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Articles 1 - 30 of 542

Full-Text Articles in Physics

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa Oct 2019

Analog Implementation Of The Hodgkin-Huxley Model Neuron, Zachary D. Mobille, George H. Rutherford, Jordan Brandt-Trainer, Rosangela Follmann, Epaminondas Rosa

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft Oct 2019

Period Drift In A Neutrally Stable Stochastic Oscillator, Kevin Sanft

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


If Space-Time Is Discrete, We May Be Able To Solve Np-Hard Problems In Polynomial Time, Ricardo Alvarez, Nick Sims, Christian Servin, Martine Ceberio, Vladik Kreinovich Aug 2019

If Space-Time Is Discrete, We May Be Able To Solve Np-Hard Problems In Polynomial Time, Ricardo Alvarez, Nick Sims, Christian Servin, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

Traditional physics assumes that space and time are continuous. However, this reasonable model leads to some serious problems. One the approaches that physicists follow to solve these problems is to assume that the space-time is actually discrete. In this paper, we analyze possible computational consequences of this discreteness. It turns out that in a discrete space-time, we may be able to solve NP-hard problems in polynomial time.


Avoiding Einstein-Podolsky-Rosen (Epr) Paradox: Towards A More Physically Adequate Description Of A Quantum State, Joseph Bernal, Olga Kosheleva, Vladik Kreinovich Aug 2019

Avoiding Einstein-Podolsky-Rosen (Epr) Paradox: Towards A More Physically Adequate Description Of A Quantum State, Joseph Bernal, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

The famous EPR paradox shows that if we describe quantum particles in the usual way -- by their wave functions -- then we get the following seeming contradiction. If we entangle the states of the two particles, then move them far away from each other, and measure the state of the first particle, then the state of the second particle immediately changes -- which contradicts to special relativity, according to which such immediate-action-at-a-distance is not possible. It is known that, from the physical viewpoint, this is not a real paradox: if we measure any property of the second particle, the results will not ...


Introduction To Classical Field Theory, Charles G. Torre Aug 2019

Introduction To Classical Field Theory, Charles G. Torre

All Complete Monographs

This is an introduction to classical field theory. Topics treated include: Klein-Gordon field, electromagnetic field, scalar electrodynamics, Dirac field, Yang-Mills field, gravitational field, Noether theorems relating symmetries and conservation laws, spontaneous symmetry breaking, Lagrangian and Hamiltonian formalisms.


Neutron Lifetime Puzzle And Nuclear Stability: A Possible Relation, Olga Kosheleva, Vladik Kreinovich Jul 2019

Neutron Lifetime Puzzle And Nuclear Stability: A Possible Relation, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

It is known that a free neutron decays into a proton, an electron, and an anti-neutrino. Interesting, recent attempts to measure the neutron's lifetime has led to two slightly different estimates: namely, the number of decaying neutrons is somewhat larger than the number of newly created protons. This difference is known as the neutron lifetime puzzle. A natural explanation for this difference is that in some cases, a neutron decays not into a proton, but into some other particle. If this explanation is true, this implies that nuclei with a sufficiently large number of neutrons will be unstable. Based ...


Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan Jul 2019

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and ...


Rare Event Sampling In Applied Stochastic Dynamical Systems, Yiming Yu May 2019

Rare Event Sampling In Applied Stochastic Dynamical Systems, Yiming Yu

Dissertations

Predicting rare events is a challenging problem in many complex systems arising in physics, chemistry, biology, and materials science. Simulating rare events is often prohibitive in such systems due to their high dimensionality and the numerical cost of their simulation, yet analytical expressions for rare event probabilities are usually not available. This dissertation tackles the problem of approximation of the probability of rare catastrophic events in optical communication systems and spin-torque magnetic nanodevices. With the application of the geometric minimum action method, the probability of pulse position shifts or other parameter changes in a model of an actively mode-locked laser ...


Pairwise Completely Positive Matrices And Conjugate Local Diagonal Unitary Invariant Quantum States, Nathaniel Johnston, Olivia Maclean May 2019

Pairwise Completely Positive Matrices And Conjugate Local Diagonal Unitary Invariant Quantum States, Nathaniel Johnston, Olivia Maclean

Electronic Journal of Linear Algebra

A generalization of the set of completely positive matrices called pairwise completely positive (PCP) matrices is introduced. These are pairs of matrices that share a joint decomposition so that one of them is necessarily positive semidefinite while the other one is necessarily entrywise non-negative. Basic properties of these matrix pairs are explored and several testable necessary and sufficient conditions are developed to help determine whether or not a pair is PCP. A connection with quantum entanglement is established by showing that determining whether or not a pair of matrices is pairwise completely positive is equivalent to determining whether or not ...


Quantifying Complex Systems Via Computational Fly Swarms, Troy Taylor May 2019

Quantifying Complex Systems Via Computational Fly Swarms, Troy Taylor

Senior Theses

Complexity is prevalent both in natural and in human-made systems, yet is not well understood quantitatively. Qualitatively, complexity describes a phenomena in which a system composed of individual pieces, each having simple interactions with one another, results in interesting bulk properties that would otherwise not exist. One example of a complex biological system is the bird flock, in particular, a starling murmuration. Starlings are known to move in the direction of their neighbors and avoid collisions with fellow starlings, but as a result of these simple movement choices, the flock as a whole tends to exhibit fluid-like movements and form ...


Predicting Chaotic Behavior In Electrical Circuits, Trey Scofield Apr 2019

Predicting Chaotic Behavior In Electrical Circuits, Trey Scofield

Carroll College Student Undergraduate Research Festival

Chaotic behavior is a natural phenomenon that can be found all around us in our daily lives. This project is focused on analyzing the behavior in forced RL-Diode (resistor, inductor, and diode) electrical circuits. We determined that when the sinusoidal input voltage of the circuit was increased, the voltage across the diode experienced period doubling, quadrupling, and then eventually chaos. Furthermore, this project is focused on predicting when and how these chaotic properties emerged from data that we collected. The primary machine learning technique that is used to predict chaos properties is a recurring neural network called an echo state ...


Dispersive Hydrodynamics In Viscous Fluid Conduits, Michelle Maiden Apr 2019

Dispersive Hydrodynamics In Viscous Fluid Conduits, Michelle Maiden

Applied Mathematics Graduate Theses & Dissertations

Viscous fluid conduits provide an ideal system for the study of dissipationless, dispersive hydrodynamics. A dense, viscous fluid serves as the background medium through which a lighter, less viscous fluid buoyantly rises. If the interior fluid is continuously injected, a deformable pipe forms. The long wave interfacial dynamics are well-described by a dispersive nonlinear partial differential equation called the conduit equation.

Experiments, numerics, and asymptotics of the viscous fluid conduit system will be presented. Structures at multiple length scales are characterized, including solitary waves, periodic waves, and dispersive shock waves. A more generic class of large-scale disturbances is also studied ...


Analytical Wave Solutions Of The Space Time Fractional Modified Regularized Long Wave Equation Involving The Conformable Fractional Derivative, M. Hafiz Uddin, Md. Ashrafuzzaman Khan, M. Ali Akbar, Md. Abdul Haque Mar 2019

Analytical Wave Solutions Of The Space Time Fractional Modified Regularized Long Wave Equation Involving The Conformable Fractional Derivative, M. Hafiz Uddin, Md. Ashrafuzzaman Khan, M. Ali Akbar, Md. Abdul Haque

Karbala International Journal of Modern Science

The space time fractional modified regularized long wave equation is a model equation to the gravitational water waves in the long-wave occupancy, shallow waters waves in coastal seas, the hydro-magnetic waves in cold plasma, the phonetic waves in dissident quartz and phonetic gravitational waves in contractible liquids. In nonlinear science and engineering, the mentioned equation is applied to analyze the one way tract of long waves in seas and harbors. In this study, the closed form traveling wave solutions to the above equation are evaluated due to conformable fractional derivatives through double (G'⁄G,1⁄G)-expansion method and the ...


A Detection And Data Acquisition System For Precision Beta Decay Spectroscopy, Aaron P. Jezghani Jan 2019

A Detection And Data Acquisition System For Precision Beta Decay Spectroscopy, Aaron P. Jezghani

Theses and Dissertations--Physics and Astronomy

Free neutron and nuclear beta decay spectroscopy serves as a robust laboratory for investigations of the Standard Model of Particle Physics. Observables such as decay product angular correlations and energy spectra overconstrain the Standard Model and serve as a sensitive probe for Beyond the Standard Model physics. Improved measurement of these quantities is necessary to complement the TeV scale physics being conducted at the Large Hadron Collider. The UCNB, 45Ca, and Nab experiments aim to improve upon existing measurements of free neutron decay angular correlations and set new limits in the search for exotic couplings in beta decay. To ...


