38 research outputs found
Observation of Quantum Effects in sub Kelvin Cold Reactions
There has been a long-standing quest to observe chemical reactions at low
temperatures where reaction rates and pathways are governed by quantum
mechanical effects. So far this field of Quantum Chemistry has been dominated
by theory. The difficulty has been to realize in the laboratory low enough
collisional velocities between neutral reactants, so that the quantum wave
nature could be observed. We report here the first realization of merged
neutral supersonic beams, and the observation of clear quantum effects in the
resulting reactions. We observe orbiting resonances in the Penning ionization
reaction of argon and molecular hydrogen with metastable helium leading to a
sharp increase in the absolute reaction rate in the energy range corresponding
to a few degrees kelvin down to 10 mK. Our method is widely applicable to many
canonical chemical reactions, and will enable a breakthrough in the
experimental study of Quantum Chemistry
Systematic and statistical uncertainty evaluation of the HfF electron electric dipole moment experiment
We have completed a new precision measurement of the electron's electric
dipole moment using trapped HfF in rotating bias fields. We report on the
accuracy evaluation of this measurement, describing the mechanisms behind our
systematic shifts. Our systematic uncertainty is reduced by a factor of 30
compared to the first generation of this measurement. Our combined statistical
and systematic accuracy is improved by a factor of 2 relative to any previous
measurement
A new bound on the electron's electric dipole moment
The Standard Model cannot explain the dominance of matter over anti-matter in
our universe. This imbalance indicates undiscovered physics that violates
combined CP symmetry. Many extensions to the Standard Model seek to explain the
imbalance by predicting the existence of new particles. Vacuum fluctuations of
the fields associated with these new particles can interact with known
particles and make small modifications to their properties; for example,
particles which violate CP symmetry will induce an electric dipole moment of
the electron (eEDM). The size of the induced eEDM is dependent on the masses of
the new particles and their coupling to the Standard Model. To date, no eEDM
has been detected, but increasingly precise measurements probe new physics with
higher masses and weaker couplings. Here we present the most precise
measurement yet of the eEDM using electrons confined inside molecular ions,
subjected to a huge intra-molecular electric field, and evolving coherently for
up to 3 s. Our result is consistent with zero and improves on the previous best
upper bound by a factor . Our sensitivity to eV shifts in
molecular ions provides constraints on broad classes of new physics above
eV, well beyond the direct reach of the LHC or any other near- or
medium-term particle collider.Comment: Update to figure 2 which displays better in some pdf viewer
Experimental Constraint on Axionlike Particles over Seven Orders of Magnitude in Mass
We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the HfF+ EDM oscillates in time due to interactions with candidate dark matter axionlike particles (ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range 10-22-10-15 eV. This is the first laboratory constraint on the ALP-gluon coupling in the 10-17-10-15 eV range, and the first laboratory constraint to properly account for the stochastic nature of the ALP field
Recommended from our members
Laser beam shaping techniques
Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques
Grain Yield and Nutrient Uptake of Rice as Influenced by the Nano Forms of Nitrogen and Zinc
An experiment was conducted at college farm, College of Agriculture, Rajendranagar, Hyderabad, Telangana, in Sandy loam soils during rabi, 2020 to study the effect of nano nitrogen and nano zinc on the yield and nutrient uptake of rice (Oryza sativa. L). The experiment was carried out in randomised block design with 10 treatments and 3 replications. Results revealed that application of 50% conventional nitrogen fertilizer + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T10) significantly increased the grain yield (6810 kg ha-1) and uptake of nitrogen (147.7 kg ha-1), phosphorous (30.0 kg ha-1), potassium (137.9 kg ha-1) and zinc (367 kg ha-1) which were on par with (T9) application of 50% conventional nitrogen fertilizer + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage