Non-Inertial Quantum Clock Frames Lead To Non-Hermitian Dynamics, 2022 Bar-Ilan University

#### Non-Inertial Quantum Clock Frames Lead To Non-Hermitian Dynamics, Ismael L. Paiva, Amit Te'eni, Bar Y. Peled, Eliahu Cohen, Yakir Aharonov

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

The operational approach to time is a cornerstone of relativistic theories, as evidenced by the notion of proper time. In standard quantum mechanics, however, time is an external parameter. Recently, many attempts have been made to extend the notion of proper time to quantum mechanics within a relational framework. Here, we use similar ideas combined with the relativistic mass-energy equivalence to study an accelerating massive quantum particle with an internal clock system. We show that the ensuing evolution from the perspective of the particle’s internal clock is non-Hermitian. This result does not rely on specific implementations of the clock. As …

Compilation Optimizations To Enhance Resilience Of Big Data Programs And Quantum Processors, 2022 Louisiana State University and Agricultural and Mechanical College

#### Compilation Optimizations To Enhance Resilience Of Big Data Programs And Quantum Processors, Travis D. Lecompte

*LSU Doctoral Dissertations*

Modern computers can experience a variety of transient errors due to the surrounding environment, known as soft faults. Although the frequency of these faults is low enough to not be noticeable on personal computers, they become a considerable concern during large-scale distributed computations or systems in more vulnerable environments like satellites. These faults occur as a bit flip of some value in a register, operation, or memory during execution. They surface as either program crashes, hangs, or silent data corruption (SDC), each of which can waste time, money, and resources. Hardware methods, such as shielding or error correcting memory (ECM), …

Symmetry Breaking Effects In Low-Dimensional Quantum Systems, 2022 University of Massachusetts Amherst

#### Symmetry Breaking Effects In Low-Dimensional Quantum Systems, Ke Wang

*Doctoral Dissertations*

Quantum criticality in low-dimensional quantum systems is known to host exotic behaviors. In quantum one-dimension (1D), the emerging conformal group contains infinite generators, and conformal techniques, e.g., operator product expansion, give accurate and universal descriptions of underlying systems. In quantum two-dimension (2D), the electronic interaction causes singular corrections to Fermi-liquids characteristics. Meanwhile, the Dirac fermions in topological 2D materials can greatly enrich emerging phenomena. In this thesis, we study the symmetry-breaking effects of low-dimensional quantum criticality. In 1D, we consider two cases: time-reversal symmetry (TRS) breaking in the Majorana conformal field theory (CFT) and the absence of conformal symmetry in …

Reservoir Engineering Of Multi-Photon States In Circuit Quantum Electrodynamics, 2022 University of Massachusetts Amherst

#### Reservoir Engineering Of Multi-Photon States In Circuit Quantum Electrodynamics, Jeffrey M. Gertler

*Doctoral Dissertations*

The field of experimental quantum information has made significant progress towards useful computation but has been handicapped by the dissipative nature of physical qubits. Except for unwieldy and unrealized topological qubits, all quantum information systems experience natural dissipation, which limits the time scale for useful computation. However, this same dissipation, which induces errors requiring quantum error correction (QEC), can be used as a resource to perform a variety of important and unrealized tasks. In this thesis I discuss research into three uses of dissipation: manifold stabilization, state transfer, and QEC. With reservoir engineering, these tasks can be addressed in an …

Anomalous Transport, Quasiperiodicity, And Measurement Induced Phase Transitions, 2022 University of Massachusetts Amherst

#### Anomalous Transport, Quasiperiodicity, And Measurement Induced Phase Transitions, Utkarsh Agrawal

*Doctoral Dissertations*

With the advent of the noisy-intermediate scale quantum (NISQ) era quantum computers are increasingly becoming a reality of the near future. Though universal computation still seems daunting, a great part of the excitement is about using quantum simulators to solve fundamental problems in fields ranging from quantum gravity to quantum many-body systems. This so-called second quantum revolution rests on two pillars. First, the ability to have precise control over experimental degrees of freedom is crucial for the realization of NISQ devices. Significant progress in the control and manipulation of qubits, atoms, and ions, as well as their interactions, has not …

Two Roads To Retrocausality, 2022 Chapman University

#### Two Roads To Retrocausality, Emily Adlam

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

In recent years the quantum foundations community has seen increasing interest in the possibility of using retrocausality as a route to rejecting the conclusions of Bell’s theorem and restoring locality to quantum physics. On the other hand, it has also been argued that accepting nonlocality leads to a form of retrocausality. In this article we seek to elucidate the relationship between retrocausality and locality. We begin by providing a brief schema of the various ways in which violations of Bell’s inequalities might lead us to consider some form of retrocausality. We then consider some possible motivations for using retrocausality to …

Tabletop Experiments For Quantum Gravity Are Also Tests Of The Interpretation Of Quantum Mechanics, 2022 Chapman University

#### Tabletop Experiments For Quantum Gravity Are Also Tests Of The Interpretation Of Quantum Mechanics, Emily Adlam

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

Recently there has been a great deal of interest in tabletop experiments intended to exhibit the quantum nature of gravity by demonstrating that it can induce entanglement. In order to evaluate these experiments, we must determine if there is any interesting class of possibilities that will be convincingly ruled out if it turns out that gravity can indeed induce entanglement. In particular, since one argument for the significance of these experiments rests on the claim that they demonstrate the existence of superpositions of spacetimes, it is important to keep in mind that different interpretations of quantum mechanics may make different …

Characterization Of Superconducting Hardware For Implementing Quantum Stabilizers, 2022 Syracuse University

#### Characterization Of Superconducting Hardware For Implementing Quantum Stabilizers, Kenneth Richard Dodge

*Dissertations - ALL*

Superconducting qubits are one of the leading approaches being investigated for building a scalable quantum computer. In the presence of external noise and perturbations plus local microscopic fluctuations and dissipation in the qubit environment, arbitrary quantum states will decohere, leading to bit-flip and phase-flip errors of the qubit. In order to build a fault-tolerant quantum computer that can preserve and process quantum information in the presence of noise and dissipation, one must implement some form of quantum error correction. Stabilizer operations are at the heart of quantum error correction and are typically implemented in software-controlled entangling gates and measurements of …

Classification Of Pixel Tracks To Improve Track Reconstruction From Proton-Proton Collisions, 2022 Southern Methodist University

#### Classification Of Pixel Tracks To Improve Track Reconstruction From Proton-Proton Collisions, Kebur Fantahun, Jobin Joseph, Halle Purdom, Nibhrat Lohia

*SMU Data Science Review*

In this paper, machine learning techniques are used to reconstruct particle collision pathways. CERN (Conseil européen pour la recherche nucléaire) uses a massive underground particle collider, called the Large Hadron Collider or LHC, to produce particle collisions at extremely high speeds. There are several layers of detectors in the collider that track the pathways of particles as they collide. The data produced from collisions contains an extraneous amount of background noise, i.e., decays from known particle collisions produce fake signal. Particularly, in the first layer of the detector, the pixel tracker, there is an overwhelming amount of background noise that …

Watching The Clocks: Interpreting The Page-Wootters Formalism And The Internal Quantum Reference Frame Programme, 2022 Chapman University

#### Watching The Clocks: Interpreting The Page-Wootters Formalism And The Internal Quantum Reference Frame Programme, Emily Adlam

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

We discuss some difficulties that arise in attempting to interpret the Page–Wootters and Internal Quantum Reference Frames formalisms, then use a ‘final measurement’ approach to demonstrate that there is a workable single-world realist interpretation for these formalisms. We note that it is necessary to adopt some interpretation before we can determine if the ‘reference frames’ invoked in these approaches are operationally meaningful, and we argue that without a clear operational interpretation, such reference frames might not be suitable to define an equivalence principle. We argue that the notion of superposition should take into account the way in which an instantaneous …

Methods For Bioconjugation Of Biochemical Sensors Based On Metallic Nanoparticles, 2022 University of Alabama in Huntsville

#### Methods For Bioconjugation Of Biochemical Sensors Based On Metallic Nanoparticles, Jacob Rolin

*Summer Community of Scholars Posters (RCEU and HCR Combined Programs)*

No abstract provided.

Control Of Nonlinear Properties Of Van Der Waals Materials, 2022 The Graduate Center, City University of New York

#### Control Of Nonlinear Properties Of Van Der Waals Materials, Rezlind Bushati

*Dissertations, Theses, and Capstone Projects*

Van der Waals materials are a broad class of materials that exhibit unique optoelectronic properties. They provide a rich playground for which they can be integrated into current on-chip devices due to their nanometer-scale size, and be utilized for studying fundamental physics. Strong coupling of emitters to microcavities provides many opportunities for new exotic physics through the formation of hybrid quasi-particles exciton-polaritons. This thesis

focuses on exploring and enhancing nonlinearity of van der Waals materials through strongly coupling to microcavities. By taking advantage of the stacking order of TMDs, we show intense second-harmonic generation from bulk, centrosymmetric TMD systems. In …

Wideband And Relativistic Superradiance In Astrophysics, 2022 The University of Western Ontario

#### Wideband And Relativistic Superradiance In Astrophysics, Christopher M. Wyenberg

*Electronic Thesis and Dissertation Repository*

In the quantum phenomenon of superradiance (SR) a population of inverted particles evolves, through its interaction with the quantized vacuum radiation field, into a highly entangled state capable of generating much greater radiative emission than predicted by the independent spontaneous decay of its constituent particles. The phenomenon has recently been applied to transient astrophysical processes but has thus far been restricted to particles sharing a common velocity. This thesis researches the effects of astrophysical velocity distributions upon SR, which are distinct from conventional regimes of the quantum optics literature in that they may possess extremely wide bandwidths, turbulent statistical properties, …

Magnetic Skyrmions Unwrapped, 2022 University of Nebraska - Lincoln

#### Magnetic Skyrmions Unwrapped, Alexey Kovalev

*Alexey Kovalev Papers*

Experiments with chiral magnets may hold the key to a better understanding of fundamental aspects of transformations between different skyrmionic states, necessary for magnetic memory and logic applications to become a reality.

** **With the aim of developing computing devices that operate with low power dissipation, scientists have been pursuing the idea of encoding information in magnetic states. Specifically, skyrmions, which can be thought of as whirl-like states of magnetic moments, are promising candidates for this purpose. The advantage of skyrmions lies in their topological protection, a property implying that only a ‘global’ system modification can erase a skyrmion. Realizations of …

The 'Quantal Newtonian' First Law: A Complementary Perspective To The Stationary-State Quantum Theory Of Electrons, 2022 CUNY Brooklyn College

#### The 'Quantal Newtonian' First Law: A Complementary Perspective To The Stationary-State Quantum Theory Of Electrons, Viraht Sahni

*Publications and Research*

A complementary perspective to the Göttingen-Copenhagen interpretation of stationary-state quantum theory of electrons in an electromagnetic field is described. The perspective, derived from Schrödinger-Pauli theory, is that of the individual electron via its equation of motion or ‘Quantal Newtonian’ First Law. The Law is in terms of ‘classical’ fields experienced by each electron: the sum of the external and internal fields vanishes. The external field is a sum of the electrostatic and Lorentz fields. The internal field is a sum of fields’ representative of Pauli and Coulomb correlations; kinetic effects; electron density; and internal magnetic component. The energy is obtained …

Characterizing The Single-Photon State: Quantum Physics Experiments With Single-Photon Sensitivity, 2022 Portland State University

#### Characterizing The Single-Photon State: Quantum Physics Experiments With Single-Photon Sensitivity, Sheldon Lee Field

*University Honors Theses*

Coincidence-counting and spontaneous parametric downconversion are central to introductory quantum mechanical experimentation but have remained largely out of reach of undergraduate physics instructors. This thesis summarizes the theory behind light polarization, spontaneous parametric downconversion, birefringent refractive indices, and an affordable self-contained photon coincidence counting unit (CCU). A method for implementing a CCU to demonstrate downconversion is presented, and empirical results are provided.

Overcoming Atmospheric Effects In Quantum Cryptography, 2022 University of Tennessee, Knoxville

#### Overcoming Atmospheric Effects In Quantum Cryptography, Brian Joseph Rollick

*Doctoral Dissertations*

Quantum Computers will have the potential to greatly assist us in problems such as searching, optimization and even drug discovery. Unfortunately, among these newfound capabilities is one which allows one to break RSA encryption in orders of magnitude less time. One promising countermeasure to secure our communication today and in the future is the one time pad, although it is very difficult to generate and distribute. Quantum Key Distribution offers a practical method for two authenticated parties to generate a key. Whereby the parties, Alice and Bob, share quantum states and use physical laws to place an upper bound on …

Quantum Computational Simulations For Condensed Matter Systems, 2022 University of Tennessee, Knoxville

#### Quantum Computational Simulations For Condensed Matter Systems, Trevor Alan Keen

*Doctoral Dissertations*

In condensed matter physics, and especially in the study of strongly correlated electron systems, numerical simulation techniques are crucial to determine the properties of the system including interesting phases of matter that arise from electron-electron interactions. Many of these interesting phases of matter, including but not limited to Mott-insulating materials and possibly high-temperature superconducting systems, can be modeled by the Hubbard model. Although it is one of the simplest models to include electron-electron interactions, it cannot be solved analytically in more than one dimension and thus numerical techniques must be employed. Although there have been great strides in classical numerical …

Optimization Of Quantum Circuits Using Spin Bus Multiqubit Gates For Quantum Dots, 2022 University of Texas at El Paso

#### Optimization Of Quantum Circuits Using Spin Bus Multiqubit Gates For Quantum Dots, Miguel Gonzalo Rodriguez

*Open Access Theses & Dissertations*

The current conventional method for designing quantum circuits is to employ a number of single- and two-qubit gates, which often necessitate a lengthy sequence, imposing severe constraints on quantum coherence and quantum circuit complexity. Coupling multiple spin qubits to a common spin chain can result in a generically multiqubit gate. It is demonstrated that the multiqubit gate can substantially reduce the depth of quantum circuits and establish multiqubit entanglement considerably more quickly.

Quantum Computing Simulation Of The Hydrogen Molecule System With Rigorous Quantum Circuit Derivations, 2022 Utah State University

#### Quantum Computing Simulation Of The Hydrogen Molecule System With Rigorous Quantum Circuit Derivations, Yili Zhang

*All Graduate Plan B and other Reports, Spring 1920 to Spring 2023*

Quantum computing has been an emerging technology in the past few decades. It utilizes the power of programmable quantum devices to perform computation, which can solve complex problems in a feasible time that is impossible with classical computers. Simulating quantum chemical systems using quantum computers is one of the most active research fields in quantum computing. However, due to the novelty of the technology and concept, most materials in the literature are not accessible for newbies in the field and sometimes can cause ambiguity for practitioners due to missing details.

This report provides a rigorous derivation of simulating quantum chemistry …