Quantum Physics Commons^™

Frustrated Quantum Magnetism: The Interplay Of Isotropic And Anisotropic Interactions With Application To Α-Rucl3, Evan M. Wilson

UNF Graduate Theses and Dissertations

We investigate how anisotropic spin interactions, including Dzyaloshinskii–Moriya and Kitaev terms, manifest across quantum spin systems ranging from a single S = 1/2 dimer to molecular spin clusters and layered magnetic materials. Beginning with an exact analysis of the spin dimer, we demonstrate how singlet–triplet mixing induced by Dzyaloshinskii–Moriya interaction directly influences both thermodynamic observables and inelastic neutron scattering spectra. These microscopic fingerprints are then extended to trimer, tetramer, and tetrahedron geometries, where field-induced phase transitions and heat capacity anomalies reveal the interplay between isotropic Heisenberg and anisotropic Kitaev exchanges. In the frustrated zigzag honeycomb lattice, we show that a …

A New Form Of Soft Supersymmetry Breaking?, Scott Chapman

Mathematics, Physics, and Computer Science Faculty Articles and Research

Starting with a supersymmetric U(N) × U(N) gauge theory built in N = 1 superspace, a nonsupersymmetric theory is obtained by “twisting” the gauginos into a different representation of the group than the gauge bosons. Despite the fact that this twisting breaks supersymmetry, it is still possible to construct an action that is holomorphic and invariant to local “twisted” gauge transformations in superspace. It is conjectured that these two properties may allow the theory to be free of quadratic divergences to all orders, despite a lack of supersymmetry. An explicit calculation shows that the theory is free of quadratic divergences …

Compact Control System For Superconducting Qubits, Santiago Lopez

The Journal of Purdue Undergraduate Research

No abstract provided.

Exploring The Accuracy Of Interferometric Quantum Measurements Under Conservation Laws, Nicolò Piccione, Maria Maffei, Andrew N. Jordan, Kater W. Murch, Alexia Auffèves

Mathematics, Physics, and Computer Science Faculty Articles and Research

A (target) quantum system is often measured through observations performed on a second (meter) system to which the target is coupled. In the presence of global conservation laws holding on the joint meter-target system, the Wigner-Araki-Yanase theorem and its generalizations predict a lower bound on the measurement’s error (Ozawa’s bound). While practically negligible for macroscopic meters, it becomes relevant for microscopic ones. Here, we propose a simple interferometric setup, arguably within reach of present technology, in which a flying particle (a microscopic quantum meter) is used to measure a qubit by interacting with it in one arm of the interferometer. …

Predicting Chaotic Systems With Quantum Echo-State Networks, Erik Connerty, Ethan N. Evans, Gerasimos Angelatos, Vignesh Narayanan

Publications

Recent advancements in artificial neural networks have enabled impressive tasks on classical computers, but they demand significant computational resources. While quantum computing offers potential beyond classical systems, the advantages of quantum neural networks (QNNs) remain largely unexplored. In this work, we present and examine a quantum circuit (QC) that implements and aims to improve upon the classical echo-state network (ESN), a type of reservoir-based recurrent neural networks (RNNs), using quantum computers. Typically, ESNs consist of an extremely large reservoir that learns high-dimensional embeddings, enabling prediction of complex system trajectories. Quantum echo-state networks (QESNs) aim to reduce this need for prohibitively …

Charge Transport In Two Dimensional Systems With Arbitrary Rashba And Dresselhaus Interactions, Abhishek Khanal

All Dissertations

In this thesis we discuss two different transport phenomena that occur in a two-dimensional electron system endowed with linear Rashba and Dresselhaus spin-orbit interactions of arbitrary values. First, in a semiclassical formalism we calculate the non-linear charge currents that appear in response to the simultaneous application of in-plane electric and magnetic fields. Working in a rotated system of coordinates that introduces $\alpha \pm \beta$ as effective couplings on perpendicular directions, we formulate a transport theory that relies on a second order distribution function derived in a local energy approximation and on chiral dependent relaxation times to show that the currents …

Fast Neutron & Gamma-Ray Scintillation And Broadband Photoluminescence From Gallium Nitride & Gallium Oxide: Developing Radiation-Hard Diagnostic Platforms, Daniel Jesus Valdes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Integrated scintillation and electronics processing materials are of critical importance in environments exposed to high levels of radiation, such as nuclear fusion diagnostics and space missions. This dissertation focuses on the radiation detection capabilities of gallium oxide (Ga2O3) and gallium nitride (GaN), exploring their responses to fast neutrons and gamma rays. Using high-energy neutron beam facilities at Los Alamos Neutron Science Center (LANSCE) Flight Path 4FP60R, we exposed both Ga2O3 and GaN crystals to neutron irradiation spanning an energy spectrum ranging from 1 to 400 MeV. A Pi-Max 4 fast-gated Intensified CCD (ICCD) camera captured the transient scintillation responses for …

Quantum Visual Feature Encoding Revisited, Xuan-Bac Nguyen, Hoang-Quan Nguyen, Hugh Churchill, Samee U. Khan, Khoa Luu

Computer Science and Computer Engineering Faculty Publications and Presentations

Although quantum machine learning has been introduced for a while, its applications in computer vision are still limited. This paper, therefore, revisits the quantum visual encoding strategies, the initial step in quantum machine learning. Investigating the root cause, we uncover that the existing quantum encoding design fails to ensure information preservation of the visual features after the encoding process, thus complicating the learning process of the quantum machine learning models. In particular, the problem, termed the “Quantum Information Gap” (QIG), leads to an information gap between classical and corresponding quantum features. We provide theoretical proof and practical examples with visualization …

Separating A Particle's Mass From Its Momentum, Mordecai Waegell, Jeff Tollaksen, Yakir Aharonov

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Quantum Cheshire Cat experiment showed that when weak measurements are performed on pre- and post-selected system, the counterintuitive result has been obtained that a neutron is measured to be in one place without its spin, and its spin is measured to be in another place without the neutron. A generalization of this effect is presented with a massive particle whose mass is measured to be in one place with no momentum, while the momentum is measured to be in another place without the mass. The new result applies to any massive particle, independent of its spin or charge. A …

High-Coherence Kerr-Cat Qubit In 2d Architecture, Ahmed Hajr, Bingcheng Qing, Ke Wang, Gerwin Koolstra, Zahra Pedramrazi, Ziqi Kang, Larry Chen, Long B. Nguyen, Christian Jünger, Noah Goss, Irwin Huang, Bibek Bhandari, Nicholas E. Frattini, Shruti Puri, Justin Dressel, Andrew N. Jordan, David I. Santiago, Irfan Siddiqi

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Kerr-cat qubit is a bosonic qubit in which multiphoton Schrödinger cat states are stabilized by applying a two-photon drive to an oscillator with a Kerr nonlinearity. The suppressed bit-flip rate with increasing cat size makes this qubit a promising candidate to implement quantum error correction codes tailored for noise-biased qubits. However, achieving strong light-matter interactions necessary for stabilizing and controlling this qubit has traditionally required strong microwave drives that heat the qubit and degrade its performance. In contrast, increasing the coupling to the drive port removes the need for strong drives at the expense of large Purcell decay. By …

Measurement Of Multi-Jet Ratios In The Atlas Experiment, Zahra Farazpay

Doctoral Dissertations

This dissertation presents a comprehensive study of multi-jet cross-section ratios using proton-proton collision data collected by the ATLAS detector during Run 2 of the Large Hadron Collider (LHC) at a center-of-mass energy of √ s = 13TeV. By examining these ratios across different energy scales, the analysis provides valuable insights into the running of the strong coupling constant, αs, a fundamental parameter in Quantum Chromodynamics (QCD) that dictates the strength of the strong interaction. The running of αs—its variation with energy—is crucial for understanding QCD, yet it remains one of the least precisely known aspects of the theory. In this …

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 …

Quality Infrastructure Empowering Collaborative Innovation In Quantum Information Industry: Mechanism, Demand, And Path, Leilei Zhang, Jian Kang, Zhou He

Bulletin of Chinese Academy of Sciences (Chinese Version)

Against the backdrop of intensified global competition in quantum information, the synergistic effectiveness of quality infrastructure, as a basic system supporting industrial innovation, is directly related to the industrialization process of quantum technology. At present, subdivided industries such as quantum computing, quantum communication, and quantum precision measurement have begun to take shape, and key technologies and core products have entered a critical period of transition from scientific and technological innovation results to industrialization, and the demand for quality infrastructure is becoming increasingly prominent. This study explores the co-evolution mechanism of quality infrastructure driven by industrial innovation and analyzes the coupling …

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 …

An Introduction To The Time-Independent Schrödinger Equation And Methods To Solve It, Vu Giang, Alex Gnech

OUR Journal: ODU Undergraduate Research Journal

The Time-Independent Schrödinger Equation is a linear elliptic PDE that describes quantum-mechanical systems. Its significance in the science of submicroscopic phenomena, particularly quantum mechanics, is as central as Newton’s laws of motion are to classical mechanics. This study uses various methods, including novel neural networks and finite difference schemes, to solve the one-dimensional two-body equation.

Long-Distance Photon-Mediated And Short-Distance Entangling Gates In Three-Qubit Quantum Dot Spin Systems, Nooshin M. Estakhri, Ada Warren, Sophia E. Economou, Edwin Barnes

Engineering Faculty Articles and Research

Superconducting resonator couplers will likely become an essential component in modular semiconductor quantum dot (QD) spin qubit processors, as they help alleviate crosstalk and wiring issues as the number of qubits increases. Here, we focus on a three-qubit system composed of two modules: a two-electron triple QD resonator coupled to a single-electron double QD. Using a combination of analytical techniques and numerical results, we derive an effective Hamiltonian that describes the three-qubit logical subspace and show that it accurately captures the dynamics of the system. We examine the performance of short-range and long-range entangling gates, revealing the effect of a …

Optimal Radar Ranging Pulse To Resolve Two Reflectors, Andrew N. Jordan, John C. Howell, Achim Kempf, Shunxing Zhang, Derek White

Mathematics, Physics, and Computer Science Faculty Articles and Research

Previous work established fundamental bounds on subwavelength resolution for the radar range resolution problem, called superradar [Phys. Rev. Appl. 20, 064046 (2023)]. In this work, we identify the optimal waveforms for distinguishing the range resolution between two reflectors of identical strength, leveraging results in quantum metrology. We discuss both the unnormalized optimal waveform as well as the best square-integrable pulse and their variants. Using orthogonal function theory, we give an explicit algorithm to optimize the wave pulse in finite time to have the best performance. We also explore range resolution estimation with unnormalized waveforms with multiparameter methods to …

Design, Characterization, And Simulation Of A 2d Dual-Rail Quantum Processor, Diego Barrutia

Dartmouth College Master’s Theses

Bosonic systems, such as three-dimensional (3D) λ/4 coaxial cavities and two-dimensional (2D) λ/2 coplanar waveguide (CPW) resonators, are quantum harmonic oscillators that encode information in phase space, offering a hardware-efficient route toward quantum error correction and simulation in superconducting circuits. In this thesis, we present the design, characterization, and simulation of a dual-rail processor constructed with a 2D λ/2 coplanar waveguide resonators, demonstrating a percent error between experimental and analytical results within a range of 3.31% - 13.16%. The analytical results exhibit high precision but lower accuracy relative to experimental measurements. By integrating both closed-source and open-source software tools, we …

Shear Viscosity Of Quasi One-Dimensional Bec Tubes And Entanglement Negativity Conditions, Camilla Polvara

Dissertations, Theses, and Capstone Projects

Shear Viscosity of Quasi One-dimensional BEC Tubes

We consider layered Bose-Einstein condensates interacting via contact intra-condensate interacions and dipolar inter-condensate potentials, both of which dominate intercondensate tunneling (which we neglect for simplicity). For this system, we compute the normal modes, we study its localization properties by numerically computing the inverse participation ratio, and we compute the inter-tube shear viscosity.

Entanglement Negativity Conditions

This project explores bounds on entanglement negativity using operator inequalities, building on the results of [1]. We are looking for a way to quantify entanglement, as an alternative to calculating the full negativity, which would otherwise require the …