Research Laboratory of Electronics Quarterly progress report, period ending 31 Aug. 1966
Research reports in theoretical physics, plasma dynamics, spectroscopy, radio astronomy, and communication sciences and engineering
COMMUNICATION THEORY↗
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Using Boosted Decision Trees to Select High Quality Measurements in the Mu2e Experiment at Fermilab
This thesis presents the implementation and evaluation of a Boosted Decision Tree (BDT) model to improve the selection of high-quality track measurements in the Mu2e experiment at Fermilab. The Mu2e experiment is a high-energy physics experiments seeking to observe a rare theoretical physics process known as Charged Lepton Flavor Violation. A significant challenge faced by the Mu2e experiment are so-called background events, which are events whose data mimics that of the rare physics process the experiment seeks to observe. Without a mechanism to reduce background, it would be impossible to know whether Charged Lepton Flavor Violation occurred or not. To this end, high-quality track measurements must be distinguished from low-quality track measurements. A track can be conceived of as the reconstructed path of a particle that traveled through the Mu2e detector. In addition to other data, data about such tracks is stored using a C++-based framework, specific to the domain of high-energy physics, known as ROOT. A boosted decision tree model was trained using ROOT’s Toolkit For Multivariate Analysis by leveraging variables ancillary to track quality. In evaluation, the BDT achieves a ROC-AUC of 0.927 in discriminating good-quality tracks from poor-quality tracks. Such a score is indicative of both strong discrimination and strong generalization. Subsequently, it is shown that applying a BDT-based quality cut to the distribution of particle momenta significantly enhances the signal-to-background distinction for signal electrons, paving the way for improved sensitivity to Charged Lepton Flavor Violation.
Mullany, Brendan T. [Drew U.] (ORCID:0009000818888↗
Inferring three-nucleon couplings from multi-messenger neutron-star observations
Understanding the interactions between nucleons in dense matter is an important challenge in theoretical physics. Effective field theories have emerged as the dominant approach to address this problem at low energies, with many successful applications to the structure of nuclei and the properties of dense nucleonic matter. However, how far into the interior of neutron stars these interactions can describe dense matter is an open question. Here, we develop a framework that enables the inference of three-nucleon couplings in dense matter directly from astrophysical neutron star observations. We apply this formalism to the LIGO/Virgo gravitational-wave event GW170817 and the X-ray measurements from NASA’s Neutron Star Interior Composition Explorer and establish direct constraints for the couplings that govern three-nucleon interactions in chiral effective field theory. Furthermore, we demonstrate how next-generation observations of a population of neutron star mergers can offer stringent constraints on three-nucleon couplings, potentially at a level comparable to those from laboratory data. Our work directly connects the microscopic couplings in quantum field theories to macroscopic observations of neutron stars, providing a way to test the consistency between low-energy couplings inferred from terrestrial and astrophysical data.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
SU(n) and Quantum SU(n) Symmetries in Physical Systems [Slides]
Presence of SU(n) or other Lie group symmetry in a physical system is its powerful, usually underutilized property. In many cases it allows for finding analytical solutions to nonlinear differential equations describing this system. Power of the method is presented on diversified examples from mathematical physics: Lie-group symmetries in finding solutions of generalized, multidimensional theory of gravity; analytical Dirac–equation solutions for description of conducting polymers; stability of qubit states in quantum computers; spatial defects in condensed matter; reconstruction of 3D object from its 2D tomographic image; significant improvement of numerical solutions stability for Euler equations. The next question after obtaining such Lie group symmetric solution is: does a generalized solution with appropriate quantum group symmetry exists for the given physical system, and if yes what is the physical meaning of the deformation parameter q introduced by such solution. In many cases it can be identified. Any SU(n) solution is by its nature singular, assuming a perfect symmetry of the physical system discussed. Such solution gives a powerful insight to theoretical physics, yet the assumption may be too demanding for experimental applications. Deformation parameter q from a quantum group symmetry allows for a continuum of solutions, more applicable to experiments.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Astronomers Travel in Time and Space with Light
This is an excerpt of John Mather's in a book titled: INSPIRED BY LIGHT, Reflections from the International Year of Light 2015. It was produced in January 2016 by SPIE, the European Physical Society (EPS), and The Abdus Salam International Centre for Theoretical Physics (ICTP) to commemorate the International Year of Light and Light-based Technologies 2015. The excerpt discusses how astronomers use light.
space↗
Theoretical Problems in Materials Science
Interactions between theoretical physics and material sciences to identify problems of common interest in which some of the powerful theoretical approaches developed for other branches of physics may be applied to problems in materials science are presented. A unique structure was identified in rapidly quenched Al-14% Mn. The material has long-range directed bonds with icosahedral symmetry which does not form a regular structure but instead forms an amorphous-like quasiperiodic structure. Finite volume fractions of second phase material is advanced and is coupled with nucleation theory to describe the formation and structure of precipitating phases in alloys. Application of the theory of pattern formation to the problem of dendrite formation is studied.
