Atomic, Molecular and Optical Physics Commons^™

Electronic Structure Discretization And Compression Using Diagonal Basis Sets, Casey Lee Dowdle

Dartmouth College Ph.D Dissertations

Numerically solving the electronic structure problem is a fundamentally difficult problem due to the exponential growth in the dimension of the Hilbert space as the system size increases. In order to solve problems at a chemically relevant accuracy, both the choice of basis set and numerical method are important factors that are intrinsically connected.

In this thesis, we study the discretization and resulting compression of electronic Hamiltonians using diagonal basis sets. A diagonal basis set approximately diagonalizes the matrix and tensor representations of the one- and two-body potentials. This can reduce storage, simplify matrix-vector products, and lower the complexity of …

Algorithmic Sculpting Of Complex Fused Silica Surfaces For Nondestructive, Mode-Matched Cavity Quantum Electrodynamics: Adaptive Co2 Milling And Simulation-Guided Ultrafast Inscription, From Fiber Fabry-Perot Cavities To Monolithic Architectures, Meagan E. Parker

Optical Science and Engineering ETDs

Quantum sensors achieve exceptional measurement sensitivity through coherent, well-isolated quantum systems, but practical deployment is hindered by destructive readouts that require repeated state preparation and create long system dead times. Optical cavities enable continuous, nondestructive measurements with minimal back-action, yet integrating high-finesse cavities into scalable quantum devices remains limited by existing fabrication methods. To overcome these constraints, an adaptive CO₂ laser-milling platform was developed. Guided by glass thermodynamics and melt dynamics, this closed-loop system uses in-situ phase-shifting interferometry to sculpt complex fused-silica surfaces with sub-nanometer root-mean-square roughness. The platform was validated by fabricating extended-length fiber Fabry–Pérot cavities and monolithic micro-cavity …

Coherent Two-Photon Backscattering And Induced Angular Quantum Correlations In Multiple-Scattered Two-Photon States Of The Light, Nooshin M. Estakhri, Theodore B. Norris

Engineering Faculty Articles and Research

We present the emergence of coherent two-photon backscattering, a manifestation of weak localization, in multiple scattering of maximally entangled pure and fully mixed two-photon states and examine the effect of entanglement and classical correlations. Quantum correlations in backscattering are investigated for finite three-dimensional disordered structures in the weak localization regime, as well as systems of a small number of scatterers with specified spatial arrangements. No assumptions are made about the statistical behavior of the scattering matrix elements. Furthermore, we study the interplay between quantum correlations induced by multiple scattering and the correlations that may be present in the illumination fields, …

Optical Nuclear Spin Detection In Diamond And Varifocal Metasurface Optics, Maxwell D. Aiello

Physics & Astronomy ETDs

This dissertation presents two experimental investigations at the intersection of quantum sensing and precision optical instrumentation. The primary project demonstrates optically detected nuclear magnetic resonance (NMR) of ¹³C nuclear spins in diamond, using state-selective Landau-Zener transitions under microwave frequency sweeping to bidirectionally transfer spin polarization between nitrogen-vacancy (NV) electron spins and remote ¹³C nuclear spins. This enables optical polarization and readout of large ensembles of polarized nuclear spins at low magnetic fields and room temperature, with spin dephasing times limited by longitudinal relaxation of nearby NV electron spins. The secondary project reports the design, fabrication, and characterization of …

Calculating Potential Energy Curves Of Molecular Hydrogen And Its Ion Using Psi4 For Blinc Fusion Applications*, Angelina Castillo, Oscar Coral, Canaan Hercules, Blake Laing, Vola Andrianarijaona

Campus Research Month

Southern Adventist University’s Beamline for Ionic and Neutral Collisions (BLINC) is investigating the interactions between hydrogen molecules and fusion particles. To perform in-house theoretical calculations, the BLINC Theory and Analysis Group is testing Psi4 as a viable computational method for BLINC fusion research. Successful calculations of the potential energy curves and dissociation energies of H₂ and H₂⁺ have been completed and compared to known values. Preliminary results align with known values, demonstrating Psi4’s potential for BLINC research. Future work will focus on the vibrational energies, wavefunctions, and transition probabilities of H₂ and H₂⁺.

Satellite-Mediated Quantum Clock Synchronization: Towards Precise Timing At A Global Scale, Sage B. Ducoing

LSU Doctoral Dissertations

Accurate timekeeping is essential for scientific and technological advancements, particularly in areas of communication, networking, navigation, and high precision measurements. While many methods of time resolution are already established using classical resources, they fail to combine high precision outcomes with large-scale implementations. Additionally, numerous quantum networking architectures using satellite-assisted methods have demonstrated quantum communication on scales exceeding ground-based methods. For these reasons, we propose the use of a time synchronization method by which pairs of highly time-correlated photons are exchanged between clocks on satellites and clocks on Earth, al- lowing users to reconstruct the time offsets between their clocks. This …

Simulating Chemiluminescence Spectra Of Oh Radical Using Quantum Dynamical Simulations, Triet M. Cao

Research from the Berry Summer Thesis Institute, 2025

Chemiluminescence is a phenomenon of light emission that occurs when molecules transition from an excited state to the ground state. This phenomenon is widely utilized in applications ranging from quantifying product yields in chemical reactions to biological imaging and atmospheric chemistry studies. It has also been used in many crucial applications in the scarce conditions of heat and electricity, such as light sources for astronomy discovery or deep-sea diving. A notable example of such reactions is combustion, where highly reactive hydroxyl radicals (OH) are products. These radicals exhibit a chemiluminescence spectrum because of the interaction between their ground state and …

Non-Linear Atom-Laser Interactions Using Rubidium Pump-Probe Spectroscopy, Grace Neil

Beyond: Undergraduate Research Journal

An experiment was performed to demonstrate the pump-probe spectroscopy of Rubidium (Rb) vapor, revealing the nonlinear atom-laser interactions in the 5S1/2 ↔ 5D5/2 transition in Rb that can be used to generate quantum entanglement between two laser beams. The setup included a tunable infrared diode laser, optical mirrors, photodiode-detectors, a beam-splitter, and a temperature- regulated rubidium gas chamber, all of which are controlled by the TeachSpin laser controller and monitor. The output from the laser-diode was split into a pump (90%) and a signal probe (10%), which intersected in counter-propagating directions inside the Rubidium chamber. The analysis shows that in …

Phase Nanoscopy With Correlated Frequency Combs, Xiaobing Zhu

Optical Science and Engineering ETDs

In this dissertation a sensing method applying to any physical quantity that modifies optical phase is developed. Two pulses are produced inside a synchronously pumped Optical Parametric Oscillator, generating two identical, undistinguishable frequency combs. The physical quantity to be measured applies a small phase shift/round trip to one of the pulses, resulting in a frequency shift of the corresponding comb. The latter frequency is measured as a beat by interfering the two combs on a detector. A world record resolution, close to the quantum limit, of 0.033 nanoradian (corresponding to 0.006 fm in displacement) is achieved. A detailed analysis of …

Advancing Diamond Quantum Sensors: Isotropic Flux Concentrators And Phase Noise Mitigation, Maziar Saleh Ziabari

Optical Science and Engineering ETDs

Two methods for improving the sensitivity of nitrogen vacancy quantum sensors in diamond are explored. First, by passively concentrating the magnetic flux, three orthogonally oriented ferrite truncated cone pairs amplify the field isotropically by 19 times, allowing measurement of Earth's field without a bias field and increasing sensitivity. Through thorough analysis, modeling and tuning a novel 3-dimensional flux concentrator system, we achieve a fractional standard deviation of less than 1% anisotropy and quantify minimal deadzones and ambient temperature-limited variations below 40 nT/hour. Second, we characterize, model and calculate phase noise in NV experiments, which in NV sensors is effectively indistinguishable …

Theoretical Proof Of And Proposed Experimental Search For The Ground Triplet State Of A Wigner-Regime Two-Electron ‘Artificial Atom’ In A Magnetic Field, Marlina Slamet, Viraht Sahni

Publications and Research

It is experimentally established that there is no ground triplet state of the natural He atom. There is also no exact analytical solution to the Schrödinger equation corresponding to this state. For a two-dimensional two-electron ‘artificial atom’ or a semiconductor quantum dot in a magnetic field, as described by the Schrödinger–Pauli equation, we provide theoretical proof of the existence of a ground triplet state by deriving an exact analytical correlated wave function solution to the equation. The state exists in the Wigner high-electron-correlation regime. We further explain that the solution satisfies all requisite symmetry and electron coalescence constraints of …

