Control Of Harmonic Generation By The Time Delay Between Two-Color, Bicircular Few-Cycle Mid-Ir Laser Pulses, 2018 Voronezh State University, Russia

#### Control Of Harmonic Generation By The Time Delay Between Two-Color, Bicircular Few-Cycle Mid-Ir Laser Pulses, M. V. Frolov, N. L. Manakov, A. A. Minina, N. V. Vvedenskii, A. A. Silaev, M. Yu. Ivanov, Anthony F. Starace

*Anthony F. Starace Publications*

We study control of high-order harmonic generation (HHG) driven by time-delayed, few-cycle ω and 2ω counterrotating mid-IR pulses. Our numerical and analytical study shows that the time delay between the two-color pulses allows control of the harmonic positions, both those allowed by angular momentum conservation and those seemingly forbidden by it. Moreover, the helicity of any particular harmonic is tunable from left to right circular without changing the driving pulse helicity. The highest HHG yield occurs for a time delay comparable to the fundamental period T = 2π/ω.

What Is A Photon? Foundations Of Quantum Field Theory, 2018 Utah State University

#### What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre

*All Physics Faculty Publications*

This is a brief, informal, and relatively low-level course on the foundations of quantum field theory. The prerequisites are undergraduate courses in quantum mechanics and electromagnetism.

Cuoricino Thermal Pulse Classification By Machine Learning Algorithms, 2018 California Polytechnic State University, San Luis Obispo

#### Cuoricino Thermal Pulse Classification By Machine Learning Algorithms, Joshua Mann

*Physics*

Many of the various properties of neutrinos are still a mystery. One unknown is whether neutrinos are Majorana fermions or Dirac fermions. Cuoricino and CUORE are experiments that aim to solve this mystery. Noise reduction in these experiments hinges on the ability to discern among alpha, beta and gamma particle detections using the thermal pulses they create. In this paper, we look at Cuoricino data and attempt to classify pulses, not as alpha, beta or gamma particles, but rather as signal, noise or calibration data. We will use this preliminary testing ground to examine various machine learning algorithms' abilities in ...

Electron- And Positron-Impact Ionization Of Inert Gases, 2018 Old Dominion University

#### Electron- And Positron-Impact Ionization Of Inert Gases, R. I. Campeanu, H. R. J. Walters, Colm T. Whelan

*Physics Faculty Publications*

Triple-differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions which cannot be separately detected in an experiment with a single projectile. A comparison is presented between theory and the recent experiments of [Gavin, deLucio, and DuBois, Phys. Rev. A95, 062703 (2017)] for *e ^{±}* and contrasted with the results from ...

What Is A Photon? Introduction To Quantum Field Theory, 2018 Department of Physics, Utah State University

#### What Is A Photon? Introduction To Quantum Field Theory, Charles G. Torre

*Charles G. Torre*

The Impact Of Ppb W/Z Lhc Data On Ncteq15 Parton Distribution Functions With An Emphasis On Refitting The Ncteq15 Npdf Set, 2018 Southern Methodist University

#### The Impact Of Ppb W/Z Lhc Data On Ncteq15 Parton Distribution Functions With An Emphasis On Refitting The Ncteq15 Npdf Set, Eric Godat

*Physics Theses and Dissertations*

As the LHC experiments increase their statistics and reduce their systematics, it is in- creasingly important to reduce the theoretical uncertainties so we can perform precision com- parisons. The parton distribution functions (PDFs) which describe the hadronic structure of protons and nuclei are the critical link between the experimental data and the proposed theoretical models; hence, a better understanding of the PDFs is essential for improved pre- dictions. Nuclear PDFs, in particular, have proven valuable in this regard, especially for flavor differentiation. I introduce ”nCTEQ+LHC,” the first PDF set fit using the nCTEQ formalism to include data from the ...

Lattice Scales From Gradient Flow And Chiral Analysis On The Milc Collaboration's Hisq Ensembles, 2018 Washington University in St. Louis

#### Lattice Scales From Gradient Flow And Chiral Analysis On The Milc Collaboration's Hisq Ensembles, Nathan Joseph Brown

*Arts & Sciences Electronic Theses and Dissertations*

The interactions of quarks and gluons form most of the visible matter around us. Yet, extracting precise predictions from the field theory describing them, Quantum Chromodynamics (QCD), is notoriously difficult. By simulating the QCD interaction on a Euclidean space time lattice, the field theory can be regularized non-perturbatively and familiar statistical techniques from classical statistical mechanics can be applied. Then, by systematically improving each component of the process, high precision results can be obtained. Some of the possible components to be improved include the discretization of the continuum action, the determination of the lattice scale(s), the generation of gauge ...

