We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. B...We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.展开更多
Loop quantum gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time.In this paper these issues are studied by quantizing the U(1)^(3) model,a simpli...Loop quantum gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time.In this paper these issues are studied by quantizing the U(1)^(3) model,a simplified system exhibiting features similar to general relativity.By isolating a holonomy component within the Hamiltonian constraint,a discrete relative time evolution equation for quantum states is obtained.Then,a Shrödinger-like equation is derived in the continuum limit.Thus,the physical states solving this Shrödinger-like equation can be written out.The emergence of the time parameter and its corresponding quantum operator are analyzed.It indicates the notion of a geometrical quantum time for quantum gravity.展开更多
This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and i...This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and in the quantum regime a full renormalizable quantum gauge field theory. The three fundamental constraints (hamiltonian, gaussian and diffeomorphism) were formulated in 3-dimensional spatial form within LQG in Ashtekar formulation using the notion of the Kodama state with positive cosmological constant Λ. We introduce a 4-dimensional covariant version of the 3-dimensional (spatial) hamiltonian, gaussian and diffeomorphism constraints of LQG. We obtain 32 partial differential equations for the 16 variables E<sub>mn</sub> (E-tensor, inverse densitized tetrad of the metric) and 16 variables A<sub>mn</sub> (A-tensor, gravitational wave tensor). We impose the boundary condition: for large distance the E-generated metric g(E) becomes the GR-metric g (normally Schwarzschild-spacetime). The theory based on these Ashtekar-Kodama (AK) equations, and called in the following Ashtekar-Kodama (AK-) gravity has the following properties. • For Λ = 0 the AK equations become Einstein equations, A-tensor is trivial (constant), and the E-generated metric g(E) is identical with the GR-metric g. • When the AK-equations are developed into a Λ-power series, the Λ-term yields a gravitational wave equation, which has only at least quadrupole wave solutions and becomes in the limit of large distance r the (normal electromagnetic) wave equation. • AK-gravity, as opposed to GR, has no singularity at the horizon: the singularity in the metric becomes a (very high) peak. • AK-gravity has a limit scale of the gravitational quantum region 39 μm, which emerges as the limit scale in the objective wave collapse theory of Gherardi-Rimini-Weber. In the quantum region, the AK-gravity becomes a quantum gauge theory (AK quantum gravity) with the Lie group extended SU(2) = ε-tensor-group(four generators) as gauge group and a corresponding covariant derivative. • AK quantum gravity is fully renormalizable, we derive its Lagrangian, which is dimensionally renormalizable, the normalized one-graviton wave function, the graviton propagator, and demonstrate the calculation of cross-section from Feynman diagrams.展开更多
A theory of quantum gravity has recently been developed by the author based on the concept that all forces converge to one at the moment of Creation. This primordial field can only interact with itself, as no other fi...A theory of quantum gravity has recently been developed by the author based on the concept that all forces converge to one at the moment of Creation. This primordial field can only interact with itself, as no other field exists, contrasting with the Standard Model of Particle Physics in which each elementary particle is an excitation in its own quantum field. The primordial field theory of quantum gravity has produced a model of a fermion with a mass gap, ½-integral spin, discrete charge, and magnetic moment. The mass gap is based on an existence theorem that is anchored in Yang-Mills, while Calabi-Yau anchors ½-integral spin, with charge and magnetic moment based on duality. Based on N-windings, this work is here extended to encompass fractional charge, with the result applied to quarks, yielding fermion mass and charge in agreement with experiment and novel size correlations and a unique quantum gravity-based ontological understanding of quarks.展开更多
Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests t...Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests the idea of probing the quantum nature of a variable by using it to mediate entanglement and yields theoretical and experimental insights,clarifying the operational tools needed for future gravitational experiments.We employ three methods to test the presence of entanglement:the Bell test,entanglement witness,and quantum state tomography.We also simulate the alternative scenario predicted by gravitational collapse models or due to imperfections in the experimental setup and use quantum state tomography to certify the absence of entanglement.The simulation reinforces two main lessons:(1)which path information must be first encoded and subsequently coherently erased from the gravitational field and(2)performing a Bell test leads to stronger conclusions,certifying the existence of gravity-mediated nonlocality.展开更多
Motivated by Bekenstein’s original thought that led him to his famous area-entropy formula for a black hole and by our recent study regarding the black hole dynamics, we identify the appropriate microscopic degrees o...Motivated by Bekenstein’s original thought that led him to his famous area-entropy formula for a black hole and by our recent study regarding the black hole dynamics, we identify the appropriate microscopic degrees of freedom in loop quantum gravity that are responsible for the black hole entropy. We achieve consistent results by taking the <em>j</em> = 1/2 edges as dominant and by subjecting these edges to experience quantum fluctuations at the horizon. This also leads to a modification of the value of the Immirzi parameter in the <em>SU</em>(2) framework.展开更多
<span style="line-height:1.5;">For purposes of quantization, classical gravity is normally expressed by canonical variables, namely the metric </span><img src="Edit_7bad0ce2-ecaa-4318-b3c...<span style="line-height:1.5;">For purposes of quantization, classical gravity is normally expressed by canonical variables, namely the metric </span><img src="Edit_7bad0ce2-ecaa-4318-b3c9-5bbcfa7c087e.png" alt="" style="line-height:1.5;" /><span style="line-height:1.5;"></span><span "="" style="line-height:1.5;"><span> and the momentum </span><img src="Edit_c86b710a-9b65-4220-a4e2-cff8eeab9642.png" alt="" /></span><span style="line-height:1.5;"></span><span style="line-height:1.5;">. Canonical quantization requires a proper promotion of these classical variables to quantum operators, which, according to Dirac, the favored operators should be those arising from classical variables that formed Cartesian coordinates;sadly, in this case, that is not possible. However, an affine quantization feature</span><span style="line-height:1.5;">s</span><span "="" style="line-height:1.5;"><span> promoting the metric </span><img src="Edit_d0035f64-c366-4510-9cc7-d1053f755369.png" alt="" /></span><span "="" style="line-height:1.5;"><span> and the momentric </span><img src="Edit_60c18bb8-525b-4896-ae8f-2cd6456eb6f7.png" alt="" /></span><span "="" style="line-height:1.5;"><span> to operators. Instead of these classical variables belonging to a constant zero curvature space (</span><i><span>i.e.</span></i><span>, instead of a flat space), they belong to a space of constant negative curvatures. This feature may even have its appearance in black holes, which could strongly point toward an affine quantization approach to quantize gravity.展开更多
The favored classical variables that are promoted to quantum operators are divided into three sets that feature constant positive curvatures, constant zero curvatures, as well as constant negative curvatures. This lis...The favored classical variables that are promoted to quantum operators are divided into three sets that feature constant positive curvatures, constant zero curvatures, as well as constant negative curvatures. This list covers the spin variables, the canonical variables, and the affine variables, and these three topics will be briefly reviewed. In this discussion, appropriate coherent states are introduced which are the principal items that are critical in the unification of relevant classical and quantum realms. This analysis can also serve to unify classical gravity and quantum gravity without any speculative aspects.展开更多
Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the probl...Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.展开更多
Canonical quantization (CQ) is built around [<i>Q</i>, <i>P</i>] = <i>iħ</i>1l , while affine quantization (AQ) is built around [<i>Q</i>,<i>D</i>...Canonical quantization (CQ) is built around [<i>Q</i>, <i>P</i>] = <i>iħ</i>1l , while affine quantization (AQ) is built around [<i>Q</i>,<i>D</i>] = <i>iħQ</i>, where <i>D</i> ≡ (<i>PQ</i> +<i>QP</i>) / 2 . The basic CQ operators must fit -∞ < <i>P</i>, <i>Q</i> < ∞ , while the basic AQ operators can fit -∞ < <i>P</i> < ∞ and 0 < <i>Q</i> < ∞ , -∞ < <i>Q</i> < 0 , or even -∞ < <i>Q</i> ≠ 0 < ∞ . AQ can also be the key to quantum gravity, as our simple outline demonstrates.展开更多
