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Realization Of Bsu First Magneto-Optical Trap For The Spatial Confinement Of Rb Atoms Using Next Generation Fiber Optic Capabilities With Minimot, Brahmin Thurber-Carbone 2021 Bridgewater State University

Realization Of Bsu First Magneto-Optical Trap For The Spatial Confinement Of Rb Atoms Using Next Generation Fiber Optic Capabilities With Minimot, Brahmin Thurber-Carbone

Honors Program Theses and Projects

This paper will be a combination of my theoretical and experimental work toward Bridgewater State Universities first Magneto-Optical Trap (MOT) for laser cooling and trapping of neutral atoms in order to study fundamental quantum mechanical behavior of Rubidium (Rb) atoms. The goal of the theoretical aspect is to complete details of well-established works on how the complicated quantum, atomic, and electromagnetic (laser) interactions required to understand the design and operation of the MOT reduce to the physics and mathematics of a damped oscillator. This is made explicitly clear using familiar damped oscillator systems, such as a spring/mass/damping or pendulum/mass/damping (ie …


Magnetism And Topological Hall Effect In Antiferromagnetic Ru2Mnsn-Based Heusler Compounds, Wenyong Zhang, Balamurugan Balasubramanian, Yang Sun, Ahsan Ullah, Ralph Skomski, Rabindra Pahari, Shah R. Valloppilly, Xingzhong Li, Cai-Zhuang Wang, Kai-Ming Ho, David J. Sellmyer 2021 University of Nebraska - Lincoln

Magnetism And Topological Hall Effect In Antiferromagnetic Ru2Mnsn-Based Heusler Compounds, Wenyong Zhang, Balamurugan Balasubramanian, Yang Sun, Ahsan Ullah, Ralph Skomski, Rabindra Pahari, Shah R. Valloppilly, Xingzhong Li, Cai-Zhuang Wang, Kai-Ming Ho, David J. Sellmyer

Faculty Publications from Nebraska Center for Materials and Nanoscience

Heusler compounds and alloys based on them are of great recent interest because they exhibit a wide variety of spin structures, magnetic properties, and electron-transport phenomena. Their properties are tunable by alloying and we have investigated L21-ordered compound Ru2MnSn and its alloys by varying the atomic Mn:Sn composition. While antiferromagnetic ordering with a Néel temperature of 361 K was observed in Ru2MnSn, the Mn-poor Ru2Mn0.8Sn1.2 alloy exhibits properties of a diluted antiferromagnet in which there are localized regions of uncompensated Mn spins. Furthermore, a noncoplanar spin structure, evident from …


Laser-Excitation Spectroscopy Of Niobium Hydride And Tantalum Hydride, Siddhant Singh 2021 Macalester College

Laser-Excitation Spectroscopy Of Niobium Hydride And Tantalum Hydride, Siddhant Singh

Macalester Journal of Physics and Astronomy

The experimental results presented in this paper shed light on some of the fundamental bonding characteristics of NbH and TaH. Six bands of niobium hydride and five weak bands of tantalum hydride were observed for the first time using laser excitation spectroscopy. The rotational assignments of observed bands were confirmed using dispersed fluorescence experiments for NbH and by checking the internal consistency of a global least squares fit for the weaker bands of TaH. For TaH, we were able to determine the term energies and molecular constants of each of its observed states to a high degree of accuracy …


Simulating Many Body Localization With Rydberg Atoms, Alicia Handian 2021 Ursinus College

Simulating Many Body Localization With Rydberg Atoms, Alicia Handian

Physics and Astronomy Honors Papers

In thermodynamics, interacting systems are expected to achieve equilibrium with one another over the course of time. However, there are exceptions to this rule. When systems localize, or fail to reach equilibrium, information about the initial state of the system is preserved and locally observable after long periods of time. Many-body localization focuses on systems of interacting particles that fail to thermalize. We have developed a simulation that models the behavior of a many-body quantum system. The simulation is inspired by experiments conducted by Liu, et al., in their recent publication “Time Dependence of Few Body Forster Interactions Among Ultracold …