Quantum Fields In Extreme Backgrounds, 2018 Washington University in St. Louis

#### Quantum Fields In Extreme Backgrounds, Leandro Medina De Oliveira

*Arts & Sciences Electronic Theses and Dissertations*

Quantum field theories behave in interesting and nontrivial ways in the presence of intense electric and/or magnetic fields. Describing such behavior correctly, particularly at finite (nonzero) temperature and density, is of importance for particle physics, nuclear physics, astrophysics, condensed matter physics, and cosmology. Incorporating these conditions as external parameters also provides useful probes into the nonperturbative structure of gauge theories.

In this work, formalism for describing matter in a variety of extreme conditions is developed and implemented. We develop several expansions of one-loop finite temperature effects for spinor particles in the presence of magnetic fields, including the effects of ...

Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, 2018 University of Nebraska - Lincoln

#### Enhancing High-Order Harmonic Generation By Sculpting Waveforms With Chirp, Dian Peng, M. V. Frolov, Liang-Wen Pi, Anthony F. Starace

*Anthony F. Starace Publications*

We present a theoretical analysis showing how chirp can be used to sculpt two-color driving laser field waveforms in order to enhance high-order harmonic generation (HHG) and/or extend HHG cutoff energies. Specifically, we consider driving laser field waveforms composed of two ultrashort pulses having different carrier frequencies in each of which a linear chirp is introduced. Two pairs of carrier frequencies of the component pulses are considered: (ω, 2ω) and (ω, 3ω). Our results show how changing the signs of the chirps in each of the two component pulses leads to drastic changes in the HHG spectra. Our theoretical ...

Power Corrections To Tmd Factorization For Z-Boson Production, 2018 Old Dominion University

#### Power Corrections To Tmd Factorization For Z-Boson Production, I. Balitsky, A. Tatasov

*Physics Faculty Publications*

A typical factorization formula for production of a particle with a small transverse momentum in hadron-hadron collisions is given by a convolution of two TMD parton densities with cross section of production of the final particle by the two partons. For practical applications at a given transverse momentum, though, one should estimate at what momenta the power corrections to the TMD factorization formula become essential. In this paper we calculate the first power corrections to TMD factorization formula for Z-boson production and Drell-Yan process in high-energy hadron-hadron collisions. At the leading order in *N*_{c} power corrections are expressed in ...

Physics 516: Electromagnetic Phenomena (Spring 2018), 2018 University of Pennsylvania

#### Physics 516: Electromagnetic Phenomena (Spring 2018), Philip C. Nelson

*Department of Physics Papers*

These course notes are made publicly available in the hope that they will be useful. All reports of errata will be gratefully received. I will also be glad to hear from anyone who reads them, whether or not you find errors: pcn@upenn.edu.

Primordial Black Hole Atoms, 2018 Rowan University

#### Primordial Black Hole Atoms, David Zwick, Tyler Hanover, Brian Nepper

*Student Research Symposium Posters*

Primordial black holes are thought to have been formed at the early stages of the universe in the presence of non-homogeneous density distributions of dark matter. We are working under the assumption that dark matter consists of elementary low mass particles, specifically, spin 1/2 fermions. We further assume that dark matter is electrically neutral, thus its main interaction is gravitational. We investigate dark matter spin 1/2 fermions in orbit around a black hole atom and consider mass ranges for which the quantum description is appropriate. Solutions to the Dirac equation are utilized to describe the radial mass distribution ...

Pion Charge Exchange Cross Section On Liquid Argon, 2018 College of William and Mary

#### Pion Charge Exchange Cross Section On Liquid Argon, Kevin Nelson

*Undergraduate Honors Theses*

The discovery of neutrino oscillations allows for new studies on charge-parity (CP) violation in the neutrino sector. Such studies require detectors with high calorimetric and spatial resolution. The Liquid Argon Time Projection Chamber (LArTPC) is a new detector technology with higher energy and spatial resolution than previous neutrino detectors. The Liquid Argon In A Testbeam (LArIAT) experiment is a research and development LArTPC for the next generation of detectors. In this paper I present a methodology for measuring the pion Charge-Exchange (CEX) cross section with the LArIAT detector. This methodology uses the theory of the passage of particles through matter ...

Timelike Compton Scattering In The Gluex Experiment At Jefferson Lab, 2018 College of William and Mary

#### Timelike Compton Scattering In The Gluex Experiment At Jefferson Lab, Alexandra Cramer

*Undergraduate Honors Theses*

The structure of protons is a point of interest in nuclear physics due to the lack of consensus between the cumulative spin of a proton and the sum of the spins of its constituent quarks. In the GlueX Experiment at the Jefferson Lab Continuous Electron Beam Accelerator Facility (CEBAF), a particle physics process known as Timelike Compton Scattering (TCS), given by the reaction 𝛾𝑝 → 𝑝𝑒+𝑒-, can be used to help potentially explain this discrepancy. With an eventual goal of providing a comparison of the experimental GlueX TCS data to Generalized Parton Distribution (GPD) models, initial research focused on isolating ...

