The best upper limit for the electron electric dipole moment was recently set by the ACME collaboration. This experiment measures an electron spin-precession in a cold beam of ThO molecules in their metastable
The sensitivity of urban canopy air temperature (
- NSF-PAR ID:
- 10441068
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Environmental Research Letters
- Volume:
- 18
- Issue:
- 9
- ISSN:
- 1748-9326
- Page Range / eLocation ID:
- Article No. 094005
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract state. Improvement in the statistical and systematic uncertainties is possible with more efficient use of molecules from the source and better magnetometry in the experiment, respectively. Here, we report measurements of several relevant properties of the long-lived state of ThO, and show that this state is a very useful resource for both these purposes. TheQ state lifetime is long enough that its decay during the time of flight in the ACME beam experiment is negligible. The large electric dipole moment measured for theQ state, giving rise to a large linear Stark shift, is ideal for an electrostatic lens that increases the fraction of molecules detected downstream. The measured magnetic moment of theQ state is also large enough to be used as a sensitive co-magnetometer in ACME. Finally, we show that theQ state has a large transition dipole moment to the state, which allows for efficient population transfer between the ground state and theQ state via Stimulated Raman Adiabatic Passage (STIRAP). We demonstrate 90 % STIRAP transfer efficiency. In the course of these measurements, we also determine the magnetic moment ofC state, the transition dipole moment, and branching ratios of decays from theC state. -
Abstract M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which share similar
T eff∼ 2300–2800 K. We present atmospheric analyses for the M7.5 companion HIP 55507 B and its K6V primary star with Keck/KPIC high-resolution (R ∼ 35,000)K -band spectroscopy. First, by including KPIC relative radial velocities between the primary and secondary in the orbit fit, we improve the dynamical mass precision by 60% and find , putting HIP 55507 B above the stellar–substellar boundary. We also find that HIP 55507 B orbits its K6V primary star with au ande = 0.40 ± 0.04. From atmospheric retrievals of HIP 55507 B, we measure [C/H] = 0.24 ± 0.13, [O/H] = 0.15 ± 0.13, and C/O = 0.67 ± 0.04. Moreover, we strongly detect13CO (7.8σ significance) and tentatively detect (3.7σ significance) in the companion’s atmosphere and measure and after accounting for systematic errors. From a simplified retrieval analysis of HIP 55507 A, we measure and for the primary star. These results demonstrate that HIP 55507 A and B have consistent12C/13C and16O/18O to the <1σ level, as expected for a chemically homogeneous binary system. Given the similar flux ratios and separations between HIP 55507 AB and systems with young substellar companions, our results open the door to systematically measuring13CO and abundances in the atmospheres of substellar or even planetary-mass companions with similar spectral types. -
Abstract We consider a process of noncolliding
q -exchangeable random walks on making steps 0 (‘straight’) and −1 (‘down’). A single random walk is calledq -exchangeable if under an elementary transposition of the neighboring steps the probability of the trajectory is multiplied by a parameter . Our process ofm noncollidingq -exchangeable random walks is obtained from the independentq -exchangeable walks via the Doob’sh -transform for a nonnegative eigenfunctionh (expressed via theq -Vandermonde product) with the eigenvalue less than 1. The system ofm walks evolves in the presence of an absorbing wall at 0. The repulsion mechanism is theq -analogue of the Coulomb repulsion of random matrix eigenvalues undergoing Dyson Brownian motion. However, in our model, the particles are confined to the positive half-line and do not spread as Brownian motions or simple random walks. We show that the trajectory of the noncollidingq -exchangeable walks started from an arbitrary initial configuration forms a determinantal point process, and express its kernel in a double contour integral form. This kernel is obtained as a limit from the correlation kernel ofq -distributed random lozenge tilings of sawtooth polygons. In the limit as , withγ > 0 fixed, and under a suitable scaling of the initial data, we obtain a limit shape of our noncolliding walks and also show that their local statistics are governed by the incomplete beta kernel. The latter is a distinguished translation invariant ergodic extension of the two-dimensional discrete sine kernel. -
Abstract We present a detection of 21 cm emission from large-scale structure (LSS) between redshift 0.78 and 1.43 made with the Canadian Hydrogen Intensity Mapping Experiment. Radio observations acquired over 102 nights are used to construct maps that are foreground filtered and stacked on the angular and spectral locations of luminous red galaxies (LRGs), emission-line galaxies (ELGs), and quasars (QSOs) from the eBOSS clustering catalogs. We find decisive evidence for a detection when stacking on all three tracers of LSS, with the logarithm of the Bayes factor equal to 18.9 (LRG), 10.8 (ELG), and 56.3 (QSO). An alternative frequentist interpretation, based on the likelihood ratio test, yields a detection significance of 7.1
σ (LRG), 5.7σ (ELG), and 11.1σ (QSO). These are the first 21 cm intensity mapping measurements made with an interferometer. We constrain the effective clustering amplitude of neutral hydrogen (Hi ), defined as , where ΩHi is the cosmic abundance of Hi ,b Hi is the linear bias of Hi , and 〈f μ 2〉 = 0.552 encodes the effect of redshift-space distortions at linear order. We find for LRGs (z = 0.84), for ELGs (z = 0.96), and for QSOs (z = 1.20), with constraints limited by modeling uncertainties at nonlinear scales. We are also sensitive to bias in the spectroscopic redshifts of each tracer, and we find a nonzero bias Δv = − 66 ± 20 km s−1for the QSOs. We split the QSO catalog into three redshift bins and have a decisive detection in each, with the upper bin atz = 1.30 producing the highest-redshift 21 cm intensity mapping measurement thus far. -
Abstract The genericity of Arnold diffusion in the analytic category is an open problem. In this paper, we study this problem in the following
a priori unstable Hamiltonian system with a time-periodic perturbation where , withn ,d ⩾ 1,V i are Morse potentials, andɛ is a small non-zero parameter. The unperturbed Hamiltonian is not necessarily convex, and the induced inner dynamics does not need to satisfy a twist condition. Using geometric methods we prove that Arnold diffusion occurs for generic analytic perturbationsH 1. Indeed, the set of admissibleH 1isC ω dense andC 3open (a fortiori ,C ω open). Our perturbative technique for the genericity is valid in theC k topology for allk ∈ [3, ∞) ∪ {∞,ω }.