Non-Convex Optimization And Applications To Bilinear Programming And Super-Resolution Imaging, Jessica Gronski Jan 2019

Non-Convex Optimization And Applications To Bilinear Programming And Super-Resolution Imaging, Jessica Gronski

Applied Mathematics Graduate Theses & Dissertations

Bilinear programs and Phase Retrieval are two instances of nonconvex problems that arise in engineering and physical applications, and both occur with their fundamental difficulties. In this thesis, we consider various methods and algorithms for tackling these challenging problems and discuss their effectiveness.

Bilinear programs (BLPs) are ubiquitous in engineering applications, economics, and operations research, and have a natural encoding to quadratic programs. They appear in the study of Lyapunov functions used to deduce the stability of solutions to differential equations describing dynamical systems. For multivariate dynamical systems, the problem formulation for computing an appropriate Lyapunov function is a BLP ...


Equilibrium Structures And Thermal Fluctuations In Interacting Monolayers, Emmanuel Rivera Jan 2019

Equilibrium Structures And Thermal Fluctuations In Interacting Monolayers, Emmanuel Rivera

Williams Honors College, Honors Research Projects

Coherency strains appear in interacting atomic monolayers due to differing bond lengths, which can arise from different materials or geometries. Examples include extended monolayers interacting with a substrate and the interacting walls of a multi-walled carbon nanotube. These strains can induce various equilibrium configurations, which we will analyze by means of a phenomenological model that incorporates forces from bond stretching and bending within each layer and the weak van der Waals interactions connecting the separate layers. We vary the strengths of each interaction to explore their effects on equilibrium structures, and the specific case of a two-walled carbon nanotube is ...


Systematic Exploration Of The Inverse Cascade In Rapidly Rotating Convection, Mitchell Krouss Jan 2019

Systematic Exploration Of The Inverse Cascade In Rapidly Rotating Convection, Mitchell Krouss

Undergraduate Honors Theses

A detailed investigation of the formation of large-scale vortices (LSVs) in rapidly rotating convection is carried out with an asymptotically-reduced model. The LSVs are generated by an inverse cascade of kinetic energy, which transfers kinetic energy from small length scales to large length scales. We can identify parameters, describing fluids, containing the presence of an inverse cascade by evaluating the transfer of kinetic energy to different wave numbers. We find a critical vertical Reynolds number that delineates the transition to flows which show a robust inverse cascade. The vertical Reynolds number can be fit with a multi-parameter power law, which ...


Numerical Simulations Of Convection With A Horizontal Magnetic Field, Talal Al-Refae Jan 2019

Numerical Simulations Of Convection With A Horizontal Magnetic Field, Talal Al-Refae

Undergraduate Honors Theses

A numerical study of magnetoconvection with a horizontal magnetic field in a plane layer geometry is conducted. Novel dynamical regimes are observed beyond those occurring in classical (i.e non-magnetic) Rayleigh-Bénard convection. Imposed magnetic field strengths up to Chandrasekhar numbers of Q = 106 are investigated. The most unstable flow configuration is two-dimensional rolls oriented parallel to the direction of the imposed magnetic field in which the induced magnetic field is identically zero. The convective roll structure exhibits a preferential flow alignment along the direction of the imposed magnetic field thereby sustaining an anisotropic flow field. Deviations away from the ...


Surface Waves Over Currents And Uneven Bottom, Alan C. Compelli, Rossen Ivanov, Calin I. Martin, Michail D. Todorov Jan 2019

Surface Waves Over Currents And Uneven Bottom, Alan C. Compelli, Rossen Ivanov, Calin I. Martin, Michail D. Todorov

Articles

The propagation of surface water waves interacting with a current and an uneven bottom is studied. Such a situation is typical for ocean waves where the winds generate currents in the top layer of the ocean. The role of the bottom topography is taken into account since it also influences the local wave and current patterns. Specific scaling of the variables is selected which leads to approximations of Boussinesq and KdV types. The arising KdV equation with variable coefficients, dependent on the bottom topography, is studied numerically when the initial condition is in the form of the one soliton solution ...