Structural Origin Of Thermal, Mechanical Properties And Morphological Behaviors Of Semiconducting Polymers, Song Zhang 2021 The University of Southern Mississippi

Structural Origin Of Thermal, Mechanical Properties And Morphological Behaviors Of Semiconducting Polymers, Song Zhang

Dissertations

The past decades have witnessed a surging exploration of semiconducting polymers for the application of wearable and flexible organic electronic devices. Despite the increased amounts of molecular engineered polymers and their much-improved electrical performances, a systematic study of the structure-thermal/mechanical property-morphology relationship of semiconducting polymers is still less investigated.

To understand the thin-film mechanical properties, a pseudo-free standing tensile tester was self-built and utilized to obtain their real-time stress-strain behaviors through uniaxial stretching on top of the water surface. It also enables the first quantitative measurement of fracture energy on ultrathin polymeric films. Through multiple mechanical testing methods (i.e., strain-rate …


Voltage-Controlled Magnetic Anisotropy In Antiferromagnetic Mgo-Capped Mnpt Films, P. H. Chang, Wuzhang Fang, T. Ozaki, Kirill Belashchenko 2021 University of Nebraska–Lincoln

Voltage-Controlled Magnetic Anisotropy In Antiferromagnetic Mgo-Capped Mnpt Films, P. H. Chang, Wuzhang Fang, T. Ozaki, Kirill Belashchenko

Kirill Belashchenko Publications

The magnetic anisotropy in MgO-capped MnPt films and its voltage control are studied using first-principles calculations. Sharp variation of the magnetic anisotropy with film thickness, especially in the Pt-terminated film, suggests that it may be widely tuned by adjusting the film thickness. In thick films the linear voltage control coefficient is as large as 1.5 and -0.6 pJ/Vm for Pt-terminated and Mn-terminated interfaces, respectively. The combination of a widely tunable magnetic anisotropy energy and a large voltage-control coefficient suggest that MgO-capped MnPt films can serve as a versatile platform for magnetic memory and antiferromagnonic applications.


Non-Gaussian Measurements Of Coherent States Of Light For Metrology And Communication, Matthew DiMario 2021 University of New Mexico

Non-Gaussian Measurements Of Coherent States Of Light For Metrology And Communication, Matthew Dimario

Physics & Astronomy ETDs

Conventional measurement technology is unable to extract the most amount of information possible from coherent states of light. Non-Gaussian measurements which can count individual photons can surpass the sensitivity limits of ideal conventional strategies, and approach the ultimate limits achievable given by quantum mechanics. This thesis presents investigations and demonstrations of these unconventional measurements, which utilize coherent operations and single photon counting. This thesis shows that non-Gaussian measurements can outperform conventional strategies in estimation tasks as well as a variety of communication problems. This thesis also investigates novel approaches and algorithms for building robustness to static and dynamic noise which …


Progress Towards Electromagnetic Manipulation And Trapping Of Micro-Particles, Andrew John Beling 2021 College of William & Mary

Progress Towards Electromagnetic Manipulation And Trapping Of Micro-Particles, Andrew John Beling

Undergraduate Honors Theses

This thesis describes research to investigate the electromagnetic manipulation of microspheres and microrings. The work consists of three main thrusts: 1) the use of an electric field gradient to move dielectric microspheres, 2) the use of an AC magnetic field to move a conducting ring, and 3) the preparation of substrates for a microwave atom chip. The electrostatic movement of dielectric polyethylene microspheres was observed and recorded with a CCD imaging system. The microspheres were suspended in various liquids and placed on top of a microstrip transmission line, which consists of a conducting copper trace separated from a ground plate …


Single-Shot Positron Annihilation Lifetime Spectroscopy Using A Liquid Scintillator, Joshua R. Machacek, Shawn McTaggart, Larry W. Burggraf 2021 Air Force Institute of Technology

Single-Shot Positron Annihilation Lifetime Spectroscopy Using A Liquid Scintillator, Joshua R. Machacek, Shawn Mctaggart, Larry W. Burggraf

Faculty Publications

Liquid scintillators provide a fast, single component response. However, they traditionally have a low flashpoint and high vapor pressure. We demonstrate the use of an EJ-309 scintillator (high flashpoint and low vapor pressure variant) to acquire single-shot positron annihilation lifetime spectroscopy spectra using a trap-based positron beam.


