Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"atomic clock"”.
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Frequency stability in a compact, deployable optical atomic clock
… several decades have enabled a new generation of atomic clocks based on optical transitions as opposed to microwave transitions While optical atomic clocks in the laboratory outperform microwave standards by orders of magnitude, their complexity, size, weight, and power have so far precluded their …
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Cavity-enabled spin squeezing for a quantum-enhanced atomic clock
For the past decade, the stability of microwave atomic clocks has stood at the standard quantum limit, set by the projection noise inherent in measurements on ensembles of uncorrelated particles. Here, I demonstrate an atomic clock that surpasses this limit by operating with atoms in a particular …
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Atomic Clock Augmentation For Receivers Using the Global Positioning System
… it is standard procedure to treat the receiver clock bias from GPS time as an unknown. This requires four range measurements to the satellites in order to solve for three dimensional position and clock offset. If the receiver clock could be synchronized with GPS time, the extra range measurement …
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Towards spin squeezed ¹⁷¹Yb atomic clock beyond the standard quantum limit
State-of-the-art atomic clocks have fractional frequency instability of 6 x 10-17 at 1 s averaging time, and are aiming for even higher stability. One of the main factors limiting this stability is the standard quantum limit (SQL) of quantum projection noise, which can be overcome by spin …
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Trapping and Laser Cooling an Ensemble of Ytterbium-171 Atoms for use in an Atomic Clock
Optical lattice clocks require careful preparation of atomic ensembles in order to ensure homogeneous interactions with the clock laser. We demonstrate loading and laser cooling of an ensemble of ytterbium-171 atoms in a 2D optical dipole trap created by an optical cavity. Our loading method …
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Micro-fabricated diffractive optics for quantum sensors and atomic clocks
… and experimental realisationof a cold-atom, atomic clock. Diffractive optics are used to address the size constraints of the typical laser cooling apparatus to facilitate a portable device. The design and measurement of a wide range of grating parameters, including period, duty cycle, etch …
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Predicting the future of atomic clocks using the Theory of Evolution
… systems will evolve over time. A cesium atomic clock is the most accurate realization of a reference unit that mankind has yet achieved. The commercial cesium atomic clock is very mature and the demand for this type of clocks expected to be flat. A size reduction is possible due to new …
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On the Variability of the Fine Structure Constant
… using astrophysical data and those obtained in atomic clock experiments. Suggestions are made on the nature of trapped particles and the trapping fields.
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A geometric approach to determination of satellite ephemeris over a limited area
… error, tropospheric refraction errors, and atomic clock errors have been considered, and the range observation adjustment program directed to solve for clock errors.
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A biography of the second
… second hand, today we are beholden to this new, atomic second far beyond matters of time. Our entire technological infrastructure, from airplanes to smartphones, televisions to stock markets, driving directions to space research, would crumble without the atomic second and the 21st century …
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Squeezing collective atomic spins with an optical resonator
… quantum limit of signal-to-noise ratio in atomic precision measurements. In both methods, the interaction between an ultracold atomic ensemble and an optical resonator serves to entangle the atoms and deform the uncertainty distribution of the collective hyperfine spin so that it is …
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Precision Metrology with Ytterbium Ions for New Physics Search
… searches is using quantum sensing tools based on Atomic, Molecular, and Optical physics. In particular, the modern optical atomic clocks demonstrate unprecedented accuracy and precision. Complementary to high-energy searches with particle colliders, the atomic clocks are used to place stringent …
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Investigation into a GPS time pulse radiator for testing time-stamp accuracy of a radio telescope
… Universal Time (UTC). The telescope has a local atomic clock ensemble and uses satellite based remote clock comparison techniques to compare the telescope time to UTC. The master clock timing edge is distributed to each telescope antenna via an optical fibre precise time transfer. Although the …
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Time and Frequency Transfer in a Coherent Multistatic Radar using a White Rabbit Network
… wireless operation, geospatial referencing, and atomic clock level time and frequency stability. However, such systems are liable to GNSS-denial, where the GNSS carrier is temporarily or permanently removed. A denial-resilient system should consider alternative TFT techniques, such as the White …
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Cavity quantum electrodynamics with ensembles of ytterbium-171
… tools of cavity quantum electrodynamics to an atomic optical lattice clock. We design and implement a unique experimental cavity structure, with a small radius of curvature mirror on one side and a large mirror on the other side. With this structure, we are able to probe ytterbium-171 atoms in …
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Manifestations of Dark Matter and Variations of the Fundamental Constants of Nature in Atoms and Astrophysical Phenomena
… particle masses), which may be sought for with atomic clock spectroscopy and laser interferometry measurements in the laboratory, as well as astrophysical big bang nucleosynthesis measurements. Other linear effects of dark matter include spin-precession effects and oscillating spin-gravity …
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Integrated Technologies and Control Techniques for Trapped Ion Array Architectures
… (SBS) laser for addressing an ion in an atomic clock protocol. In our experiment, the SBS laser is shown to have a linewidth commensurate with a bulk-cavity-stabilized laser and may offer a path towards generating highly-coherent light within an ion trap package. Subsequently, we explore …
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Optical quantum random number generation: applications of single-photon event timing
… of its bit-probability drift using atomic clock stability techniques. By employing the Allan deviation and implementing precision feedback, the additional frequency drift caused by environmental fluctuations is reduced such that the resulting bit stream can pass cryptographic random …
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ION TRAP SYSTEM TOWARDS 176LU+ 3D2 CLOCK TRANSITION
… has a unique property that it possesses multiple clock transitions. In combination with hyperfine averaging, two of these transitions (1S0 – 3D1 and 1S0 – 3D2) present both long lifetimes and low sensitivity to the electromagnetic environment. Fully characterizing both transitions allows for a …
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Construction of a Calcium Matter-Wave Interferometer
I describe the construction of a calcium matter-wave interferometer. The interferometer is based on a Ramsey-Borde scheme, and uses a thermal beam of atoms excited by an optical-frequency transition in calcium. In our experiment four pi/2 pulses of light are delivered to the atoms, which split and …
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