Quantum Physics Commons^™

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 …

Curved Spacetime In The Causal Set Approach To Quantum Gravity, Ayush Dhital

Honors Theses

Causal Set theory is an approach to quantum gravity. In this approach, the spacetime continuum is assumed to be discrete rather than continuous. The discrete points in a causal set can be seen as a continuum spacetime if they can be embedded in a manifold such that the causal structure is preserved. In this regard, a manifold can be constructed by embedding a causal set preserving causal information between the neighboring points. In this thesis, some of the fundamental properties of causal sets are discussed and the curvature and dimension information of Minkowski, de Sitter, and Anti-de Sitter spaces is …

Exploring Manifoldlike Causal Sets And Their Dimensions, Santosh Bhandari

Honors Theses

Causal Set Theory is an approach to quantum gravity that tries to replace the continuum spacetime structure of general relativity with the spacetime that has the property of discreteness and causality. From the standpoint of causal set theory, our spacetime is made up of discrete points that are causally related to one another. A causal set is said to be manifoldlike if it can be faithfully embedded in a Lorentzian manifold. In this thesis, some of the fundamental properties of causal sets are discussed. The first chapter is devoted to the historical background of quantum gravity with a discussion of …

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 …

Implications Of The Quantum Dna Model For Information Sciences, F. Matthew Mihelic

Faculty Publications

The DNA molecule can be modeled as a quantum logic processor, and this model has been supported by pilot research that experimentally demonstrated non-local communication between cells in separated cell cultures. This modeling and pilot research have important implications for information sciences, providing a potential architecture for quantum computing that operates at room temperature and is scalable to millions of qubits, and including the potential for an entanglement communication system based upon the quantum DNA architecture. Such a system could be used to provide non-local quantum key distribution that could not be blocked by any shielding or water depth, would …

Magnetic Vector Potential Manipulation Of Majorana Fermions In Dna Quantum Logic, F. Matthew Mihelic

Faculty Publications

In the quantum logic of the DNA molecule, electrons are held and conducted coherently as spinless Cooper pairs and are shielded from electromagnetic energy by a Faraday cage effect of the double lipid bilayer of the nuclear membrane. The magnetic vector potential generated by cellular depolarization can synchronize logical activity in portions of the DNA molecule by affecting spin directions of appropriately oriented spinless electrons via the Aharonov-Bohm effect, but is not blocked by that Faraday cage effect. Within the logically and thermodynamically reversible chiral enantiomeric symmetry of the deoxyribose moieties the decoherent transition of Cooper pair to Dirac pair …

Exploring Qcd Factorization At Moderate Energy Scales, Eric Alan Moffat

Physics Theses & Dissertations

Asymptotic freedom in QCD facilitates the use of partonic degrees of freedom over short distances, but physical processes are sensitive to a wide range of scales. Thus, it is necessary in QCD calculations to utilize a factorization scheme to separate a process into perturbative and non-perturbative factors. This separation relies on an assumption that one energy scale is infinitely larger than the other scales involved in the process. However, much experimental research in areas such as nucleon structure and quark-hadron duality occur at more moderate energy scales where that basic assumption may not be true but perturbative calculations should still …

Spectator Proton Detection And Reconstruction In Deep Inelastic D(E,EpS) Scattering, David Payette

Physics Theses & Dissertations

A Radial Time Projection Chamber (RTPC) was designed and installed in Jefferson Lab's Hall B as part of the BONuS12 (Barely Off-shell Nucleon Structure) experiment. The goal of BONuS12 is to accurately measure the structure function of the neutron by scattering 11 GeV electrons and detecting them with the CLAS12 spectrometer. Deuterium gas was used as an effective neutron target, and the new RTPC was used to detect low- momentum spectator protons. Protons follow a curved path in the 5 Tesla solenoid that is part of CLAS12, ionizing the He-CO2 gas in an annular drift region surrounding the target. These …

Optomechanical Quantum Entanglement, Kahlil Y. Dixon

LSU Doctoral Dissertations

As classical technology approaches its limits, exploration of quantum technologies is critical. Quantum optics will be the basis of various cutting-edge research and applications in quantum technology. In particular, quantum optics quite efficacious when applied to quantum networks and the quantum internet. Quantum Optomechanics, a subfield of quantum optics, contains some novel methods for entanglement generation. These entanglement production methods exploit the noise re-encoding process, which is most often associated with creating unwanted phase noise in optical circuits. Using the adapted two-photon formalism and experimental results, we simulate (in an experimentally viable parameter space) optomechanical entanglement generation experiments. These simulations …

Energy-Constrained Distinguishability Measures For Assessing Performance In Quantum Information Processing, Kunal Sharma

LSU Doctoral Dissertations

The aim of this thesis is to develop a framework for assessing performance in quantum information processing with continuous variables. In particular, we focus on quantifying the fundamental limitations on communication and computation over bosonic Gaussian systems. Due to their infinite-dimensional structure, we make a realistic assumption of energy constraints on the input states of continuous-variable (CV) quantum operations. Our first contribution is to show that energy-constrained distinguishability measures can be used to establish tight upper bounds on the communication capacities of phase-insensitive, bosonic Gaussian channels -- thermal, amplifier, and additive-noise channels. We then prove that an optimal Gaussian input …

Failed Attempt To Escape From The Quantum Pigeon Conundrum, Yakir Aharonov, Shrobona Bagchi, Justin Dressel, Gregory Reznik, Michael Ridley, Lev Vaidman

Mathematics, Physics, and Computer Science Faculty Articles and Research

A recent criticism by Kunstatter et al. [Phys. Lett. A 384, 126686 (2020)] of a quantum setup violating the pigeon counting principle [Aharonov et al. PNAS 113, 532 (2016)] is refuted. The quantum nature of the violation of the pigeonhole principle with pre- and postselection is clarified.

Applications Of Quantum Optics: From The Quantum Internet To Analogue Gravity, Anthony Brady

LSU Doctoral Dissertations

The aim of this thesis is to highlight applications of quantum optics in two very distinct fields: space-based quantum communication and the Hawking effect in analogue gravity. Regarding the former: We simulate and analyze a constellation of satellites, equipped with entangled photon-pair sources, which provide on-demand entanglement distribution ser- vices to terrestrial receiver stations. Satellite services are especially relevant for long-distance quantum-communication scenarios, as the loss in satellite-based schemes scales more favor- ably with distance than in optical fibers or in atmospheric links, though establishing quantum resources in the space-domain is expensive. We thus develop an optimization technique which balances …

Quantum Simulation Of Schrödinger's Equation, Mohamed Eltohfa

Capstone and Graduation Projects

Quantum computing is one of the promising active areas in physics research. This is because of the potential of quantum algorithms to outperform their classical counterparts. Grover’s search algorithm has a quadratic speed-up compared to the classical linear search. The quantum simulation of Schrödinger’s equation has an exponential memory save-up compared to the classical simulation. In this thesis, the ideas and tools of quantum computing are reviewed. Grover’s algorithm is studied and simulated as an example. Using the Qiskit quantum computing library, a code to simulate Schrödinger’s equation for a particle in one dimension is developed, simulated locally, and run …

Smart Quantum Technologies Using Photons, Narayan Bhusal

LSU Doctoral Dissertations

The technologies utilizing quantum states of light have been in the spotlight for the last two decades. In this regard, quantum metrology, quantum imaging, quantum-optical communication are some of the important applications that exploit fascinating quantum properties like quantum superposition, quantum correlations, and nonclassical photon statistics. However, the state-of-art technologies operating at the single-photon level are not robust enough to truly realize a reliable quantum-photonic technology.

In Chapter 1, I present a historical account of photon-based technologies. Furthermore, I discuss recent efforts and encouraging developments in the field of quantum-photonic technologies, and major challenges for the experimental realization of reliable …

Towards A General Framework For Practical Quantum Network Protocols, Sumeet Khatri

LSU Doctoral Dissertations

The quantum internet is one of the frontiers of quantum information science. It will revolutionize the way we communicate and do other tasks, and it will allow for tasks that are not possible using the current, classical internet. The backbone of a quantum internet is entanglement distributed globally in order to allow for such novel applications to be performed over long distances. Experimental progress is currently being made to realize quantum networks on a small scale, but much theoretical work is still needed in order to understand how best to distribute entanglement and to guide the realization of large-scale quantum …

Patrick Aidan Heelan’S The Observable: Heisenberg’S Philosophy Of Quantum Mechanics, Paul Downes

Research Resources

The publication of Patrick Aidan Heelan’s The Observable, with forewords from Michel Bitbol, editor Babette Babich and the author himself, offers a timely invitation to reconsider the relation between quantum physics and continental philosophy.

Patrick Heelan does so, as a contemporary of and interlocutor with Werner Heisenberg on these issues, as a physicist himself who trained with leading figures of quantum mechanics (QM), Erwin Schrödinger and Eugene Wigner. Moreover, Heelan highlights Heisenberg’s interest in phenomenology as ‘a friend and frequent visitor of Martin Heidegger’ (55). Written originally in 1970 and unpublished then for reasons Babich explicates in her foreword, …

Quantum Computing: Resolving Myths, From Physics To Metaphysics, Jacob R. Mandel

Physics

As the field of quantum computing becomes popularized, myths or misconceptions will inevitably come along with it. From the sci-fi genre to the casual usage of the term quantum, idealism begins to take over our projections of the technological future. But what are quantum computers? And what does quantum mean? How are they any different than the computers we use on an everyday basis? Will there be quantum computing smartphones? Are quantum computers just a faster version of conventional computing or a wholly new way of computing altogether? The objective of this paper is to resolve common myths or misconceptions …

Lorentz Violation In Neutrino Interactions, Pranav Jayaram Seetharaman

Physics

Both the Standard Model of particle physics and General Relativity require Lorentz symmetry as a fundamental building block. In this paper, we learn about a framework called the Standard Model Extension that allows us to determine how physical phenomenon would change if we deviated from Lorentz invariance in the Standard Model and General Relativity. We use the Standard Model Extension to analyze a specific high-energy, astrophysical neutrino interaction that is only possible if Lorentz symmetry can be broken. The interaction we look at is the decay of a neutrino into an electron-positron pair, which is not possible in conventional physics. …

Extracting The Number Of Short Range Correlated Nucleon Pairs From Inclusive Electron Scattering Data, R. Weiss, A. W. Denniston, J. R. Pybus, O. Hen, E. Piasetzky, A. Schmidt, L. B. Weinstein, N. Barnea

Physics Faculty Publications

The extraction of the relative abundances of short-range correlated (SRC) nucleon pairs from inclusive electron scattering is studied using the generalized contact formalism (GCF) with several nuclear interaction models. GCF calculations can reproduce the observed scaling of the cross-section ratios for nuclei relative to deuterium at high x_B and large Q², a₂ = (σ_A/A)/(σ_d/2). In the nonrelativistic instant-form formulation, the calculation is very sensitive to the model parameters and only reproduces the data using parameters that are inconsistent with ab initio many-body calculations. Using a light-cone GCF formulation significantly decreases this sensitivity …

Triplet 23S State Of A Quantum Dot In A Magnetic Field: A 'Quantal Newtonian' First Law Study, Marlina Slamet, Viraht Sahni

Publications and Research

The triplet 2³S state of a 2-electron 2-dimensional quantum dot in a magnetic field is studied via a complementary perspective of Schrödinger-Pauli theory. The perspective is that of the individual electron via its equation of motion or ‘Quantal Newtonian’ first law. According to the law, each electron experiences an external and internal field, the sum of which vanishes. The external field is the sum of the binding and Lorentz fields. The internal field is a sum of the electron-interaction, kinetic, differential density, and internal magnetic fields. The energy is expressed in integral virial form in terms of these …

Determination Of The Rydberg Constant From The Emission Spectra Of H And He+, Kyle D. Shaffer

Ramifications

Abstract

In this experiment, the Rydberg constants for the hydrogen atom and He⁺ were determined by analysis of the emission spectra of Hand He, respectively, in comparison to the principal quantum numbers of each transition. Using both a hydrogen and then a helium atomic lamp attached to a 0.5 m grating spectrometer and a photomultiplier detector (PMT), a change in voltage detected by the PMT can be paired with a corresponding wavelength passing through the spectrometer from each emission peak in the visible to ultraviolet range. The peaks acquired from this change in voltage were analyzed to find their …

Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, Robert J. Collison

Dissertations, Theses, and Capstone Projects

It is common knowledge that metals, alloys and pure elements alike, are lustrous and reflective, the more so when a metal surface is flat, polished, and free from oxidation and surface fouling. However, some metals reflect visible light, in the 380 nm to 740 nm range of wavelengths, much more strongly than others. In particular, some metals reflect wavelengths in certain portions of the ultraviolet (UV), visible, and near-infrared (NIR) regime, let us say 200 nm to 2000 nm, while absorbing light strongly in other segments of this range. There are several factors that account for this difference between various …

Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

The emerging field of plasmonics can lead to enhanced light-matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit …

Up-And-Coming Advances In Optical And Microwave Nonreciprocity: From Classical To Quantum Realm, Sergey V. Kutsaev, Alex Krasnok, Sergey N. Romanenko, Alexander Yu. Smirnov, Kirill Taletski, Vyacheslav P. Yakovlev

Advanced Science Research Center

Reciprocity is a fundamental physical principle that roots in the time-reversal symmetry of physical laws. It allows making predictions on any arbitrary complex system's response and operation and hence simplifies the analysis. However, there are many practical situations in which it is advantageous to break reciprocity, e.g., isolators preventing wave scattering back to lasers and generators, full-duplex systems for multiplexing transmission and receiving in the same channel, nonreciprocal cavity excitation, and protection of fragile states of superconductor quantum computers from thermal noise. The most widespread approach to time-reversal symmetry breaking and nonreciprocity based on magnetic field biasing suffers from bulkiness, …

Mutual Interaction Induced Multi-Particle Physics In Qed Systems – Cooperative Spontaneous Emission And Photonic Dimer Enhanced Two-Photon Excitation, Yao Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, the study of quantum electrodynamics (QED) in light-matter interactions has discovered various interesting phenomenons that orient many applications. However, due to the ambient entanglement among photons and atoms, few-particle dynamics remains challenging to analyze precisely and limits the progress in several fields. In few-particle systems, different number of atoms interacting with the light field generates drastically different results, even when there is only a single photon involved in the system. The interference between individual atom’s spontaneous emission wavefunctions can cooperatively alter the effective atom-light coupling strength. Depending on the spatial distance between individual of atoms and the …

On Conservation Laws In Quantum Mechanics, Yakir Aharonov, Sandu Popescu, Daniel Rohrlich

Mathematics, Physics, and Computer Science Faculty Articles and Research

Conservation laws are one of the most important aspects of nature. As such, they have been intensively studied and extensively applied, and are considered to be perfectly well established. We, however, raise fundamental question about the very meaning of conservation laws in quantum mechanics. We argue that, although the standard way in which conservation laws are defined in quantum mechanics is perfectly valid as far as it goes, it misses essential features of nature and has to be revisited and extended.

High Mobility N-Type Field Effect Transistors Enabled By Wse2/Pdse2 Heterojunctions, Arthur Bowman Iii

Wayne State University Dissertations

Two-dimensional (2D) semiconductors such as transition metal dichalcogenides (TMDs) have emerged as a promising candidate for post-silicon electronics. Few-layer tungsten diselenide (WSe2), a well-studied TMD, has sown high hole mobility and ON/OFF ratio in field effect transistor (FET) devices. But the n-type performance of WSe2 is still quite limited by the presence of a substantial Schottky Barrier. Palladium diselenide, (PdSe2) is a newly discovered TMD that is of interest because of its high electron mobility, and moderate ON/OFF ratios. However, despite its relatively small bandgap, the n-type performance of few-layer PdSe2 FETs has also been limited by a Schottky barrier, …

Photoemission Investigation Of Topological Quantum Materials, Klauss M. Dimitri

Honors Undergraduate Theses

Topological insulators (TIs) are a class of quantum materials, which behave as insulators in the bulk, yet possess gapless spin-polarized surface states, which are robust against nonmagnetic impurities. The unique properties of TIs make them attractive not only for studying various fundamental phenomena in condensed matter and particle physics, but also as promising candidates for applications ranging from spintronics to quantum computation. Within the topological insulator realm, a great deal of focus has been placed on discovering new quantum materials, however, ideal multi-modal quantum materials have yet to be found. Here we study alpha-PdBi2, KFe2Te2, and DySb compounds including others …

Dynamics For Discretized Gravity In The Causal Set Approach, Benjamin Pilgrim

Electronic Theses and Dissertations

Causal set theory is an approach to quantum gravity which replaces the continuous spacetime manifold with a discrete set of points and a partial order. In this work, I will focus on causal sets embeddable in two-dimensional manifolds, and define an action based on chains which in the continuum limit replicates the Einstein-Hilbert action; furthermore, I will propose a variational principle based on this action and numerically show it can distinguish nonflat manifoldlike causal sets from the most common type of nonmanifoldlike causal sets. I will then supplement this action with a boundary term similar to the Gibbons-Hawking-York boundary term …

Semiclassical Backreaction On Asymptotically Anti–De Sitter Black Holes, Peter Taylor, Cormac Breen

Articles

We consider a quantum scalar field on the classical background of an asymptotically anti–de Sitter black hole and the backreaction the field’s stress-energy tensor induces on the black hole geometry. The backreaction is computed by solving the reduced-order semiclassical Einstein field equations sourced by simple analytical approximations for the renormalized expectation value of the scalar field stress-energy tensor. When the field is massless and conformally coupled, we adopt Page’s approximation to the renormalized stress-energy tensor, while for massive fields we adopt a modified version of the DeWitt-Schwinger approximation. The latter approximation must be modified so that it possesses the correct …