Utilization of Micro X-Ray Fluorescence Spectrometry (μXRF) in Analyzing Heavy Mineral Sorting Patterns in Biotic and Abiotic Depositional Environments

The field of evolutionary geobiology is focused largely on the presence of biosignatures in the geological record. Microbial mat communities have been shown to sort heavy element grains and produce patterns that differ from those seen in cross-laminated sandstones (Gerdes et al., 2000). The difference in spatial distribution patterns of heavy mineral grains may prove to be a viable biosignature. These patterns are studied using Micro X-ray Fluorescent Spectrometry to determine what significance or abundance, if any, exists between the patterns of distribution of heavy mineral grains contained within the two types of formations

BCS 100 Module 3: Northern Environments

The landscapes of the Circumpolar North have been shaped by the interplay of physical, chemical and biological processes operating over many millennia or many millions of years. Many of the physical features and processes found in the Circumpolar North are unique to this part of the earth. The flora and fauna of the northern regions are unique because the environments they inhabit are extreme and finely balanced. This module provides a brief introduction to the physical and biological features and processes of the Arctic and Subarctic regions and highlights the significant factors that influence those features and processes

Realizing spin squeezing with Rydberg interactions in a programmable optical clock

Neutral-atom arrays trapped in optical potentials are a powerful platform for studying quantum physics, combining precise single-particle control and detection with a range of tunable entangling interactions. For example, these capabilities have been leveraged for state-of-the-art frequency metrology as well as microscopic studies of entangled many-particle states. In this work, we combine these applications to realize spin squeezing - a widely studied operation for producing metrologically useful entanglement - in an optical atomic clock based on a programmable array of interacting optical qubits. In this first demonstration of Rydberg-mediated squeezing with a neutral-atom optical clock, we generate states that have almost 4 dB of metrological gain. Additionally, we perform a synchronous frequency comparison between independent squeezed states and observe a fractional frequency stability of $1.087(1)\times 10^{-15}$ at one-second averaging time, which is 1.94(1) dB below the standard quantum limit, and reaches a fractional precision at the $10^{-17}$ level during a half-hour measurement. We further leverage the programmable control afforded by optical tweezer arrays to apply local phase shifts in order to explore spin squeezing in measurements that operate beyond the relative coherence time with the optical local oscillator. The realization of this spin-squeezing protocol in a programmable atom-array clock opens the door to a wide range of quantum-information inspired techniques for optimal phase estimation and Heisenberg-limited optical atomic clocks.Comment: 13 pages, 4 figures; Supplementary Informatio

Growth direction determination of a single RuO2 nanowire by polarized Raman spectroscopy

The dependence of band intensities in the Raman spectrum of individual single-crystal ruthenium dioxide (RuO2) nanowires on the angle between the plane of polarization of the exciting (and collected) light and the long axis of the nanowire, is shown to be a simple, complementary technique to high resolution transmission electron microscopy (HRTEM) for determining nanowire growth direction. We show that excellent agreement exists between what is observed and what is predicted for the polarization angle dependence of the intensities of the nanowires' E-g (525 cm(-1)) and the B-2g (714 cm(-1)) Raman bands, only by assuming that the nanowires grow along the (001) crystallographic direction, as confirmed by HRTEM.open9

Hamiltonian and Linear-Space Structure for Damped Oscillators: I. General Theory

The phase space of $N$ damped linear oscillators is endowed with a bilinear map under which the evolution operator is symmetric. This analog of self-adjointness allows properties familiar from conservative systems to be recovered, e.g., eigenvectors are "orthogonal" under the bilinear map and obey sum rules, initial-value problems are readily solved and perturbation theory applies to the_complex_ eigenvalues. These concepts are conveniently represented in a biorthogonal basis.Comment: REVTeX4, 10pp., 1 PS figure. N.B.: `Alec' is my first name, `Maassen van den Brink' my family name. v2: extensive streamlinin