Computational Analysis Of Proton Conductivity Factors In Grotthuss-Style Mechanisms, Brock Dyer

Physics and Astronomy Honors Papers

The mechanism and fundamental molecular properties involved in proton conduction are discussed. Four calculable properties are presented: the proton affinity, binding energy (between protonated and neutral forms), intramolecular tautomerization barrier, and proton hopping barrier. An overview of the computational methods used in this thesis, including an introduction to the many-body Schrödinger equation and Density Functional Theory, as well as a look at Plane-Wave Density Functional Theory and Gaussian-Type Orbital Density Functional Theory are presented. 4,5-dimethyl-[1,2,3]-triazole is used as a model system, with 10 variations being generated with varying amounts and positions of fluorine substitution on the methyl groups. Preliminary calculations …

Quantum-Mechanical Definition Of The Classical Scalar Potential In Schrödinger-Pauli And Schrödinger Theory, Viraht Sahni

Publications and Research

According to the Bohr correspondence principle, the external temporal scalar potential in the classical equation of motion is replicated in quantum theory as a multiplicative operator. An equivalent quantum-mechanical definition of the scalar potential in Schrödinger-Pauli/Schrödinger theory is provided. The potential is a known universal functional of the wave function. At each instant of time, it is the work done in a conservative “classical” field representative of internal properties of the system: Pauli and Coulomb correlations, kinetic effects, the density, the Lorentz force, an internal magnetic component, and the current density response. The Hamiltonians are thus rewritten in a …

Entangled Photoelectron Attosecond Spectroscopy, Jonathan Sar-Shalom

Honors Undergraduate Theses

In this thesis we propose an interferometric scheme to retrieve the dynamics of an electron wave packet emitted from two distinct residual photo-ion channels in the ionization of an atom by an ultra-short UV pulse. EPAS (Entangled-Photoelectron Attosecond Spectroscopy) works by having a non-overlapping UV and few-cycle IR pulse, where the IR is tuned near the transition frequency between two electronic bound states of the photo-ion. Using a time-dependent simulation based on a two-channel atomic model, supported by a perturbative approach, we were able to compute the resulting interference in the angular distribution of the photoelectron and retrieve the energy-dependent …

Interactions And Applications Of Optical Angular Momentum In Magneto-Optical Material, Seth R. Nelson

Dissertations, Master's Theses and Master's Reports

This dissertation explores the interactions and applications of optical angular momentum within magneto-optical materials. Beginning with a theoretical and experimental analysis of multiple reflection and refraction phenomena within magneto-optical material. We derive and verify the dependence of refractive indices on optical spin angular momentum and magneto-optical magnetization, resulting in nonreciprocal elliptical and linear polarization beam splitting effects and wavevector discretization. We fabricate a magnetless slab waveguide isolator with minimal optical loss. Extending our study to optical orbital angular momentum, we introduce a perturbation to the electronic transition model in bismuth-substituted iron garnets. We demonstrate that this perturbation leads to nonreciprocal …

Periodic Trends In The Electronic And Magnetic Structure Of Superatomic 3d Transition Metal Chalcogenide Clusters, Gabriel Bohannon

Theses and Dissertations

We have systematically investigated the electronic structure of octahedral transition metal chalcogenide clusters, TM₆S₈(CO)₆, in which the transition metal atoms are from the 3d series in order to identify if periodic properties emerge. We were motivated by the identification of closed electronic shells with electron counts of 96, 100 and 114 in similar clusters from the 4d and 5d transition metal series. Further motivation was the finding of a dual-shell closing in the Fe₆S₈(CN)₆^5- cluster. This cluster is stabilized with a large spin magnetic moment due to the …

Scalable Methods For Performant Control Of Hyperfine Qubits In Atoms And Ions, Matthew N. H. Chow