Quantum Dynamical Phenomena In Non-Hermitian And Magnomechanical Systems, Saeid Vashahri Ghamsari 2021 University of Arkansas, Fayetteville

Quantum Dynamical Phenomena In Non-Hermitian And Magnomechanical Systems, Saeid Vashahri Ghamsari

Graduate Theses and Dissertations

In this dissertation, we have investigated quantum dynamics via three case studies. First, we studied a system of two coupled waveguides respectively carrying optical damping and optical gain in addition to squeezing elements in one or both waveguides. Such a system is expected to generate highly entangled light fields in the two waveguides. We, however, show that the degree of the created entanglement is significantly affected by the quantum noises associated with the amplification and dissipation. Because of the noise effect, one can only have nonzero entanglement for a limited time interval. Second, we generalized the first project by considering …


Simulation Of Optical Properties Of Dielectric Layers From Visible To Near Infrared Spectral Range, Andrew Cochran, Cory Conkel 2021 Ohio Northern University

Simulation Of Optical Properties Of Dielectric Layers From Visible To Near Infrared Spectral Range, Andrew Cochran, Cory Conkel

ONU Student Research Colloquium

Optical properties of dielectrics play a critical role in various applications including the design and manufacture of optical components & devices such as detectors, filters, imagers, lenses, optical coatings, photonic crystals, sensors and waveguides, and solar cells. Radiative properties of varying thicknesses of different dielectrics such as Aluminum Oxide (Al2O3), Silicon Dioxide (SiO2), Indium Tin Oxide (ITO), Magnesium Fluoride (MgF2) and Silicon Nitride (Si3N4) have been simulated and compared in the range of visible to near infrared by mathematical modelling using MATLAB simulations. The results of the evolution of the radiative properties, as a function of dielectric material thickness, on …


Enhanced Nonlinear Interaction Of Polaritons Via Excitonic Rydberg States In Monolayer Wse2, Jie Gu, Valentin Walther, Lutz Waldecker, Daniel Rhodes, Archana Raja, James C. Hone, Tony F. Heinz, Stéphane Kéna-Cohen, Thomas Pohl, Vinod M. Menon 2021 CUNY City College

Enhanced Nonlinear Interaction Of Polaritons Via Excitonic Rydberg States In Monolayer Wse2, Jie Gu, Valentin Walther, Lutz Waldecker, Daniel Rhodes, Archana Raja, James C. Hone, Tony F. Heinz, Stéphane Kéna-Cohen, Thomas Pohl, Vinod M. Menon

Publications and Research

Strong optical nonlinearities play a central role in realizing quantum photonic technologies. Exciton-polaritons, which result from the hybridization of material excitations and cavity photons, are an attractive candidate to realize such nonlinearities. While the interaction between ground state excitons generates a notable optical nonlinearity, the strength of such interactions is generally not sufficient to reach the regime of quantum nonlinear optics. Excited states, however, feature enhanced interactions and therefore hold promise for accessing the quantum domain of single-photon nonlinearities. Here we demonstrate the formation of exciton-polaritons using excited excitonic states in monolayer tungsten diselenide (WSe2) embedded in a …


Direct Visualization Of 3-Dimensional Force And Energy Map Of A Single Molecular Switch, Abeykoon Mudiyanselage Shashika Darshani Wijerathna, Zaw Myo Win, K. Z. Latt, Yang Li, A. T. Ngo, L. Curtiss, R. Zhang, S. W. Hla, Y. Zhang 2021 Old Dominion University