Langer, J. S.↗
Summary of the activity in plasma physics at the University of Iowa Annual status report, Jun. 1970 - Jun. 1971
Annotated bibliography of theoretical physics, magnetohydrodynamics of ionosphere and magnetosphere
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Kristian Birkeland - The man and the scientist
A review is presented of Birkeland's outstanding contributions to auroral theory and, in particular, to the foundation of modern magnetospheric physics. Birkeland's first years in research, after a study of mathematics and theoretical physics at the university, were concerned with Maxwell's theory, the investigation of electromagnetic waves in conductors, wave propagation in space, an energy transfer by means of electromagnetic waves, and a general expression for the Poynting vector. Experiments with cathode rays near a magnet in 1895, led Birkeland to the development of an auroral theory. This theory represented the first detailed, realistic explanation of the creation of an aurora. Attention is given to experiments conducted to verify the theory, the discovery of the polar elementary storm, and the deduction of auroral electric currents. Birkeland's background and education is also considered along with his personality.
Egeland, A.↗
Two-loop contributions of axion-like particles to electromagnetic and chromomagnetic form factors
Abstract Axions and axion-like particles emerge in many models for physics beyond the Standard Model. Thus, they have gained increasing research interest in both experimental and theoretical physics apart from their original proposition as a solution to the strong CP -problem. Among other aspects it has recently been shown that ALPs can potentially provide a solution to the long-lasting discrepancy between theory and experiment of the anomalous magnetic moment of the muon. Provided that the ALP has flavor-violating couplings to leptons, they can also mediate flavor-violating decays like $$\mu \rightarrow e\gamma $$ μ → e γ . Both processes are mediated through related form factors that we compute to two-loop order. We further show numerical implications of our calculations and how they might affect constraints on ALP couplings derived from experiments.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Problems of theoretical seismology and physics of the earth's interior <voprosy teoreticheskoi seismologii i fiziki zemnykh nedr<
Theoretical seismology and physics of earth core and mantle
SEISMOLOGY↗
Theoretical and Experimental Beam Plasma Physics (TEBPP)
The theoretical and experimental beam plasma physics (TEBPP) consists of a package of five instruments to measure electric and magnetic fields, plasma density and temperature, neutral density, photometric emissions, and energetic particle spectra during firings of the particle injector (SEPAC) electron beam. The package is deployed on a maneuverable boom (or RMS) and is used to measure beam characteristics and induced perturbations in the near field ( 10 m) and mid field (10 m to 100 m) along the electron beam. The TEBPP package will be designed to investigate induced oscillations and induced electromagnetic mode waves, neutral and ion density and temperature effects, and beam characteristics as a function of axial distance.
Roberts, W. T.↗
Theoretical and Experimental Beam Plasma Physics (TEBPP)
The theoretical and experimental beam plasma physics (TEBPP) consists of a package of five instruments to measure electric and magnetic fields, plasma density and temperature, neutral density, photometric emissions, and energetic particle spectra during firings of the particle injector (SEPAC) electron beam. The package is developed on a maneuverable boom (or RMS) and is used to measure beam characteristics and induced perturbations field ( 10 m) and mid field ( 10 m to 100 m) along the electron beam. The TEBPP package will be designed to investigate induced oscillations and induced electromagnetic mode waves, neutral and ion density and temperature effects, and beam characteristics as a function of axial distance.
Roberts, B.↗
Forces and Motion: Dynamics of the Tethered Satellite
In this 'Lift off to Learning' series, Loren Shriver, commander of STS 46, and the other members of the mission (Claude Nicollier, Marsha Ivins, Andrew Allen, Jeffrey Hoffman, Franklin Chiang-Diaz, and Franco Maerba) use computer graphics, and physical experiments to explain how the tethered satellite to be deployed during their mission will be raised, how it works, the influence of the Shuttle on the satellite and the satellite's influence on the Shuttle's orbit, the gravitational effects, and other effects concerning the Theoretical Physics used to plan this mission (gravity gradient force, center of mass, angular momentum, centrifugal force, and coriolis effect). This video ends with a discussion of the technology transfer and utilization of this tethered satellite concept and design.
