Convergence of combinatorial gravity

Kelly, Christy; Trugenberger, Carlo A.; Biancalana, Fabio

doi:10.1103/physrevd.105.124002

Cited by 6 publications

(11 citation statements)

References 81 publications

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“…4). From these detector arrays and this white incident neutron beam, Chi-Nu experiments have published results for the PFNS of 239 Pu and 235 U [8][9][10], with 238 U and 240 Pu results forthcoming.…”

Section: Methodsmentioning

confidence: 99%

“…In Fig. 4, we report for the first time a calculation of not just a single covariance matrix for all data points of a single PFNS measurement, but a single matrix describing correlations between all data points of all published Chi-Nu PFNS measurements [9,10]. Data point number, along both the x and y axes, is an index for outgoing neutron energy points of a PFNS result.…”

Section: Correlations Between Pfns Data Points Across Target Nucleimentioning

confidence: 99%

“…Data points 1-1300 on each axis correspond to the 239 Pu results, and data points 1301-2600 correspond to 235 U. Thus, while the matrix from x = 1-1300 and y = 1-1300 corresponds to the published 239 Pu correlation matrix [9] and the matrix from x = 1301-2600 and y = 1302-2600 corresponds to 235 U [10], the off-diagonal blocks (i.e., x = 1-1300 and y = 1301-2600, and its reflection over the line x = y) describes the correlations between 239 Pu and 235 U PFNS results from the Chi-Nu experiment. These correlations arise primarily from the similarities in the MCNP simulations used for analysis, since the simulations differ only in target nucleus identity and orientation of the PPAC target chamber.…”

Section: Correlations Between Pfns Data Points Across Target Nucleimentioning

confidence: 99%

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The Covariance of PFNS Results from the Chi-Nu Experiment

Kelly

O’Donnell²,

Devlin³

2023

EPJ Web Conf.

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The prompt fission neutron spectrum (PFNS) from neutron-induced fission is a fundamental quantity for the behavior of nuclear reactors, and has been measured many times on a wide variety of nuclei and covering different ranges of incident and emitted neutron energies. However, results from past measurements are frequently called into question in modern nuclear data evaluations because of a lack of thorough experimental documentation and incomplete uncertainty analyses. The Chi-Nu experiment at Los Alamos National Laboratory was designed to produce high-precision measurements of the PFNS of major actinides over a wide range of incident and emitted neutron energies, and with the documentation and covariance analysis required to ensure that the results of this experiment maintain their impact long into the future, thereby avoiding this pitfall of past measurements. In this work we describe the Chi-Nu experiment along with summaries of the treatment of and methods developed to address two important components of the analysis of Chi-Nu data: random-coincidence backgrounds and MCNP simulations. Furthermore, we describe the first results for correlations not just between all data points collected on a single target nucleus, but also between all data points from separate Chi-Nu measurements on 235U and 239Pu. These correlations are important for accurately calculating ratios of the PFNS from one actinide to another, which are rare and can be informative for nuclear data evaluation efforts.

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Section: Methodsmentioning

confidence: 99%

Section: Correlations Between Pfns Data Points Across Target Nucleimentioning

confidence: 99%

Section: Correlations Between Pfns Data Points Across Target Nucleimentioning

confidence: 99%

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The Covariance of PFNS Results from the Chi-Nu Experiment

Kelly

O’Donnell²,

Devlin³

2023

EPJ Web Conf.

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“…Indeed, the field of discrete geometry has advanced by leaps and bounds in recent years. The Ollivier curvature is not the only measure of discrete combinatorial curvature that has been proposed, but it is the only one that has been shown to converge to the continuum Ricci curvature for geometric random graphs defined on manifolds [32,33] (see [34] for its relation to Forman curvature [35]), although a recent result claims a sectional graph measure that also converges [36] to its continuum counterpart. The Ollivier curvature is unfortunately cumbersome to compute with, in the general case.…”

Section: Introductionmentioning

confidence: 99%

Combinatorial Quantum Gravity and Emergent 3D Quantum Behaviour

Trugenberger

2023

Universe

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We review combinatorial quantum gravity, an approach that combines Einstein’s idea of dynamical geometry with Wheeler’s “it from bit” hypothesis in a model of dynamical graphs governed by the coarse Ollivier–Ricci curvature. This drives a continuous phase transition from a random to a geometric phase due to a condensation of loops on the graph. In the 2D case, the geometric phase describes negative-curvature surfaces with two inversely related scales: an ultraviolet (UV) Planck length and an infrared (IR) radius of curvature. Below the Planck scale, the random bit character survives; chunks of random bits of the Planck size describe matter particles of excitation energy given by their excess curvature. Between the Planck length and the curvature radius, the surface is smooth, with spectral and Hausdorff dimension 2. At scales larger than the curvature radius, particles see the surface as an effective Lorentzian de Sitter surface, the spectral dimension becomes 3, and the effective slow dynamics of particles, as seen by co-moving observers, emerges as quantum mechanics in Euclidean 3D space. Since the 3D distances are inherited from the underlying 2D de Sitter surface, we obtain curved trajectories around massive particles also in 3D, representing the large-scale gravity interactions. We thus propose that this 2D model describes a generic holographic screen relevant for real quantum gravity.

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“…3. Preliminary results for inelastic scattering cross sections on 12 C, 27 Al, and 56 Fe are shown in Sec. 4.…”

Section: Introductionmentioning

confidence: 99%

The Neutron Scattering Cross Section and Angular Distribution Measurement Program at LANL

et al. 2023

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Neutron scattering cross sections and angular distributions are leading terms in descriptions of neutron transport through any system. Despite the fundamental importance of nuclear data on these quantities, significant gaps in understanding and lack of experimental data persist in heavier elements and down to lighter structural materials, such as iron and aluminum. Recent measurements on carbon have also shown definitive proof that the neutron angular distribution can change with respect to the emission angle of γ-rays from inelastic scattering, thereby complicating γ-tagged measurements of inelastic neutron scattering. In this work, we describe the emerging program at Los Alamos National Laboratory for measurements of neutron scattering cross sections and neutron, γ-ray, and correlated n-γ angular distributions utilizing liquid scintillator detectors and the Correlated Gamma-Neutron Array for Scattering (CoGNAC) of CLYC scintillators. Currently, these detectors are operated simultaneously with the in-progress array of CLYC detectors in an inverted position, and data analysis techniques are being developed to span scattering measurements from light nuclei up through actinides. Preliminary results for measurements on 12C, 27Al, and 56Fe are presented here with a description of the analysis methods applied and anticipated capabilities of the full-scale detection system.

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Convergence of combinatorial gravity

Cited by 6 publications

References 81 publications

The Covariance of PFNS Results from the Chi-Nu Experiment

The Covariance of PFNS Results from the Chi-Nu Experiment

Combinatorial Quantum Gravity and Emergent 3D Quantum Behaviour

The Neutron Scattering Cross Section and Angular Distribution Measurement Program at LANL

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