Cosmic Ray Muons In The Standard Model Of Fundamental Particles, 2018 George Mason University

#### Cosmic Ray Muons In The Standard Model Of Fundamental Particles, Angel Gutarra-Leon, Jorge Del Carpio Arispe, Cioli Barazandeh, Walerian Majewski

*Exigence*

Muons are one of the twelve fundamental particle types of matter, having relatively long free-particle lifetime. A muon decays into three other light particles (leptons) through action of the “weak” force, transmitted by the so-called “heavy photons” - bosons W^{+}/W^{-}. Muons are present in the secondary cosmic ray showers in the atmosphere and reach the sea level. By detecting the delay time between arrival of the muon and an appearance of the decay electron in our single scintillation detector, we measured the muon’s average lifetime at rest in the material of our detector. This compares well with the established ...

Time-Resolved Electron (E,2E) Momentum Spectroscopy: Application To Laser-Driven Electron Population Transfer In Atoms, 2018 University of Nebraska - Lincoln

#### Time-Resolved Electron (E,2E) Momentum Spectroscopy: Application To Laser-Driven Electron Population Transfer In Atoms, Hua-Chieh Shao, Anthony F. Starace

*Anthony F. Starace Publications*

Owing to its ability to provide unique information on electron dynamics, time-resolved electron momentum spectroscopy (EMS) is used to study theoretically a laser-driven electronic motion in atoms. Specifically, a chirped laser pulse is used to adiabatically transfer the populations of lithium atoms from the ground state to the first excited state. During this process, impact ionization near the Bethe ridge by time-delayed ultrashort, high-energy electron pulses is used to image the instantaneous momentum density of this electronic population transfer. Simulations with 100 fs and 1 fs pulse durations demonstrate the capability of EMS to image the time-varying momentum density, including ...

Light-Nuclei Spectra From Chiral Dynamics, 2018 Old Dominion University

#### Light-Nuclei Spectra From Chiral Dynamics, M. Piarulli, A. Baroni, L. Girlanda, A. Kievsky, A. Lovato, Ewing Lusk, L. E. Marcucci, Steven C. Pieper, R. Schiavilla, M, Viviani, R. B. Wiringa

*Physics Faculty Publications*

In recent years local chiral interactions have been derived and implemented in quantum Monte Carlo methods in order to test to what extent the chiral effective field theory framework impacts our knowledge of few- and many-body systems. In this Letter, we present Green's function Monte Carlo calculations of light nuclei based on the family of local two-body interactions presented by our group in a previous paper in conjunction with chiral three-body interactions fitted to bound- and scattering-state observables in the three-nucleon sector. These interactions include Δ intermediate states in their two-pion-exchange components. We obtain predictions for the energy levels ...

Warp Drive Spacetimes, 2018 Virginia Commonwealth University

#### Warp Drive Spacetimes, Nicholas A.S. Driver

*Theses and Dissertations*

The concept of faster than light travel in general relativity is examined, starting with a review of the Alcubierre metric. This spacetime, although incredible in its implications, has certain unavoidable problems which are discussed in detail. It is demonstrated that in order to describe faster than light travel without any ambiguities, a coordinate independent description is much more convenient. An alternative method of describing superluminal travel is then proposed, which has similarities to the Krasnikov tube.

Geodesic Structure In Schwarzschild Geometry With Extensions In Higher Dimensional Spacetimes, 2018 Virginia Commonwealth University

#### Geodesic Structure In Schwarzschild Geometry With Extensions In Higher Dimensional Spacetimes, Ian M. Newsome

*Theses and Dissertations*

From Birkoff's theorem, the geometry in four spacetime dimensions outside a spherically symmetric and static, gravitating source must be given by the Schwarzschild metric. This metric therefore satisfies the Einstein vacuum equations. If the mass which gives rise to the Schwarzschild spacetime geometry is concentrated within a radius of *r=2M*, a black hole will form. Non-accelerating particles (freely falling) traveling through this geometry will do so along parametrized curves called geodesics, which are curved space generalizations of straight paths. These geodesics can be found by solving the geodesic equation. In this thesis, the geodesic structure in the Schwarzschild ...

High Field Q Slope And The Effect Of Low-Temperature Baking At 3 Ghz, 2018 Old Dominion University

#### High Field Q Slope And The Effect Of Low-Temperature Baking At 3 Ghz, G. Ciovati, G. Eremeev, F. Hannon

*Physics Faculty Publications*

A strong degradation of the unloaded quality factor with field, called high field Q slope, is commonly observed above B_{p } ≅ 100 mT in elliptical superconducting niobium cavities at 1.3 and 1.5 GHz. In the present experiments several 3 GHz niobium cavities were measured up to and above B* _{p }* ≅ 100 mT. The measurements show that a high field Q slope phenomenon limits the field reach at this frequency, that the high field Q slope onset field depends weakly on the frequency, and that the high field Q slope can be removed by the typical empirical solution of ...