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Advanced Propulsion Physics Lab: Eagleworks Investigations
Eagleworks Laboratory is an advanced propulsions physics laboratory with two primary investigations currently underway. The first is a Quantum Vacuum Plasma Thruster (QVPT or Q-thrusters), an advanced electric propulsion technology in the development and demonstration phase. The second investigation is in Warp Field Interferometry (WFI). This is an investigation of Dr. Harold "Sonny" White's theoretical physics models for warp field equations using optical experiments in the Electro Optical laboratory (EOL) at Johnson Space Center. These investigations are pursuing technology necessary to enable human exploration of the solar system and beyond.
Scogin, Tyler↗
AI for nuclear physics: the EXCLAIM project
An overview of the recent activity of the newly funded EXCLusives with AI and Machine learning (EXCLAIM) collaboration is presented. The main goal of the collaboration is to develop a framework to implement AI and machine learning techniques in problems emerging from the phenomenology of high energy exclusive scattering processes from nucleons and nuclei, maximizing the information that can be extracted from various sets of experimental data, while implementing theoretical constraints from lattice QCD. A specific perspective embraced by EXCLAIM is to use the methods of theoretical physics to understand the working of ML, beyond its standardized applications to physics analyses which most often rely on industrially provided tools, in an automated way.
Analysis and statistical methods↗
Tribute to José N. Onuchic
This Festschrift Virtual Special Issue in The Journal of Physical Chemistry B is dedicated to the scientific contributions of Prof. José Nelson Onuchic. It serves as a celebration of his years of service, mentorship, and leadership to the biological physics, theoretical chemistry, and computational biology communities. This collection of more than 60 articles has been compiled from an extensive network of scientists that have, in distinct ways, been impacted by the scientific legacy of Prof. Onuchic. It is a written testament to how his work has influenced many areas related to the physics and chemistry of biological systems. In conclusion, this Festschrift provides a good sample of the areas in that Professor Onuchic has had a direct impact via collaboration, mentorship, and scientific dissemination of his research.
99 GENERAL AND MISCELLANEOUS↗
Internal structure and properties of Mars
Theoretical physical models of the Martian interior are presented in the light of recent and revised data and constraints. These models include thermal evolution, densities, and seismic-wave velocities. The interior of Mars appears to be earthlike in many respects. Although thermal models indicate that Mars has passed its peak of evolution, it may still have an asthenosphere and may be moderately active tectonically. Mars has an Fe-FeS core with a radius of 1500-2000 km. The mantle is enriched in FeO with an olivine composition of about Fo75. Theoretically determined seismic-wave velocities are relatively well constrained in the mantle, with upper-mantle P-wave velocities ranging from 7.64 to 7.80 km/sec. However, there are wide variations in P-wave velocity in the core, dependent on composition. The shadow zone due to the core is larger than earth's.
Johnston, D. H.↗
Trilogy, A Planetary Geodesy Mission Concept for Measuring the Expansion of the Solar System
The scale of the solar system is slowly changing, likely increasing as a result of solar mass loss, with additional change possible if there is a secular variation of the gravitational constant, G. The measurement of the change of scale could provide insight into the past and the future of the solar system, and in addition a better understanding of planetary motion and fundamental physics. Estimates for the expansion of the scale of the solar system are of order 1.5 cm year(exp -1) AU(exp -1), which over several years is an observable quantity with present-day laser ranging systems. This estimate suggests that laser measurements between planets could provide an accurate estimate of the solar system expansion rate. We examine distance measurements between three bodies in the inner solar system -- Earth's Moon, Mars and Venus -- and outline a mission concept for making the measurements. The concept involves placing spacecraft that carry laser ranging transponders in orbit around each body and measuring the distances between the three spacecraft over a period of several years. The analysis of these range measurements would allow the co-estimation of the spacecraft orbit, planetary ephemerides, other geophysical parameters related to the constitution and dynamics of the central bodies, and key geodetic parameters related to the solar system expansion, the Sun, and theoretical physics.
David E Smith↗