Physics & Astronomy ETDs

Qubits encoded within internal energy levels of atoms and ions have been used to demonstrate high-performance primitives of quantum computing for small numbers of qubits. Yet, the path to achieving sufficient size and fidelity for useful fault-tolerant quantum computation remains daunting. In this dissertation, I present several techniques I developed as steps along this path. These results include high-fidelity, low-loss detection for alkali atoms in optical tweezers, crosstalk-mitigated parallel one-qubit gates, robust entangling gates on trapped ions, and leakage-to-erasure conversion for non-destructive detection of atom loss errors. Through this collection of techniques, I have sought to make full use of …

Experimental Characterization, Computational Investigation, And Structure-Property–Activity Relationship Studies Of Nickel Ferrite Nanostructures, Ali Ben Ahmed

Polytechnic Journal

Intending to predict the multifunctionality of Nickel ferrite in several technological and medical fields, we have prepared nickel ferrite nanostructure by coprecipitation method. X-ray Diffraction (XRD) is used to determine the crystalline structure and phase composition of materials by analyzing the pattern of X-rays scattered by the atoms within the material. Fourier Transform Infrared Spectroscopy (FTIR) provides information about a material's chemical bonds and functional groups by analyzing how it absorbs infrared light at various wavelengths. Scanning Electron Microscopy (SEM) offers high-resolution images of the material's surface morphology and texture by scanning it with a focused beam of electrons. Transmission …

Super-Resolution Magnetic Microscopy And Earth’S Field Magnetometry With Color Centers In Diamond, Nazanin Mosavian

Optical Science and Engineering ETDs

In recent years, the negatively charged nitrogen- vacancy (NV) center has emerged as a promising solid-state color center capable of measuring magnetic fields with high sensi- tivity and spatial resolution under ambient conditions. In this thesis I will discuss how we perform super resolution magnetic microscopy and acquire magnetic field images of nanoparticle samples at 100 nm resolution. I will explain how 3D flux concentrators increase magnetic field amplitude and allows us to measure vector component magnetic fields as low as 50 µT with a diamond magnetometer, without the use of an additional bias magnetic field. I also describe how …

Thermal Phase Fluctuations In Narrow Superfluid Rings, Parth Sabharwal

Dartmouth College Ph.D Dissertations

Remarkable advances have been made in the past decade in the ability to control superfluids in circuit-like configurations. Especially notable are the improvements in the initialization, stabilization and measurement of the circulation of superfluids in geometries with periodic boundary conditions, such as rings. This has significant implications for applications as rotation sensors, magnetometers, and in the emerging field of atomtronics. As the push towards studying supercurrents in lower dimensions and higher aspect ratios continues, in order to realize idealized experimental conditions and explore unusual quantum phases, phase fluctuations become increasingly pronounced, with the potential to destroy long-range order. In this …

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM Month

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …

Design Of Long-Distance Entanglement Distribution Protocols For Quantum Networks, Stav Haldar

LSU Doctoral Dissertations

Future quantum technologies such as quantum communication, quantum sensing, and distributed quantum computation, will rely on networks of shared entanglement between spatially separated nodes. Distributing entanglement between these nodes, especially over long distances, currently remains a challenge, due to limitations resulting from the fragility of quantum systems, such as photon losses, non-ideal measurements, and quantum memories with short coherence times. In the absence of full-scale fault-tolerant quantum error correction, which can in principle overcome these limitations, we should understand the extent to which we can circumvent these limitations. In this work, we provide improved protocols and policies for entanglement distribution …

Coherent Backscattering Under Conditions Of Electromagnetically Induced Transparency In Ultracold Rubidium, Joshua D. Carter

Physics Theses & Dissertations

This dissertation presents experimental results of coherent backscattering of light in an ultracold ensemble of rubidium atoms confined in a magneto optical trap under conditions of electromagnetically induced transparency (EIT) in a cascade-type system. Electromagnetically induced transparency was investigated experimentally in both a counterpropagating and orthogonal laser geometry and compared to theory. The experimental results were largely in good agreement with theory. Coherent backscattering was then measured with and without an EIT control field present to investigate the modification, if any, that EIT has on the enhancement of the coherent backscattering cone. The results indicated that the electromagnetically induced transparency …

Defect-Free Nanowelding Of Bilayer Snse Nanoplates, Jing-Rong Ji, John W. D. Villanova, Salvador Barraza-Lopez, Stuart S. P. Parkin, Kai Chang