Direct Visualization Of 3-Dimensional Force And Energy Map Of A Single Molecular Switch, Abeykoon Mudiyanselage Shashika Darshani Wijerathna, Zaw Myo Win, K. Z. Latt, Yang Li, A. T. Ngo, L. Curtiss, R. Zhang, S. W. Hla, Y. Zhang

College of Sciences Posters

Mechanical properties of molecules adsorbed on materials surfaces are increasingly vital for the applications of molecular thin films. Here, we conduct a fundamental research to induce conformational change mechanically on a single molecule and quantify the driving force needed for such molecular shape switch via a low temperature (~ 5K) Scanning Tunneling Microscope (STM) and Qplus Atomic Force Microscope (Q+AFM). Our measurement maps a three-dimensional landscape for mechanical potential and force at single molecule level with high spatial resolution in all three dimensions of a few angstrom (10-10 m).

Molecule TBrPP-Co (a cobalt porphyrin) deposited on an atomically clean …


Dipole Emission Characteristics Near A Topological Insulator Sphere Coated With A Metallic Nanoshell, Huai-Yi Xie, Railing Chang, P. T. Leung 2021 Institute of Nuclear Energy Research, Atomic Energy Council

Dipole Emission Characteristics Near A Topological Insulator Sphere Coated With A Metallic Nanoshell, Huai-Yi Xie, Railing Chang, P. T. Leung

Physics Faculty Publications and Presentations

Topological insulators (TI) are quantum states of (2D/3D) matter with an insulating interior but conducting edge/surface states, with these boundary conducting states being protected topologically by time-reversal symmetry. Composite materials of heavy atoms such as Bi2Te3 can be fabricated to show TI properties due to the strong intrinsic spin-orbit coupling of the electrons in these materials. Among the so many intriguing physical properties of these materials, their topological magneto-electric (TME) response is unique and has been studied intensively in the literature, leading to intriguing optical effects such as Faraday and Kerr rotations of incident polarized beams at …


Toward Improving Understanding Of The Structure And Biophysics Of Glycosaminoglycans, Elizabeth K. Whitmore 2021 University of New England

Toward Improving Understanding Of The Structure And Biophysics Of Glycosaminoglycans, Elizabeth K. Whitmore

Electronic Theses and Dissertations

Glycosaminoglycans (GAGs) are the linear carbohydrate components of proteoglycans (PGs) that mediate PG bioactivities, including signal transduction, tissue morphogenesis, and matrix assembly. To understand GAG function, it is important to understand GAG structure and biophysics at atomic resolution. This is a challenge for existing experimental and computational methods because GAGs are heterogeneous, conformationally complex, and polydisperse, containing up to 200 monosaccharides. Molecular dynamics (MD) simulations come close to overcoming this challenge but are only feasible for short GAG polymers. To address this problem, we developed an algorithm that applies conformations from unbiased all-atom explicit-solvent MD simulations of short GAG polymers …


Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner 2021 University of Nebraska - Lincoln

Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner

Honors Theses, University of Nebraska-Lincoln

This thesis describes the experimental apparatus and procedure used to measure the excitation function of the 2p53p 3D3 state of neon. First I describe the effect on this excitation of negative ion resonances and previous experiments to measure the excitation function, as well as suggestions for future applications of such studies. Then the experimental apparatus is described in three parts. The vacuum system uses a turbomolecular pump to decrease the pressure of the chamber to as low as 4*10-9 Torr. The electron beam system incorporates a trochoidal electron monochromator to send a highly monochromatic beam …


Implementing Inverse Design Tools For Plasmonic Digital Logic Devices, Krishna Narayan, Mark C. Harrison 2021 Chapman University

Implementing Inverse Design Tools For Plasmonic Digital Logic Devices, Krishna Narayan, Mark C. Harrison

