Topological features of the quantum vacuum

Alexander, Stephon; Carballo-Rubio, Raúl

doi:10.1103/physrevd.101.024058

Cited by 19 publications

(32 citation statements)

References 68 publications

(90 reference statements)

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“…Two natural directions to consider are a modification to the general theory of relativity, such as BF coupled [82][83][84] or Chern-Simons gravity [85,86], or alternatives to cold non-interactive dark matter. In the context of this paper, we will focus on the latter.…”

Section: A Dark Matter Substructurementioning

confidence: 99%

Domain Adaptation for Simulation-Based Dark Matter Searches Using Strong Gravitational Lensing

Alexander¹,

Gleyzer²,

Reddy³

et al. 2021

Preprint

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Clues to the identity of dark matter have remained surprisingly elusive, given the scope of experimental programs aimed at its identification. While terrestrial experiments may be able to nail down a model, an alternative, and equally promising, method is to identify dark matter based on astrophysical or cosmological signatures. A particularly sensitive approach is based on the unique signature of dark matter substructure on galaxy-galaxy strong lensing images. Machine learning applications have been explored in detail for extracting just this signal. With limited availability of high quality strong lensing data, these approaches have exclusively relied on simulations. Naturally, due to the differences with the real instrumental data, machine learning models trained on simulations are expected to lose accuracy when applied to real data. This is where domain adaptation can serve as a crucial bridge between simulations and real data applications. In this work, we demonstrate the power of domain adaptation techniques applied to strong gravitational lensing data with dark matter substructure. We show with simulated data sets of varying complexity, that domain adaptation can significantly mitigate the losses in the model performance. This technique can help domain experts build and apply better machine learning models for extracting useful information from strong gravitational lensing data expected from the upcoming surveys.

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Section: A Dark Matter Substructurementioning

confidence: 99%

Domain Adaptation for Simulation-Based Dark Matter Searches Using Strong Gravitational Lensing

Alexander¹,

Gleyzer²,

Reddy³

et al. 2021

Preprint

Self Cite

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“…Here we review a model presented in [21] and developed further in [22] that will provide the background for our analysis. This model couples Einstein gravity to a topological field theory (BF theory) such that the volume form determined by the spacetime metric is constrained to be equal to a volume form constructed from one of the fields of the BF theory.…”

Section: Review Of Bf-coupled Gravitymentioning

confidence: 99%

“…As proposed in [21,22], we consider a theory of gravity in four spacetime dimensions obtained by replacing the "cosmological constant" µ in the BF action with the usual Lagrangian of Einstein gravity written in terms of a composite metric ĝµν , which we define below. The action of the theory is 1…”

Section: B Bf-coupled Gravitymentioning

confidence: 99%

“…Given these discrepancies, now is an auspicious time to consider modifications of general relativity and the standard model that have the potential to resolve both issues. In this paper, we will focus on the first possibility by further developing a recently proposed modification of general relativity that draws on topological field theory to resolve aspects of the cosmological constant problem [21,22]. Here, we explore a natural extension of this theory that has dramatic implications for cosmological dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Black hole and cosmological analysis of BF sequestered gravity

Alexander,

Clark,

Herczeg

et al. 2021

Preprint

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We study a minimal extension of a recently proposed modification of general relativity that draws on concepts from topological field theory to resolve aspects of the cosmological constant problem. In the original model, the field content of general relativity was augmented to include a gauge field and an adjoint-valued two-form without modifying the classical gravitational dynamics. Here we include a kinetic term for the gauge field which sources fluctuations of the cosmological constant. We then study spherically symmetric black holes and a simple homogeneous, isotropic cosmological model predicted by the extended theory. For the black hole case, we observe deviations near the event horizon as well as a "charge"-like behavior induced by the gauge field. In the cosmological case, Ḣ is always positive and some solutions asymptote to a constant H.

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“…Alternatively, there are many non-supersymmetric ideas that may bear fruit with a merger of T W gravity [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Dark energy from dynamical projective connections

Brensinger

Heitritter

Rodgers

et al. 2020

Class. Quantum Grav.

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We further develop the gravitational model, Thomas-Whitehead Gravity (TW Gravity), that arises when projective connections become dynamical fields. TW Gravity has its origins in geometric actions from string theory where the TW projective connection appears as a rank two tensor, D ab , on the spacetime manifold. Using a Gauss-Bonnet (GB) action built from the (d + 1)-dimensional TW connection, and applying the tensor decomposition D ab = D ab +4Λ/(d(d−1))g ab , we arrive at a gravitational model made up of a d-dimensional Einstein-Hilbert + GB action sourced by D ab and with cosmological constant Λ. The d = 4 action is studied and we find that Λ ∝ 1/J 0 , with J 0 the coupling constant for D ab .For Λ equal to the current measured value, J 0 is on the order of the measured angular momentum of the observable Universe. We view this as Λ controlling the scale of patches of the Universe that acquire angular momentum, with the net angular momentum of multiple patches vanishing, as required by the cosmological principle. We further find a universal axial scalar coupling to all fermions where the trace, D = D ab g ab acts as the scalar. This suggests that D is also a dark matter portal for non-standard model fermions.Here we review the cosmological constant problem and our proposed method to investigate solutions via T W gravity [6]. A more complete review of the cosmological constant problem is given in [21]. In appendix B, we summarize general relativity and cosmology in a Friedmann-Lemaitre-Robertson-Walker background, describing the calculation of the cosmological constant using current data. The simplest description of 6 The discrepancy between Eqs. (2.1) and (2.2) is more precisely 121 orders of magnitude. Taking instead Λ to be proportional to the reduced Planck mass squared Λ ∼ M 2 P l c 3 / ∼ 10 68 m −2 where the reduced Planck mass is M P l = c/(8πG) ≈ 4.341 × 10 −9 kg results in a 120 order of magnitude discrepancy from Eq. (2.2).

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Topological features of the quantum vacuum

Cited by 19 publications

References 68 publications

Domain Adaptation for Simulation-Based Dark Matter Searches Using Strong Gravitational Lensing

Domain Adaptation for Simulation-Based Dark Matter Searches Using Strong Gravitational Lensing

Black hole and cosmological analysis of BF sequestered gravity

Dark energy from dynamical projective connections

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