02 Getting Started With Vpython, W.A. Morgan, L.Q. English Jan 2019

02 Getting Started With Vpython, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

Chapter 2 serves as an introduction to the GlowScript VPython environment. The student is shown how to enter GlowScript via a browser. The student is asked to create simple programs, including ones that print, make shapes, and shown how to create comments in a program.


01 Introduction, W.A. Morgan, L.Q. English Jan 2019

01 Introduction, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

Readers are introduced to the structure of the book, including a discussion of the topics in each chapter, as well as how the book may be integrated in an introductory physics course.


03 Moving Objects Using Formulas, W.A. Morgan, L.Q. English Jan 2019

03 Moving Objects Using Formulas, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 3, the student is asked to program the motion of a ball with constant velocity, to plot the position with respect to time of the ball moving with constant velocity, and to simulate the motion of a ball undergoing a constant acceleration (near the surface of the Earth). The student is shown what is happening in a conditional loop. Finally, the student plots the circular motion of a body around an object, using trigonometric functions.


04 A First Look At Simulating Motion, W.A. Morgan, L.Q. English Jan 2019

04 A First Look At Simulating Motion, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 4, students are introduced to the mathematics behind the Euler method, as well as the coding involved. Students are given code and then asked to modify it.


08 Rotational Motion, Torque, And Angular Momentum, W.A. Morgan, L.Q. English Jan 2019

08 Rotational Motion, Torque, And Angular Momentum, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 8, students consider again the motion of a comet around the Sun, but now consider torque and angular momentum. Newton’s Law of Universal Gravitation is introduced, as well as the cross product and how to code it in VPython. Exercises are suggested.


10 Conclusion, W.A. Morgan, L.Q. English Jan 2019

10 Conclusion, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

This document provides a conclusion to VPython for Introductory Mechanics by Windsor A. Morgan and Lars Q. English. It includes the book’s bibliography as well as information about the authors.


09 Two Capstone Projects, W.A. Morgan, L.Q. English Jan 2019

09 Two Capstone Projects, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 9, students are introduced to the concept of Gravitational Assist, which is used to send probes to the outer planets and out of the solar system. Frames of reference are considered, as well as the energy of the probe and of the planet providing the assist. The code is provided, and exercises are suggested. Finally, chaotic orbital dynamics of an asteroid in the vicinity of a binary system is explored."


05 Visualizing Projectile Motion, W.A. Morgan, L.Q. English Jan 2019

05 Visualizing Projectile Motion, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 5, students are introduced to the kinematic equations describing an object undergoing a constant acceleration. Students are asked to write code simulating the flight of a projectile over level ground and sloping ground. The students are asked to have the projectile strike a target, using position vectors. The students are asked to annotate a VPython “mystery code”.


07 Conservation Of Momentum And Energy, W.A. Morgan, L.Q. English Jan 2019

07 Conservation Of Momentum And Energy, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 7, students are introduced to the concepts of center of mass, the impulse-momentum theorem, and conservation of energy. This is done by considering a binary star system, mass-spring system, and scattering in the Rutherford Experiment. Exercises are suggested.


06 Simulating Central-Force Problems, W.A. Morgan, L.Q. English Jan 2019

06 Simulating Central-Force Problems, W.A. Morgan, L.Q. English

VPython for Introductory Mechanics

In chapter 6, students are introduced to the idea of a central force, the idea of a instantaneous acceleration (as opposed to average acceleration) and using the Euler method to determine the position and velocity of the object. They then investigate the physics of a mass on a spring, a projectile in flight undergoing drag, and the motions of planets and comets around the Sun. They are asked to to do several exercises, including imagining a gravitational force that is goes as 1/r instead of 1/r2.


Vpython For Introductory Mechanics: Complete Version, Windsor A. Morgan, Lars Q. English Jan 2019

Vpython For Introductory Mechanics: Complete Version, Windsor A. Morgan, Lars Q. English

VPython for Introductory Mechanics

This book adds a computational dimension to introductory physics mechanics course, and is intended to accompany the textbook and other course materials for that course. It uses the programming language VPython in the browser-based GlowScript environment. It starts with simple computing and physics examples and moves to more sophisticated topics in succeeding chapters.

Computational topics include Position vs. Time Graphs, use of vectors, plotting motion of objects, and programming skills such as the cross product.

Physics topics include the kinematic equations, torque, angular momentum, projectile motion of a body, the law of universal gravitation, and gravitational assist.