible superfluid cores are set to grow with cosmic times, in accord with the Onsager-Feynman superfluidity analysis. We apply our scenario to several well-studied pulsars, namely the Crab, Vela, PSR J0740+6620 and find that the trapped mass-contents in their cores read {0.15,0.55,0.64}, implying that their true masses are {1.55,2.35,2.72} , respectively. Based thereon, we conclude that: 1) The true masses of massive pulsars and neutron stars are much higher than detected by direct observations and, therefore, are unbounded from above, 2) The remnant of the merger event in GW170817 should be a massive NS harbouring a core with 1.66 .
文摘Recently, a unicentric model of the observable universe (UNIMOUN) was proposed. Accordingly, big bangs are common events in our infinitely large, flat, homogeneous and isotropic parent universe. Their progenitors are clusters of cosmically dead and massive neutron stars that merged after reaching the ultimate lowest quantum energy state, where the matter is in an incompressible superconducting gluon-quark superfluid state and zero-entropy, hence granting the resulting progenitors measurable sizes and immunity to collapsing into black holes. Our big bang happened to occur in our neighbourhood, thereby enduing the universe, the observed homogeneity and isotropy. As the enclosed mass of the progenitor was finite, the dynamically expanding curved spacetimes embedded the fireball started flattening to finally diffuse into the flat spacetime of the parent universe. By means of general relativistic numerical hydrodynamical calculations, we use the H-metric to follow the time-evolution of the spacetime embedding the progenitor during the hadronization and the immediately following epochs. Based thereon, we find that the kinetic energy of newly created normal matter increases with distance in a self-similar manner, imitating thereby outflows of nearly non-interacting particles. On cosmic time scales, this behaviour yields a Hubble parameter, H(t), which decreases slowly with the distance from the big bang event. Given the sensitivity of the data of the Cosmic Microwave Background (CMB) from Planck to the underlying cosmological model, we conclude that UNIMOUN is a viable alternative to ΛCMD-cosmologies.
基金This work was supported by the National Natural Science Foundation of China （No. 50275094）.
文摘A meshless approach, called the rigid-plastic reproducing kernel particle method （RKPM）, is presented for three-dimensional （3D） bulk metal forming simulation. The approach is a combination of RKPM with the flow theory of 3D rigid-plastic mechanics. For the treatments of essential boundary conditions and incompressibility constraint, the boundary singular kernel method and the modified penalty method are utilized, respectively. The arc-tangential friction model is employed to treat the contact conditions. The compression of rectangular blocks, a typical 3D upsetting operation, is analyzed for different friction conditions and the numerical results are compared with those obtained using commercial rigid-plastic FEM （finite element method） software Deform^3D. As results show, when handling 3D plastic deformations, the proposed approach eliminates the need of expensive meshing and remeshing procedures which are unavoidable in conventional FEM and can provide results that are in good agreement with finite element predictions.
文摘This work addresses the question of the fluid dependence of the non-dimensional parameters of seismic anisotropy. It extends the classic theory of the fluid-dependence of elasticity, and applies the approximation of weak seismic anisotropy. The analysis shows that reliance upon the classic theory leads to oversimplified conclusions. Extending the classic theory introduces new parameters（which must be experimentally determined） into the conclusions, making their application in the field context highly problematic.
文摘The multi-messenger observations of the merger event in GW170817 did not rule out the possibility that the remnant might be a dynamically stable neutron star with <img src="Edit_01b04c31-b94c-4b32-bd17-d6383ca16545.bmp" alt="" />. Based on this and other recent events, I argue that the universal maximum density hypothesis should be revived. Accordingly, the central densities in the cores of ultra-compact objects must be upper-limited by the critical density number <em>n</em><sub><em>cr</em></sub>, beyond which supranuclear dense matter becomes purely incompressible. Based on the spacetime-matter coupling in GR, it is shown that the topology of spacetime embedding incompressible quantum fluids with <em>n</em>=<em style="white-space:normal;">n</em><sub style="white-space:normal;"><em>cr </em></sub>must be Minkowski flat, which implies that spacetime at the background of ultra-compact objects should be bimetric.