This paper proposes a novel approach and simplified model of Quantum Gravity based on the unification framework of Generalized Thermodynamics which suggests cross-related terms and modified equations of General Relati...This paper proposes a novel approach and simplified model of Quantum Gravity based on the unification framework of Generalized Thermodynamics which suggests cross-related terms and modified equations of General Relativity and Quantum Mechanics. To address the “background problem”, a metric tensor is introduced into stationary Schrödinger equations via curved coordinates yielding quantum spacetime variation term. Then quantum Lagrangian is added to Einstein-Hilbert functional yielding quantum stress-energy tensor. Obtained from one variational principle, two theories are linked by a common quantum spacetime field. The theory offers some interpretations of the quantum vacuum spacetime fluctuations, zero-point-fields, quantum fields shifting towards high spacetime densities, the quantum nature of spacetime, and black hole singularity.展开更多
In this work, we make a number of proposals to explain how a world of (4 + 4)-dimensions can be useful for a better understanding of both dark matter and quantum gravity. The key idea is to look for some advantage of ...In this work, we make a number of proposals to explain how a world of (4 + 4)-dimensions can be useful for a better understanding of both dark matter and quantum gravity. The key idea is to look for some advantage of considering self-dual invariants in (4 + 4)-dimensions rather than in a separate context of (1 + 3)-dimensions or (3 + 1)-dimensions. In fact, we show that by considering the duality concept in (4 + 4)-dimensions we may provide an alternative meaning of a framework for loop quantum gravity. Moreover, considering the Dirac equation in (4 + 4)-dimensions for a particle without electric charge and mass, we show that when it is projected into the (1 + 3) and (3 + 1)-worlds may describe a system with electric charge and mass. We also discuss the relation between the three physical scenarios;(4 + 4)-world, black-holes and dark matter.展开更多
It is reasonably expected 1) that a theory of quantum gravity will unify the extremes of scale currently described by General Relativity and quantum mechanics, and 2) that black holes are the crucible from which a the...It is reasonably expected 1) that a theory of quantum gravity will unify the extremes of scale currently described by General Relativity and quantum mechanics, and 2) that black holes are the crucible from which a theory of quantum gravity will emerge. In perspective, we already have a mechanism that links the local, macroscopic frame with the remote, apparently microscopic frame. A simple mathematical principle acts as a limit on D(n), suggesting a “maximum physical reality”, and that effects which are clearly perspectival at D=3 become “more real” (effectively observer-independent) with each D(n) increment. The model suggests alternative interpretations of gravitation and the quantum, entanglement, space, the Standard Model of particles and interactions, black holes, the measurement problem and the information paradox.展开更多
A theory of Quantum Gravity based on Primordial Field Theory is applied to a fundamental particle, the neutron. The result is compared to the current quantum description of the neutron bouncing in a gravitational fiel...A theory of Quantum Gravity based on Primordial Field Theory is applied to a fundamental particle, the neutron. The result is compared to the current quantum description of the neutron bouncing in a gravitational field. Our quantum gravity theory yields results in agreement with the Q-bounce experimental data, but ontologically different from quantum mechanics. The differences are summarized and imply that this experiment on a fundamental particle has the potential to radically alter the ontology of field theory.展开更多
This article gives an elementary account of the recently proposed theory of spontaneous quantum gravity. It is argued that a viable quantum theory of gravity should be falsifiable, and hence it should dynamically expl...This article gives an elementary account of the recently proposed theory of spontaneous quantum gravity. It is argued that a viable quantum theory of gravity should be falsifiable, and hence it should dynamically explain the observed absence of quantum superpositions of space-time geometries in its classical limit.展开更多
Quantum gravitational theory, based on the hypothesis of the absolute reference system, reveals the function of the effects of the gravitational field at the microscopic and macroscopic scale. The quantum nature of gr...Quantum gravitational theory, based on the hypothesis of the absolute reference system, reveals the function of the effects of the gravitational field at the microscopic and macroscopic scale. The quantum nature of gravitational potential, and the dynamics and kinetic energy of photons and elementary particles under the influence of the gravitational field are studied, and a quantum interpretation of gravitational redshift is given. There is also a complete agreement of this quantum gravitational theory with the existing experimental data.展开更多
We present a simple way to approach the hard problem of quantization of the gravitational field in four-dimensional space-time, due to non-linearity of the Einstein equations. The difficulty may be overcome when the c...We present a simple way to approach the hard problem of quantization of the gravitational field in four-dimensional space-time, due to non-linearity of the Einstein equations. The difficulty may be overcome when the cosmological constant is non-null. Treating the cosmological contribution as the energy-momentum of vacuum, and representing the metric tensor onto the tetrad of its eigenvectors, the corresponding energy-momentum and, consequently, the Hamiltonian are easily quantized assuming a correspondence rule according to which the eigenvectors are replaced by creation and annihilation operators for the gravitational field. So the geometric Einstein tensor, which is opposite in sign respect to the vacuum energy-momentum (plus the possible known matter one), is also quantized. Physical examples provided by Schwarzschild-De Sitter, Robertson-Walker-De Sitter and Kerr-De Sitter solutions are examined.展开更多
Attempts to unify Gravity Theory and Quantum Field Theory (QFT) under Loop Quantum Gravity Theory (LQG), are diverse;a dividing line between classical and quantum is sought with Schrödinger cat-state experiments....Attempts to unify Gravity Theory and Quantum Field Theory (QFT) under Loop Quantum Gravity Theory (LQG), are diverse;a dividing line between classical and quantum is sought with Schrödinger cat-state experiments. A Primordial Field Theory-based alternative is presented, and a gravity-based harmonic oscillator developed. With quantum theory applied at micro-scales and gravity theory at meso- and macro-scales, this scale-gap contributes to the conceptual problems associated with Loop Quantum Gravity. Primordial field theory, spanning all scales, is used to conceptually stretch key ideas across this gap. An LQG interpretation of the wave function associated with the oscillator is explained.展开更多
This study set out to investigate charged vector particles tunneling via horizons of a pair of accelerating rotating charged NUT black holes under the influence of quantum gravity.To this end,we use the modified Proca...This study set out to investigate charged vector particles tunneling via horizons of a pair of accelerating rotating charged NUT black holes under the influence of quantum gravity.To this end,we use the modified Proca equation incorporating generalized uncertainty principle.Applying the WKB approximation to the field equation,we obtain a modified tunneling rate and the corresponding corrected Hawking temperature for this black hole.Moreover,we analyze the graphical behavior of the corrected Hawking temperature T'_H with respect to the event horizon for the given black hole.By considering quantum gravitational effects on Hawking temperatures,we discuss the stability analysis of this black hole.For a pair of black holes,the temperature T'_H increases with the increase in rotation parameters a andω,correction parameterβ,black hole acceleration a,and arbitrary parameter k,and decreases with the increase in electric e and magnetic charges g.展开更多
The quasi-local notion of an isolated horizon is employed to study the entropy of black holes without any particular symmetry in loop quantum gravity. The idea of characterizing the shape of a horizon by a sequence of...The quasi-local notion of an isolated horizon is employed to study the entropy of black holes without any particular symmetry in loop quantum gravity. The idea of characterizing the shape of a horizon by a sequence of local areas is successfully applied in the scheme to calculate the entropy by the S O(1, 1) BF boundary theory matching loop quantum gravity in the bulk. The generating function for calculating the microscopical degrees of freedom of a given isolated horizon is obtained. Numerical computations of small black holes indicate a new entropy formula containing the quantum correction related to the partition of the horizon. Further evidence shows that, for a given horizon area, the entropy decreases as a black hole deviates from the spherically symmetric one,and the entropy formula is also well suitable for big black holes.展开更多
文摘We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.
基金funded by the National Natural Science Foundation of China(NSFC)under Grants Nos.12275022 and 11875006.
文摘Loop quantum gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time.In this paper these issues are studied by quantizing the U(1)^(3) model,a simplified system exhibiting features similar to general relativity.By isolating a holonomy component within the Hamiltonian constraint,a discrete relative time evolution equation for quantum states is obtained.Then,a Shrödinger-like equation is derived in the continuum limit.Thus,the physical states solving this Shrödinger-like equation can be written out.The emergence of the time parameter and its corresponding quantum operator are analyzed.It indicates the notion of a geometrical quantum time for quantum gravity.
文摘This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and in the quantum regime a full renormalizable quantum gauge field theory. The three fundamental constraints (hamiltonian, gaussian and diffeomorphism) were formulated in 3-dimensional spatial form within LQG in Ashtekar formulation using the notion of the Kodama state with positive cosmological constant Λ. We introduce a 4-dimensional covariant version of the 3-dimensional (spatial) hamiltonian, gaussian and diffeomorphism constraints of LQG. We obtain 32 partial differential equations for the 16 variables E<sub>mn</sub> (E-tensor, inverse densitized tetrad of the metric) and 16 variables A<sub>mn</sub> (A-tensor, gravitational wave tensor). We impose the boundary condition: for large distance the E-generated metric g(E) becomes the GR-metric g (normally Schwarzschild-spacetime). The theory based on these Ashtekar-Kodama (AK) equations, and called in the following Ashtekar-Kodama (AK-) gravity has the following properties. • For Λ = 0 the AK equations become Einstein equations, A-tensor is trivial (constant), and the E-generated metric g(E) is identical with the GR-metric g. • When the AK-equations are developed into a Λ-power series, the Λ-term yields a gravitational wave equation, which has only at least quadrupole wave solutions and becomes in the limit of large distance r the (normal electromagnetic) wave equation. • AK-gravity, as opposed to GR, has no singularity at the horizon: the singularity in the metric becomes a (very high) peak. • AK-gravity has a limit scale of the gravitational quantum region 39 μm, which emerges as the limit scale in the objective wave collapse theory of Gherardi-Rimini-Weber. In the quantum region, the AK-gravity becomes a quantum gauge theory (AK quantum gravity) with the Lie group extended SU(2) = ε-tensor-group(four generators) as gauge group and a corresponding covariant derivative. • AK quantum gravity is fully renormalizable, we derive its Lagrangian, which is dimensionally renormalizable, the normalized one-graviton wave function, the graviton propagator, and demonstrate the calculation of cross-section from Feynman diagrams.
文摘A theory of quantum gravity has recently been developed by the author based on the concept that all forces converge to one at the moment of Creation. This primordial field can only interact with itself, as no other field exists, contrasting with the Standard Model of Particle Physics in which each elementary particle is an excitation in its own quantum field. The primordial field theory of quantum gravity has produced a model of a fermion with a mass gap, ½-integral spin, discrete charge, and magnetic moment. The mass gap is based on an existence theorem that is anchored in Yang-Mills, while Calabi-Yau anchors ½-integral spin, with charge and magnetic moment based on duality. Based on N-windings, this work is here extended to encompass fractional charge, with the result applied to quarks, yielding fermion mass and charge in agreement with experiment and novel size correlations and a unique quantum gravity-based ontological understanding of quarks.
基金support from the John Templeton Foundation,The Quantum Information Structure of Spacetime(QISS)Project(qiss.fr)(the opinions expressed in this paper are those of the authors and do not necessarily reflect the views of the John Templeton Foundation)(Grant No.61466)and QISS2(Grant No.62312).
文摘Detecting gravity-mediated entanglement can provide evidence that the gravitational field obeys quantum mechanics.We report the result of a simulation of the phenomenon using a photonic platform.The simulation tests the idea of probing the quantum nature of a variable by using it to mediate entanglement and yields theoretical and experimental insights,clarifying the operational tools needed for future gravitational experiments.We employ three methods to test the presence of entanglement:the Bell test,entanglement witness,and quantum state tomography.We also simulate the alternative scenario predicted by gravitational collapse models or due to imperfections in the experimental setup and use quantum state tomography to certify the absence of entanglement.The simulation reinforces two main lessons:(1)which path information must be first encoded and subsequently coherently erased from the gravitational field and(2)performing a Bell test leads to stronger conclusions,certifying the existence of gravity-mediated nonlocality.
文摘Motivated by Bekenstein’s original thought that led him to his famous area-entropy formula for a black hole and by our recent study regarding the black hole dynamics, we identify the appropriate microscopic degrees of freedom in loop quantum gravity that are responsible for the black hole entropy. We achieve consistent results by taking the <em>j</em> = 1/2 edges as dominant and by subjecting these edges to experience quantum fluctuations at the horizon. This also leads to a modification of the value of the Immirzi parameter in the <em>SU</em>(2) framework.
文摘<span style="line-height:1.5;">For purposes of quantization, classical gravity is normally expressed by canonical variables, namely the metric </span><img src="Edit_7bad0ce2-ecaa-4318-b3c9-5bbcfa7c087e.png" alt="" style="line-height:1.5;" /><span style="line-height:1.5;"></span><span "="" style="line-height:1.5;"><span> and the momentum </span><img src="Edit_c86b710a-9b65-4220-a4e2-cff8eeab9642.png" alt="" /></span><span style="line-height:1.5;"></span><span style="line-height:1.5;">. Canonical quantization requires a proper promotion of these classical variables to quantum operators, which, according to Dirac, the favored operators should be those arising from classical variables that formed Cartesian coordinates;sadly, in this case, that is not possible. However, an affine quantization feature</span><span style="line-height:1.5;">s</span><span "="" style="line-height:1.5;"><span> promoting the metric </span><img src="Edit_d0035f64-c366-4510-9cc7-d1053f755369.png" alt="" /></span><span "="" style="line-height:1.5;"><span> and the momentric </span><img src="Edit_60c18bb8-525b-4896-ae8f-2cd6456eb6f7.png" alt="" /></span><span "="" style="line-height:1.5;"><span> to operators. Instead of these classical variables belonging to a constant zero curvature space (</span><i><span>i.e.</span></i><span>, instead of a flat space), they belong to a space of constant negative curvatures. This feature may even have its appearance in black holes, which could strongly point toward an affine quantization approach to quantize gravity.
文摘The favored classical variables that are promoted to quantum operators are divided into three sets that feature constant positive curvatures, constant zero curvatures, as well as constant negative curvatures. This list covers the spin variables, the canonical variables, and the affine variables, and these three topics will be briefly reviewed. In this discussion, appropriate coherent states are introduced which are the principal items that are critical in the unification of relevant classical and quantum realms. This analysis can also serve to unify classical gravity and quantum gravity without any speculative aspects.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No ZYGX2009X008
文摘Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.
文摘Canonical quantization (CQ) is built around [<i>Q</i>, <i>P</i>] = <i>iħ</i>1l , while affine quantization (AQ) is built around [<i>Q</i>,<i>D</i>] = <i>iħQ</i>, where <i>D</i> ≡ (<i>PQ</i> +<i>QP</i>) / 2 . The basic CQ operators must fit -∞ < <i>P</i>, <i>Q</i> < ∞ , while the basic AQ operators can fit -∞ < <i>P</i> < ∞ and 0 < <i>Q</i> < ∞ , -∞ < <i>Q</i> < 0 , or even -∞ < <i>Q</i> ≠ 0 < ∞ . AQ can also be the key to quantum gravity, as our simple outline demonstrates.
文摘This paper proposes a novel approach and simplified model of Quantum Gravity based on the unification framework of Generalized Thermodynamics which suggests cross-related terms and modified equations of General Relativity and Quantum Mechanics. To address the “background problem”, a metric tensor is introduced into stationary Schrödinger equations via curved coordinates yielding quantum spacetime variation term. Then quantum Lagrangian is added to Einstein-Hilbert functional yielding quantum stress-energy tensor. Obtained from one variational principle, two theories are linked by a common quantum spacetime field. The theory offers some interpretations of the quantum vacuum spacetime fluctuations, zero-point-fields, quantum fields shifting towards high spacetime densities, the quantum nature of spacetime, and black hole singularity.
文摘In this work, we make a number of proposals to explain how a world of (4 + 4)-dimensions can be useful for a better understanding of both dark matter and quantum gravity. The key idea is to look for some advantage of considering self-dual invariants in (4 + 4)-dimensions rather than in a separate context of (1 + 3)-dimensions or (3 + 1)-dimensions. In fact, we show that by considering the duality concept in (4 + 4)-dimensions we may provide an alternative meaning of a framework for loop quantum gravity. Moreover, considering the Dirac equation in (4 + 4)-dimensions for a particle without electric charge and mass, we show that when it is projected into the (1 + 3) and (3 + 1)-worlds may describe a system with electric charge and mass. We also discuss the relation between the three physical scenarios;(4 + 4)-world, black-holes and dark matter.
文摘It is reasonably expected 1) that a theory of quantum gravity will unify the extremes of scale currently described by General Relativity and quantum mechanics, and 2) that black holes are the crucible from which a theory of quantum gravity will emerge. In perspective, we already have a mechanism that links the local, macroscopic frame with the remote, apparently microscopic frame. A simple mathematical principle acts as a limit on D(n), suggesting a “maximum physical reality”, and that effects which are clearly perspectival at D=3 become “more real” (effectively observer-independent) with each D(n) increment. The model suggests alternative interpretations of gravitation and the quantum, entanglement, space, the Standard Model of particles and interactions, black holes, the measurement problem and the information paradox.
文摘A theory of Quantum Gravity based on Primordial Field Theory is applied to a fundamental particle, the neutron. The result is compared to the current quantum description of the neutron bouncing in a gravitational field. Our quantum gravity theory yields results in agreement with the Q-bounce experimental data, but ontologically different from quantum mechanics. The differences are summarized and imply that this experiment on a fundamental particle has the potential to radically alter the ontology of field theory.
文摘This article gives an elementary account of the recently proposed theory of spontaneous quantum gravity. It is argued that a viable quantum theory of gravity should be falsifiable, and hence it should dynamically explain the observed absence of quantum superpositions of space-time geometries in its classical limit.
文摘Quantum gravitational theory, based on the hypothesis of the absolute reference system, reveals the function of the effects of the gravitational field at the microscopic and macroscopic scale. The quantum nature of gravitational potential, and the dynamics and kinetic energy of photons and elementary particles under the influence of the gravitational field are studied, and a quantum interpretation of gravitational redshift is given. There is also a complete agreement of this quantum gravitational theory with the existing experimental data.
文摘We present a simple way to approach the hard problem of quantization of the gravitational field in four-dimensional space-time, due to non-linearity of the Einstein equations. The difficulty may be overcome when the cosmological constant is non-null. Treating the cosmological contribution as the energy-momentum of vacuum, and representing the metric tensor onto the tetrad of its eigenvectors, the corresponding energy-momentum and, consequently, the Hamiltonian are easily quantized assuming a correspondence rule according to which the eigenvectors are replaced by creation and annihilation operators for the gravitational field. So the geometric Einstein tensor, which is opposite in sign respect to the vacuum energy-momentum (plus the possible known matter one), is also quantized. Physical examples provided by Schwarzschild-De Sitter, Robertson-Walker-De Sitter and Kerr-De Sitter solutions are examined.
文摘Attempts to unify Gravity Theory and Quantum Field Theory (QFT) under Loop Quantum Gravity Theory (LQG), are diverse;a dividing line between classical and quantum is sought with Schrödinger cat-state experiments. A Primordial Field Theory-based alternative is presented, and a gravity-based harmonic oscillator developed. With quantum theory applied at micro-scales and gravity theory at meso- and macro-scales, this scale-gap contributes to the conceptual problems associated with Loop Quantum Gravity. Primordial field theory, spanning all scales, is used to conceptually stretch key ideas across this gap. An LQG interpretation of the wave function associated with the oscillator is explained.
基金financial support provided under the Chilean FONDECYT(3170035)
文摘This study set out to investigate charged vector particles tunneling via horizons of a pair of accelerating rotating charged NUT black holes under the influence of quantum gravity.To this end,we use the modified Proca equation incorporating generalized uncertainty principle.Applying the WKB approximation to the field equation,we obtain a modified tunneling rate and the corresponding corrected Hawking temperature for this black hole.Moreover,we analyze the graphical behavior of the corrected Hawking temperature T'_H with respect to the event horizon for the given black hole.By considering quantum gravitational effects on Hawking temperatures,we discuss the stability analysis of this black hole.For a pair of black holes,the temperature T'_H increases with the increase in rotation parameters a andω,correction parameterβ,black hole acceleration a,and arbitrary parameter k,and decreases with the increase in electric e and magnetic charges g.
基金supported by the National Natural Science Foundation of China (Grant Nos.11875006,and 11961131013)the support by the Polish Narodowe Centrum Nauki (Grant No.2018/30/Q/ST2/00811)。
文摘The quasi-local notion of an isolated horizon is employed to study the entropy of black holes without any particular symmetry in loop quantum gravity. The idea of characterizing the shape of a horizon by a sequence of local areas is successfully applied in the scheme to calculate the entropy by the S O(1, 1) BF boundary theory matching loop quantum gravity in the bulk. The generating function for calculating the microscopical degrees of freedom of a given isolated horizon is obtained. Numerical computations of small black holes indicate a new entropy formula containing the quantum correction related to the partition of the horizon. Further evidence shows that, for a given horizon area, the entropy decreases as a black hole deviates from the spherically symmetric one,and the entropy formula is also well suitable for big black holes.
