Knotty Inflation And The Dimensionality Of Spacetime, 2017 University of Edinburgh

#### Knotty Inflation And The Dimensionality Of Spacetime, Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich Päs, João G. Rosa

*Mathematics, Physics, and Computer Science Faculty Articles and Research*

We suggest a structure for the vacuum comprised of a network of tightly knotted/linked flux tubes formed in a QCD-like cosmological phase transition and show that such a network can drive cosmological inflation. As the network can be topologically stable only in three space dimensions, this scenario provides a dynamical explanation for the existence of exactly three large spatial dimensions in our Universe.

Sources Of Gravity.Docx, 2017 Yanbikov Vildyan Shavkyatovich

#### Sources Of Gravity.Docx, Vildyan Yanbikov

*Vildyan Yanbikov*

Empty Universe.Docx, 2017 Yanbikov Vildyan Shavkyatovich

#### Empty Universe.Docx, Vildyan Yanbikov

*Vildyan Yanbikov*

Quantum Physics And Relativity In Lovecraft's Fiction, 2017 Ursinus College

#### Quantum Physics And Relativity In Lovecraft's Fiction, Garrison Mccammon

*English Summer Fellows*

The early twentieth century brought about some of the best and most influential horror or weird tales ever written in the English speaking world. The most impressive and most lauded author of the group composed of such figures as Algernon Blackwood, M. R. James, Arthur Machen, Clark A. Smith, and Robert E. Howard was H. P. Lovecraft. Posthumously declared the literary successor to Edgar Allan Poe, Lovecraft’s fiction and tales of terror have cast such a huge shadow that every significant author in weird writing since his passing has claimed him as a literary heir. Lovecraft’s works were ...

Gravitational Wave Behavior At A Vacuum-Matter Interface, 2017 University of Puget Sound

#### Gravitational Wave Behavior At A Vacuum-Matter Interface, Jake Litterer

*Honors Program Theses*

In classical electrodynamics, boundary conditions of the E and B fields are derived from Maxwell's equations, which are used to derive the Fresnel equations describing the behavior of a wave at an interface between media with given indices of refraction. Though electrodynamics and gravity are in some instances strikingly analogous, boundary conditions in general relativity are somewhat more opaque. We will see that while while continuity of the metric must be true in general, discontinuity of the extrinsic curvature of spacetime, while allowed by the Einstein field equations, results in a singularity in the energy-momentum tensor. This singularity is ...

Literature Review: Biomimetic And Conventional Aircraft Wing Tips, 2017 International Islamic University - Malaysia

#### Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman

*International Journal of Aviation, Aeronautics, and Aerospace*

This paper is an attempt to summarize the effect of wing tip devices employed by birds, as well as aeronautical engineers in the past to improve the performance characteristics of aircraft. The focus is on reduction of the induced drag or drag due to lift also known as inviscid drag. This paper will provide an insight on both biomimetic and conventional wing tip approaches to reduce the induced drag. Prior analysis and experiments on the aerodynamics of airplane performance due to both these separate studies have been discussed. The needs of the industry and their past inventions have been described ...

An Analysis Of The Effects Of Isocurvature Fluctuations In Dantes Inferno Multi-Field Inflation Models, 2017 College of William and Mary

#### An Analysis Of The Effects Of Isocurvature Fluctuations In Dantes Inferno Multi-Field Inflation Models, Brandon M. Buncher

*Undergraduate Honors Theses*

Although there is significant evidence of inflation (a period of rapid expansion of the early universe), a definitive model of the epoch has not yet been widely accepted. A variety of models exist which describe this period; however, current technology cannot adequately measure several key factors that would demonstrate the veracity of these models. A major differentiator between classes of models is the number of fields that contribute to the inflationary epoch. Single-field inflation models assume the existence of a single field, though the details of this field vary depending on the model, while multi-field inflation models assume the existence ...

Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, 2017 Georgia College and State University

#### Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee

*Georgia College Student Research Events*

Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. We present a continuation of a 1-d likelihood analysis on gamma-ray observations by Fermi-LAT (0.1-10 GeV) of the accreting black hole candidate Cygnus X-1. Combining this gamma-ray data with available X-ray monitoring data from Swift and MAXI allowed us to reveal over a dozen days (in 2008-2016) during which Cyg X-1 displayed low-significance (3-4 sigma) excesses, many of which were contemporaneous with apparent transitions in the X-rays.

Vacuum.Doc, 2017 Yanbikov Vildyan Shavkyatovich

#### Vacuum.Doc, Vildyan Yanbikov

*Vildyan Yanbikov*

Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., 2017 Swiss National Supercomputing Centre

#### Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., C. Gheller, F. Vazza, M. Brüggen, M. Alpaslan, Benne W. Holwerda

*Benne Holwerda*

Despite containing about a half of the total matter in the Universe, at most wavelengths the filamentary structure of the cosmic web is difficult to observe. In this work, we use large unigrid cosmological simulations to investigate how the geometrical, thermodynamical and magnetic properties of cosmological filaments vary with mass and redshift (z ≤ 1). We find that the average temperature, length, volume and magnetic field of filaments scales well with their total mass. This reflects the role of self-gravity in shaping their properties and enables statistical predictions of their observational properties based on their mass. We also focus on the ...