Physics Faculty Publications and Presentations

Nanowelding is a bottom-up technique to create custom-designed nanostructures and devices beyond the precision of lithographic methods. Here, a new technique is reported based on anisotropic lubricity at the van der Waals interface between monolayer and bilayer SnSe nanoplates and a graphene substrate to achieve precise control of the crystal orientation and the interface during the welding process. As-grown SnSe monolayer and bilayer nanoplates are commensurate with graphene's armchair direction but lack commensuration along graphene's zigzag direction, resulting in a reduced friction along that direction and a rail-like, 1D movement that permits joining nanoplates with high precision. This way, molecular …

Optical Transport Of Ultracold Atoms, David Vera

Undergraduate Honors Theses

At temperatures near absolute zero, bosons form a macroscopic quantum state that can be manipulated and imaged in a very controlled and tunable way. To reach these extreme temperatures near absolute zero, advanced methods in cooling, including laser and evaporative cooling, must be used. In addition to these techniques for cooling, atoms must also be held up against the constant pull of gravity, so additional trapping techniques using lasers and magnets are used. In our lab at University of San Diego, we are implementing a tunable lens system (TLS) to optically transfer atoms to a more optically accessible location. A …

Entanglement With Neutral Atoms In The Simulation Of Nonequilibrium Dynamics Of One-Dimensional Spin Models, Anupam Mitra

Physics & Astronomy ETDs

Quantum entanglement is a key ingredient for quantum information processing with capabilities beyond that of classical computation. We study the generation and role of entanglement in the dynamics of spin-1/2 models, both for the design of quantum gates for general-purpose quantum computation and for quantum simulation of interacting spin models. We introduce the neutral atom Mølmer-Sørensen gate, involving rapid adiabatic Rydberg dressing interleaved in a spin-echo sequence. We show its robustness to quasi-static experimental imperfections and favorable scaling with the time-energy scales of Rydberg-mediated entanglement generation. In quantum simulation, we consider critical behavior in quench dynamics of transverse field Ising …

The Rubidium Magneto-Optical Trap: Designing A Robust System For Measurement & Control, Thomas Melody

Honors Program Theses and Projects

This thesis is a culmination of our efforts to construct a robust and flexible opto-mechanical system to fully deliver and control all of the parameters related to the required laser wavelength, polarization, power, beam size, and directionality for both the pump and the re-pump laser beams, delivered from two different lasers, necessary for neutral-atom laser trapping and cooling. This is an extension of the neutral Rubidium Magneto-Optical Trap (MOT) at BSU which afford a macroscopic scale collection of cold atoms where the effective governing laws of physics are quantum in nature rather than classical. My predecessors had done work on …

Development Of A High-Resolution Mid-Infrared Spectroscopy Apparatus For The Study Of Methane And Other Astrochemical Molecules., S M Shah Riyadh

Electronic Theses and Dissertations

This research documents steps towards building a novel spectroscopic technique, namely, cavity-enhanced double-resonance (CEDR) spectroscopy, for investigating methane (CH₄) and other molecules with significance in astrochemistry. These efforts focus on tackling the complexities of their ro-vibrational energy levels and the inefficiencies in analyzing vibrational spectra, particularly for molecules with high symmetry and strong intramolecular interactions. In the CEDR spectroscopy, the first photon, generated by a continuous-wave optical parametric oscillator (CW-OPO) locked to a Doppler-free saturation absorption line, excites the molecule from its ground level to a selected excited ro-vibrational (rotational-vibrational) level, e.g., that of the asymmetric CH-stretch mode. …

Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver, Robert Beattie-Rossberg

Electrical and Computer Engineering ETDs

A twelve-brick air insulated linear transformer driver (LTD) was characterized by charging to voltages ranging from 30 to 70 kV and delivering energy to two separate resistive loads. Various plasma diagnostics were built and fielded with an emphasis on the design, implementation and analysis of a Mach Zehnder interferometer, a moiré deflectometer and a spectroscopy system providing information on the temporal evolution of plasma electron density and atomic composition. Rogowski coils, XRD radiation detectors, framing camera images and time integrated DSLR images are used to further understand load conditions where current data, x ray radiation data, velocity data and instability …

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM for Success Showcase

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …