Free radical and overtone spectroscopy

In the fall of 1987 during a photoacoustic study of hydrogen peroxide's fourth vibrational overtone band, the remarkably clear and well resolved spectrum was observed. Its periodicity and K subband structure suggested that the spectrum was not of hydrogen peroxide but of a smaller near-prolate symmetric top molecule. Furthermore, the time dependent behavior of the signal indicated that chemical changes were taking place within the photoacoustic apparatus

Short-term headline-core inflation dynamics

This article investigates empirically short-term dynamics between headline and core measures of consumer price index and personal consumption expenditure inflation over three sample periods: 1959:1-1979:1, 1979:2-2001:2, and 1985:1-2007:2. Headline and core inflation measures are co-integrated, suggesting long-run co-movement. However, the ways these two variables adjust to each other in the short run and generate co-movement have changed across these sample periods. In the pre-1979 sample period, when a positive gap opens up with headline inflation rising above core inflation, the gap is eliminated mainly as a result of headline inflation not reverting and core inflation moving toward headline inflation. These dynamics suggest headline inflation would be better than core inflation in assessing the permanent component of inflation. In post-1979 sample periods, however, the positive gap is eliminated as a result of headline inflation reverting more strongly toward core inflation than core inflation moving toward headline inflation, suggesting core inflation would be better than headline inflation in assessing the permanent component of inflation. This change in headline-core inflation dynamics may be due to the Federal Reserve having convinced the public it would no longer accommodate shocks to food and energy prices.Inflation (Finance) ; Monetary policy

The L-/C-band feed design for the DSS 14 70-meter antenna (Phobos mission)

A dual-frequency (1.668 and 5.01 GHz) feed was designed for the Deep Space Station (DSS) 14 70-m antenna to support the Soviet Phobos Mission. This antenna system was capable of supporting telemetry, two-way Doppler, and very long baseline interferometry (VLBI). VLBI and two-way Doppler information on the Phobos spacecraft was acquired with this antenna in 1989

Fast Single-Charge Sensing with an rf Quantum Point Contact

We report high-bandwidth charge sensing measurements using a GaAs quantum point contact embedded in a radio frequency impedance matching circuit (rf-QPC). With the rf-QPC biased near pinch-off where it is most sensitive to charge, we demonstrate a conductance sensitivity of 5x10^(-6) e^(2)/h Hz^(-1/2) with a bandwidth of 8 MHz. Single-shot readout of a proximal few-electron double quantum dot is investigated in a mode where the rf-QPC back-action is rapidly switched.Comment: related papers available at http://marcuslab.harvard.ed

Researching protest on Facebook: developing an ethical stance for the study of Northern Irish flag protest pages

This paper adds to the emergent literature on Internet research ethics by exploring the ethical implications of researching the use of Facebook to organize the union flag protests in Northern Ireland in January 2013. These protests were viewed as a ‘lightning rod’ for loyalist dissatisfaction with the peace process, as well as a manifestation of their increasing alienation from their unionist political representatives. The covert observation of the Loyalist Peaceful Protest Updater (LPPU) page in January 2013 found some evidence to support the suggestion that social media had become a ‘sectarian battleground’ during the flag protests. This created an ethical dilemma in terms of what level of anonymity should be afforded to those who posted such content on the page. While there was no requirement to ‘please’ unaware participants, the researcher was wary of inadvertently contributing to the online shaming of loyalists by groups such as Loyalists Against Democracy. Therefore, it was decided to only use direct quotes from public figures, such as the leaders of the flag protest movement, who would presumably have no expectation that their comments would remain private. The narratives of the ‘rank and file’ protesters were conveyed through the use of direct quotes that could not be traced back to their authors and the paraphrasing of their comments. In light of the limitations of alternative strategies such as fabrication and word clouds, this was the most appropriate way to illustrate the themes from the LPPU without distorting the voices of these users

SECOR observations in the Pacific

Geometric adjustment technique for Pacific SECOR observations based on least squares metho

Rapid Single-Shot Measurement of a Singlet-Triplet Qubit

We report repeated single-shot measurements of the two-electron spin state in a GaAs double quantum dot. The readout scheme allows measurement with fidelity above 90% with a 7 microsecond cycle time. Hyperfine-induced precession between singlet and triplet states of the two-electron system are directly observed, as nuclear Overhauser fields are quasi-static on the time scale of the measurement cycle. Repeated measurements on millisecond to second time scales reveal evolution of the nuclear environment.Comment: supplemental material at http://marcuslab.harvard.edu/papers/single_shot_sup.pd

Transmission Lines and Meta-Materials based on Quantum Hall Plasmonics

The characteristic impedance of a microwave transmission line is typically constrained to a value $Z_0$ = 50 $\Omega$, in-part because of the low impedance of free space and the limited range of permittivity and permeability realizable with conventional materials. Here we suggest the possibility of constructing high-impedance transmission lines by exploiting the plasmonic response of edge states associated with the quantum Hall effect in gated devices. We analyze various implementations of quantum Hall transmission lines based on distributed networks and lumped-element circuits, including a detailed account of parasitic capacitance and Coulomb drag effects, which can modify device performance. We additionally conceive of a meta-material structure comprising arrays of quantum Hall droplets and analyze its unusual properties. The realization of such structures holds promise for efficiently wiring-up quantum circuits on chip, as well as engineering strong coupling between semiconductor qubits and microwave photons

X/X/Ka-band prime focus feed antenna for the Mars Observer beacon spacecraft

The results of an X/X/Ka-band feed design concept demonstration are presented. The purpose is to show the feasibility of adding a Ka-band beacon to the Mars Observer spacecraft. Scale model radiation patterns were made and analyzed