Engineering Faculty Articles and Research

Despite the benefits that optics and photonics have brought to improving communications, there remains a lack of commercialized optical computing devices and systems, which reduces the benefits of using light as an information-carrying medium. We are developing architectures and designs of photonic logic gates for creating larger-scale functional photonic logic circuits. In contrast to other approaches, we are focusing on the development of logic devices which can be cascaded in arbitrary ways to allow for more complex photonic integrated circuit design. Additionally, optical computing often uses on-off keying, which fails to take advantage of denser encoding schemes often used to …


Correction To "Quantitative Study Of The Energy Changes In Voltage-Controlled Spin Crossover Molecular Thin Films" [The Journal Of Physical Chemistry Letters (2020) 11:19 (8231-8237) Doi: 10.1021/Acs.Jpclett.0c02209], Aaron Mosey, Ashley S. Dale, Guanhua Hao, Alpha N'Diaye, Peter Dowben, Ruihua Cheng 2021 Indiana University-Purdue University Indianapolis

Correction To "Quantitative Study Of The Energy Changes In Voltage-Controlled Spin Crossover Molecular Thin Films" [The Journal Of Physical Chemistry Letters (2020) 11:19 (8231-8237) Doi: 10.1021/Acs.Jpclett.0c02209], Aaron Mosey, Ashley S. Dale, Guanhua Hao, Alpha N'Diaye, Peter Dowben, Ruihua Cheng

Peter Dowben Publications

In our recent publication, Figure 5 was published without adequate due diligence. The correct TOC Abstract graphic and Figure 5 are contained here in this correction. The correct on to off current ratios are in the range of 4 to 5, not 100 and the signal to noise ratios are far less than previously shown.


Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer 2021 University of Nebraska - Lincoln

Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer

Honors Theses, University of Nebraska-Lincoln

When an electron beam travels through space, it spreads out over time which impedes the ability to work with short electron pulses in the lab. A Wien filter is a device consisting of perpendicular electric and magnetic fields which filters charged particles based on their velocities. For a specific velocity, the two forces from the two fields in the filter cancel each other out letting charges with that velocity travel straight through the filter. Charges moving at other speeds are deflected as they have a net force applied to them from the filter. If a particle is deflected from the …


Nonvolatile Voltage Controlled Molecular Spin‐State Switching For Memory Applications, Thilini K. Ekanayaka, Guanhua Hao, Aaron Mosey, Ashley S. Dale, Xuanyuan Jiang, Andrew J. Yost, Keshab R. Sapkota, George T. Wang, Jian Zhang, Alpha T. N’Diaye, Andrew Marshall, Ruihua Cheng, Azad Naeemi, Xiaoshan Xu, Peter Dowben 2021 University of Nebraska–Lincoln

Nonvolatile Voltage Controlled Molecular Spin‐State Switching For Memory Applications, Thilini K. Ekanayaka, Guanhua Hao, Aaron Mosey, Ashley S. Dale, Xuanyuan Jiang, Andrew J. Yost, Keshab R. Sapkota, George T. Wang, Jian Zhang, Alpha T. N’Diaye, Andrew Marshall, Ruihua Cheng, Azad Naeemi, Xiaoshan Xu, Peter Dowben

Peter Dowben Publications

Nonvolatile, molecular multiferroic devices have now been demonstrated, but it is worth giving some consideration to the issue of whether such devices could be a competitive alternative for solid-state nonvolatile memory. For the Fe (II) spin crossover complex [Fe{H2B(pz)2}2(bipy)], where pz = tris(pyrazol-1-yl)-borohydride and bipy = 2,20-bipyridine, voltage-controlled isothermal changes in the electronic structure and spin state have been demonstrated and are accompanied by changes in conductance. Higher conductance is seen with [Fe{H2B(pz)2}2(bipy)] in the high spin state, while lower conductance occurs for the low spin state. Plausibly, …


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