Short-Period Mesospheric Gravity Waves And Their Sources At The South Pole, 2017 Merrimack College

#### Short-Period Mesospheric Gravity Waves And Their Sources At The South Pole, Dhvanit Mehta, Andrew J. Gerrard, Yusuke Ebihara, Allan T. Weatherwax, Louis J. Lanzerotti

*Physics Faculty Publications*

The sourcing locations and mechanisms for short-period, upward-propagating gravity waves at high polar latitudes remain largely unknown. Using all-sky imager data from the Amundsen–Scott South Pole Station, we determine the spatial and temporal characteristics of 94 observed small-scale waves in 3 austral winter months in 2003 and 2004. These data, together with background atmospheres from synoptic and/or climatological empirical models, are used to model gravity wave propagation from the polar mesosphere to each wave's source using a ray-tracing model. Our results provide a compelling case that a significant proportion of the observed waves are launched in several ...

Effects Of Low-Temperature Reheating On The Matter Power Spectrum, 2017 Colgate University

#### Effects Of Low-Temperature Reheating On The Matter Power Spectrum, Jonah Kudler-Flam

*Senior Honors Theses*

The thermal and expansion history of the universe between inflation and big bang nucleosynthesis is largely unconstrained. In standard cosmological theories, highly relativistic standard model particles dominate the universe’s energy density during this epoch. We consider a non-standard cosmology consisting of an era dominated by an oscillating scalar field that behaves similarly to matter. The growth of density perturbations is strongly enhanced in an early matter dominated era (EMDE), leading to potentially profound consequences regarding the dynamics of the early universe and the scales of the first bound dark matter structures. We investigate the applications and validity of the ...

Two Topics In Astrophysics: Exoplanetary Gravitational Microlensing And Radio Interferometry, 2017 Bard College

#### Two Topics In Astrophysics: Exoplanetary Gravitational Microlensing And Radio Interferometry, Eleanor Sara Turrell

*Senior Projects Spring 2017*

Senior Project submitted to The Division of Science, Mathematics and Computing of Bard College.

Gravity Wave And Turbulence Transport In The Mesopause Region, 2017 Embry-Riddle Aeronautical University

#### Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo

*Dissertations and Theses*

Vertical transport due to dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 ...

Environmentally Driven Galaxy Evolution And Quenching: Insights From The Low-Redshift Circumgalactic Medium, 2017 University of Massachusetts Amherst

#### Environmentally Driven Galaxy Evolution And Quenching: Insights From The Low-Redshift Circumgalactic Medium, Joseph Burchett

*Doctoral Dissertations*

The gaseous halos of galaxies -- the circumgalactic medium (CGM) -- serve as interfaces playing host to the fueling and feedback processes that sustain and regulate star formation. Furthermore, interactions between galaxies one with another and with larger scale structure, such as galaxy cluster halos, must necessarily act through the CGM. This dissertation examines the CGM as traced by H I, C IV, and O VI absorption lines across wide range of halo environments, from isolated dwarf galaxies with M_{*} < 10^{8 }M_{sun} to galaxy clusters with M_{halo} > 10^{14} M_{sun}. By first conducting a blind survey of C IV ...

Production Of Cosmological Observables During The Inflationary Epoch, 2017 University of Massachusetts Amherst

#### Production Of Cosmological Observables During The Inflationary Epoch, Cody Goolsby-Cole

*Doctoral Dissertations*

This dissertation proposal explores the production of present day cosmological observables which might have been produced during the inflationary era. The first observable is the current net electric charge of our observable universe produced by charge fluctuations during inflation. Next, we examine the possibility of a signal in the primordial gravitational wave power spectrum produced by a scalar field with a time dependent mass. Finally, we examine primordial magnetic fields produced during inflation through the Ratra model coupling with the Schwinger effect.

Statistical Modeling And Beam Analysis For The Redshifted Global 21 Centimeter Signal, 2017 University of Colorado, Boulder

#### Statistical Modeling And Beam Analysis For The Redshifted Global 21 Centimeter Signal, Katherine Pellicore

*Undergraduate Honors Theses*

This thesis explores two aspects of measurements of the global 21 cm signal through analytical simulations. We first attempt to understand how well the global 21 cm signal could be extracted from measurements of the sky. We accomplish this by employing a Fisher matrix analysis to estimate the uncertainties of cosmological parameters for simple measurement models that assume a perfectly calibrated instrument. We find that the assumed parameters of the signal can be constrained to high precision under realistic scenarios of noise and foreground contaminants. We also study the bias in the cosmological parameters due to modeling errors using a ...

Series Solutions Of Polarized Gowdy Universes, 2017 Virginia Commonwealth University

#### Series Solutions Of Polarized Gowdy Universes, Doniray Brusaferro

*Theses and Dissertations*

Einstein's field equations are a system of ten partial differential equations. For a special class of spacetimes known as Gowdy spacetimes, the number of equations is reduced due to additional structure of two dimensional isometry groups with mutually orthogonal Killing vectors. In this thesis, we focus on a particular model of Gowdy spacetimes known as the polarized T^{3} model, and provide an explicit solution to Einstein's equations.

Exotic Statistics For Strings In 4d Bf Theory, 2016 University of California, Riverside

#### Exotic Statistics For Strings In 4d Bf Theory, John C. Baez, Derek K. Wise, Alissa S. Crans

*Alissa Crans*

After a review of exotic statistics for point particles in 3d BF theory, and especially 3d quantum gravity, we show that string-like defects in 4d BF theory obey exotic statistics governed by the 'loop braid group'. This group has a set of generators that switch two strings just as one would normally switch point particles, but also a set of generators that switch two strings by passing one through the other. The first set generates a copy of the symmetric group, while the second generates a copy of the braid group. Thanks to recent work of Xiao-Song Lin, we can ...

Elasticity Of Cylindrical Black Holes, 2016 California Polytechnic State University, San Luis Obispo

#### Elasticity Of Cylindrical Black Holes, Conrad Pearson

*Physics*

Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior ...