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Quantum Information in Rydberg-Dressed Atoms
No full textIn any physical platform, two ingredients are essential for quantum information processing: single-qubit control, and entangling interactions between qubits. Neutral atoms can be individually controlled with high fidelity and are resilient to environmental noise, making them attractive candidates for implementing quantum information protocols. However, achieving strong interactions remains a major obstacle. One way to increase the interaction strength between neutral atoms is to excite them into high-lying Rydberg states, which exhibit large electric dipole moments (and by extension, strong electric dipole-dipole interactions). By slowly ramping up the Rydberg level coupling in a system, one can "dress'' the atomic ground states with some Rydberg character; this maps the Rydberg dipole interaction to an effective interaction between ground states. Such Rydberg-dressed interaction is the focus of this dissertation.
After describing the physics of the Rydberg-dressed interaction, we propose three protocols that demonstrate its versatility and provide a framework for considering some of the details of realistic implementation. In all three cases, Rydberg dressing --- along with some form of single-atom control --- is used to generate highly entangled states of interest. Our first proposal relates to the adiabatic model of quantum computing, in which solutions to problems are encoded in the ground states of carefully engineered Hamiltonians. The Rydberg-dressed interaction can provide nonlinear Hamiltonian terms, allowing us to encode NP-hard and other interesting problems. We model this protocol in the presence of decoherence, and find that computational fidelities of ~0.98 for four atoms should be possible with currently realistic experimental parameters.
Our second proposal is also related to quantum computing, this time in the circuit model. The Rydberg-dressed interaction can be used to generate a controlled-NOT logic gate which, when interwoven with single-qubit gates, can perform universal quantum computation. Experimentally, noise due to atomic thermal motion has been a primary limitation on the fidelities of these gates. We show that a Doppler-free setup, with counterpropagating lasers, effectively suppresses this type of noise, allowing simulated fidelities of up to ~0.998 per gate. Such strong suppression is only possible because the Doppler-free configuration can harness the natural robustness of adiabatic dressing; other gate schemes using, e.g., resonant pulses, do not exhibit the same degree of improvement.
Finally, we consider exploiting the many-body character of the Rydberg-dressed interaction to generate collective entanglement in mesoscopic ensembles of neutral atoms. An atomic ensemble uniformly illuminated by a single Rydberg-exciting laser is isomorphic to the well-known Jaynes-Cummings model. In addition to adapting generic Jaynes-Cummings entanglement protocols developed in other platforms, one can apply microwaves to drive entanglement in a way that is unique to the atomic platform. We prove that by allowing the microwave phase to vary in time, one can generate arbitrary symmetric states of the ensemble. While this method compares favorably with other entanglement protocols in many ways, the required frequency of phase switching presents a fundamental limitation on its effectiveness. To mitigate this, we propose a variant scheme in which parameters are chosen to only allow excitations within the system's dressed-ground subspace; this effectively cuts phase switching demands in half. All three protocols serve to illustrate the power of the Rydberg-dressed interaction and suggest directions for future study.Sandia National LaboratoriesPhysicsDoctoralUniversity of New Mexico. Dept. of Physics & AstronomyDeutsch, IvanMiyake, AkimasaBecerra-Chavez, Elohim FranciscoBiedermann, Gran
Lifts of Frobenius on Arithmetic Jet Spaces of Schemes
No full textLifts of Frobenius on formal schemes X over the p-adic completion of the maximal unramified extension of the p-adic integers may be viewed as arithmetic analogues of vector fields on manifolds. In particular, vector fields on the tangent bundle of a manifold, appearing for instance in Hamiltonian mechanics, have as arithmetic analogues lifts of Frobenius on arithmetic jet spaces J^1(X) of schemes.
In this thesis, we first consider the projective space P^m and prove that lifts of Frobenius do not exist on its arithmetic jet spaces J^n(P^m_R) for n, m >= 1. Exhibiting a contrast in the case n=m=1 between the arithmetic and geometric frameworks, we show on the other hand that the space of vector fields on the tangent bundle T(P^1_k) lifting vector fields on P^1_k, where k is an algebraically closed field, has dimension 6 over k. Nevertheless, "normalized" vector fields, which play a role in Hamiltonian mechanics, do not exist on T(P^1_k). We proceed to prove a stronger result for the case n=m=1, that there are no effective Cartier divisors on J^2(P^1) that are finite-to-one over J^1(P^1), and discover that an analogous result holds in geometry.
As a final result, we prove the nonexistence of lifts of Frobenius on the first jet space of any smooth quadric hypersurface in projective space.MathematicsDoctoralUniversity of New Mexico. Dept. of Mathematics and StatisticsBuium, AlexandruVassilev, JanetNakamaye, MichaelBorger, Jame
UAP 3290 from 2016.01.28 to CURRENT - MARKED UP VERSION
No full textProcess Owner: Vice President for Human Resource
Ultrafast Broadband Terahertz Spectroscopy
No full textThis dissertation centers on broadband terahertz spectroscopy and is arranged in four main sections. In the first section, we describe terahertz generation from a two-color laser air breakdown plasma. This is modeled with a plasma current that includes plasma density and dispersion in propagation. The terahertz spatial profile has a ring-like structure with a frequency dependent radius. Parameters for optimal terahertz generation are also presented. The next two sections discuss broadband terahertz detection techniques: optically biased coherent detection and electro-absorption in a semiconductor. The subject of the fourth section is terahertz imaging with electroabsorption.
Optically biased coherent detection is distinguished from air-breakdown coherent detection by replacing the electrical bias for an optical field. The importance of phase control in this technique is demonstrated. In addition, we found the terahertz-induced second harmonic to be spectrally delay-dependent. This is due to the phase matching condition and is discussed in detail.
Terahertz-induced electro-absorption is performed in GaAs/AlGaAs multiple double quantum wells and an AlGaAs bulk semiconductor. To the best of the author's knowledge, this is the first demonstration of large modulation induced by a single cycle terahertz pulse in such structures. The underlying mechanism is identified as the Franz-Keldysh effect that has been successfully modeled in both the temporal and spectral regimes.
Terahertz imaging of the plasma profile is accomplished with electro-absorption in these structures. The observed ring pattern is reproduced with the model described in the first section of this dissertation. Terahertz raster scan imaging of a large object is also presented.Optical Science and EngineeringDoctoralUniversity of New Mexico. Dept. of Physics & AstronomyShiek-Bahae, MansoorMalloy, KevinHayat, MajeedJeffrey, Cederber
A Guayaba's Heart
No full textA Guayaba's Heart is a poetry collection that is utilizes memory as a binding for the themes of language, family, and Central American landscapes, The poetry collection takes a close look at these themes through a generational lens and gives space to the unveiling of family secrets, the imaginary homeland, and interweaving binaries of language.Master of Fine ArtsDoctoralUniversity of New Mexico. Dept. of EnglishTapahonso, LuciBenz, SteveViscaíno-Alemán, MelinaQuesada, Rube
Experimental Verification of the Concept of the Relativistic Magnetron with Simple Mode Converter
No full textA compact A6 relativistic magnetron with a simple mode converter for axial TE_11-mode extraction was recently designed at the University of New Mexico. With the standard A6 magnetron operating in the -mode it is possible to implement a simple mode converter to radiate a TE_11-mode axially through a cylindrical waveguide whose radius is the same as the anode cavity radius. The proposed mode converter implements an anode end cap that electrically opens diametrically opposite cavities that produce an electric field polarization corresponding to that of the of the TE_11-mode in a cylindrical waveguide. The TE_11-mode has a Gaussian-like profile with maximum electric field on axis, and is desirable for applications.
In this work an extensive parametric sweep was conducted using the three dimensional particle-in-cell (PIC) code MAGIC to optimize the mode converter design. The cathode used is the transparent cathode with a radius chosen to favor -mode operation of the magnetron.
The trends observed in simulation have been verified experimentally. Simulations showed magnetron operation in π-mode at 2.33 GHz, and the output waveguide mode for these operating conditions was verified to be the TE_11-mode. In experiments performed at approximately the same operating magnetic field a single frequency RF signal at 2.33 GHz was detected. A neon grid used for mode detection confirmed a maximum in the center, which is indicative of the TE_11-mode. The radiated power is in the order of ~100’s of MW.The research presented in this thesis was supported by ONR Grants N00014-13-1-0565, N00014-15-1-2700, and N00014-16-1-2000, Dr. Joong Kim, Program Officer.
Electrical EngineeringMastersUniversity of New Mexico. Dept. of Electrical and Computer EngineeringSchamiloglu, EdlPrasad, SaritaGilmore, Mar
Teaching Through Testimonio: Language Arts Curriculum Made Relevant to Mexican/Mexican-American Adolescents
No full textThe goal of this self-study is to understand and make visible the process by which one first-year White, middle class, and female teacher in a largely Mexican/Mexican-American community creates curriculum that centers voices from marginalized backgrounds in efforts to engage students’ lived realities and challenge the traditional curriculum of a 9th grade English Language Arts classroom. This curriculum was developed while enrolled in a teacher education course titled, EDUC 593: Teaching Reading and Writing in the Content Area: Engaging Literacy through Latin American Testimonios of Struggle and Survival. This course serves to the inform choices made in curriculum as well as guide this self-study in order to shed light on how I came to understand literacy and education, especially for marginalized adolescents of Mexican/Mexican-American descent. This paper describes how Testimonio as pedagogy advises Culturally Relevant Teaching, and argues for an expanded definition of literacy. Findings from curriculum data are paralleled with data from the teacher education course, the analysis of these two sources reveals the realities of teaching through Testimonio in both curriculum and pedagogy.M.A., Secondary EducationMastersUniversity of New Mexico. Dept. of Teacher EducationSosa-Provencio, MiaZancanella, Donal
Dynamics of Turbulence and Flows in a Helicon Plasma Under Electrode Biasing
No full textExperimental studies investigating turbulence, and sheared flow were carried out using the linear Helicon-Cathode (HelCat) device. Without any outside influence, such as biasing or momentum input, fluctuations were observed. The dynamics of these fluctuations was found to vary with magnetic field, varying in both frequency and mode number. At low-field, the fluctuations were observed to be coherent, while at high fields, they were found to have turbulent characteristics. The first goal of this work was to identify the drive of the fluctuations.
This was completed by taking detailed radial measurements at two axial positions at five magnetic fields: 19.2 mT, 44 mT, 61.6 mT, 79.2 mT, and 129.5 mT. Experimental results were compared to linear theories, and analysis was completed to identify the mode at each magnetic field. In addition, the results were verified using Linear Stability Solver code (LSS), which utilized the electrostatic Braginskii equations. Both results indicated that the mode was a hybrid mode between the Kelvin-Helmholtz instability and the drift-wave instability. The generation of this hybrid mode is believed to be caused by changes in the axial parameters, particularly the density and potential gradients.
In order to affect these fluctuations, and explore the effect of sheared flow, a gridded electrode was placed 0.7 m downstream from the source. This grid was nearly transparent, and had a diameter of 17 cm, which covered the majority of the plasma radius, which is estimated to be 20-30 cm in diameter. The electrode was biased with respect to the chamber wall, thereby generating a radial electric field. This in turn is modifies the azimuthal flow, which is believed to be EB dominated.
Grid bias was found to have various effects depending on the bias and magnetic field strength. It was found that the application of negative grid bias ( V) once coherent fluctuations were driven into a broad-band turbulent mode. The electric field in was observed to become strongly negative (inward pointing) with the negative bias. At lower magnetic fields, this resulted in a steeper electric field gradient, which corresponds to a steeper shear flow. However, at high magnetic fields, the shear was not as steep, indicating a change in the drive-physics.
With an increase towards positive bias, the fluctuation magnitude of density and potential was exhibited to decrease. However, it was found that the density-potential cross-phase, and fluctuating radial flux, increased initially. This initial increase changed as the turbulent fluctuations were observed to transition to a coherent mode, where it was observed that the flux more closely followed changes in the density and potential fluctuation magnitude.
With a positive bias, the fluctuation levels could generally be reduced, and at certain radii, suppressed. Again, changes were observed to occur in the radial electric field, with the field now exhibiting both positive (outward pointing) and negative (inward pointing) components. At low magnetic fields, the shear decreased at inner radii, but increased at the edge, which was consistent with the drive regions of the Kelvin-Helmholtz mode whose drive was stronger at inner radii, and the drift-mode whose drive dominated at the edge. However, with higher magnetic field, positive bias lead to stronger shear overall.
In the higher magnetic field case, B=129.5 mT, a positive bias up to V was applied, and appeared to have minimal effect. However, flux data and fast imaging revealed that the positive bias lead to a shift in the turbulence. With negative bias, the flux was strongly outward, but the positive bias lead to a fully inward transport of flux. This was captured and verified with fast imaging. The exact nature and effect of this inward flux is still not well understood.
The last part of this work focused on a purely non-linear instability known as the potential relaxation instability, or PRI. This instability was first generated by accident, and was found to exist only at low magnetic fields. It occurred when a high positive bias was applied; this resulted in the rise of large scale fluctuations, with density fluctuations magnitudes . Plasma from unbiased boundaries was found to travel axially towards the biased electrode, and to be accelerated to supersonic values , where is the nominal ion sound speed.National Science FoundationElectrical EngineeringDoctoralUniversity of New Mexico. Dept. of Electrical and Computer EngineeringGilmore, MarkFisher, DustinRicci, PaoloSchamiloglu, Ed
Spring 2016 Department of Family and Child Studies APR Self-Study Report
No full textAPR self-study report fulfills requirements of the Higher Learning Commission, UNM's accrediting bod
23 July 1944 RIO ARRIBA County Specimen Collection Data
No full textSpecimen collected 23 July 1944. Original Locality: Rio Grande, drain (east) Trampus Lake. Locality: Rio Grande, drain (east) Trampus Lake.Catalog number: MSB1923; Taxa: Oncorhynchus clarkii; Common name: cutthroat trout; Count of specimens: 1; Standard length