Non-metric construction of spacetime defects

Queiruga, Jose M.

doi:10.48550/arxiv.1912.10296

Cited by 2 publications

(2 citation statements)

References 26 publications

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“…Some of these works put forward that gravity theories with non-metricity can avoid the spacetime singularities present in GR already at a classical level [81,82]. It has also been suggested that non-Riemannian geometries could be successful in being a low-energy effective description of theories of quantum gravity, as they could be more suited in accounting for features of a quantum-spacetime that may exist at high energies [63,[83][84][85][86]. Hence, that the existence of non-metricity should be experimentally probed at different energy scales.…”

Section: Introductionmentioning

confidence: 99%

Minimal coupling in presence of non-metricity and torsion

Delhom

2020

Eur. Phys. J. C

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We deal with the question of what it means to define a minimal coupling prescription in presence of torsion and/or non-metricity, carefully explaining while the naive substitution $$\partial \rightarrow \nabla $$∂→∇ introduces extra couplings between the matter fields and the connection that can be regarded as non-minimal in presence of torsion and/or non-metricity. We will also investigate whether minimal coupling prescriptions at the level of the action (MCPL) or at the level of field equations (MCPF) lead to different dynamics. To that end, we will first write the Euler–Lagrange equations for matter fields in terms of the covariant derivatives of a general non-Riemannian space, and derivate the form of the associated Noether currents and charges. Then we will see that if the minimal coupling prescriptions is applied as we discuss, for spin 0 and 1 fields the results of MCPL and MCPF are equivalent, while for spin 1/2 fields there is a difference if one applies the MCPF or the MCPL, since the former leads to charge violation.

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Section: Introductionmentioning

confidence: 99%

Minimal coupling in presence of non-metricity and torsion

Delhom

2020

Eur. Phys. J. C

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“…Some of these works put forward that gravity theories with non-metricity can avoid the spacetime singularities present in GR already at a classical level [70,71]. It has also been suggested that non-Riemannian geometries could be successful in being a low-energy effective description of theories of quantum gravity, as they could be more suited in accounting for features of a quantum-spacetime that may exist at high energies [61,[72][73][74][75]. This makes clear that the existence of non-metricity should be experimentally tested at different energy scales.…”

Section: Introductionmentioning

confidence: 99%

Minimal coupling in presence of non-metricity and torsion

Delhom

2020

Preprint

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We deal with the question of what are and what are not minimal coupling prescriptions in presence of torsion and/or non-metricity, carefully explaining while the naive substitution ∂ → ∇ is not actually a minimal coupling prescritpion. We will also investigate whether minimal coupling prescriptions at the level of the action (MCPL) or at the level of field equations (MCP) lead to different dynamics. To that end, we will first write the Euler-Lagrange equations for matter fields in terms of the covariant derivatives of a general non-Riemannian space, and derivate the form of the associated Noether currents and charges. Then we will see that, if the correct minimal coupling prescriptions is applied, for spin 0 and 1 fields the results of MCPL and MCP are equivalent, while for spin 1/2 fields there is a difference if one applies the MCP or the MCPL, since the former leads to charge violation. We will also explicitly show how the usual naive substitution ∂ → ∇ is not a minimal coupling prescription for spin 0, 1/2 and 1 fields in presence of torsion and/or non-metricity.1 Here we use Riemannian to imply that the connection is metric-compatible, and non-Riemannian for otherwise. Notice that Mathematicians have another meaning for Riemannian, which is related to the signature of the metric. Our metrics will be assumed to have Lorentzian signature.

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Non-metric construction of spacetime defects

Abstract: We describe a spacetime endowed with a non-metricity tensor which effectively serves as a model of a spacetime foam. We explore the consequences of the non-metricity in several f (R) theories.

Cited by 2 publications

References 26 publications

Minimal coupling in presence of non-metricity and torsion

Minimal coupling in presence of non-metricity and torsion

Minimal coupling in presence of non-metricity and torsion

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