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The gravitational acceleration of antimatter,ḡ, has yet to be directly measured; an unexpected outcome of its measurement could change our understanding of gravity, the universe, and the possibility of a fifth force. Three avenues are apparent for such a measurement: antihydrogen, positronium, and muonium, the last requiring a precision atom interferometer and novel muonium beam under development. The interferometer and its few-picometer alignment and calibration systems appear feasible. With 100 nm grating pitch, measurements ofḡ to 10%, 1%, or better can be envisioned. These could constitute the first gravitational measurements of leptonic matter, of 2 nd -generation matter, and possibly, of antimatter.And we note that arguments based on absolute gravitational potentials have been critiqued by Nieto and Goldman [2].Atoms 2018, xx, x 2 of 14 on quite general grounds [2]. 2 Such a measurement can be viewed as a test of general relativity or as a search for a fifth force and is of interest from both perspectives.Although the equivalence principle experiments indicate that nuclear binding energy gravitates in the same way as ordinary mass, absent validated models of gravity at a subnuclear scale, it is unclear how the gravitational interactions of virtual matter should be treated. Use of a pure-leptonic atom, such as positronium or muonium, evades these complexities. Moreover, no measurement has yet been made of the gravitational force on second-or third-generation matter or antimatter (although, with some assumptions, stringent limits can be obtained from neutral-meson oscillations, especially for K 0 -K 0 [14]). Since direct gravitational measurements on other higher-generation particles, such as hyperons, τ leptons, and c or b hadrons, appear impractical due to their short lifetimes, muonium may be the only access we have. Recent work [15][16][17] examining a possible standard-model extension emphasizes the importance of second-generation gravitational measurements. Current interest in "fifth force" models [18,19] (stimulated by evident anomalies in the leptonic decays of B mesons) also supports more detailed investigations of muonium.General relativity (GR) is generally taken to predict identical behaviors of antimatter and matter in a gravitational field. With the observation of gravitational waves [20], most of the predictions of GR are now experimentally confirmed. Nevertheless, GR is fundamentally incompatible with quantum mechanics, and the search for a quantum theory of gravity continues [21]. To date, the experimental evidence on which to base such a theory comes from observations of matter-matter and matter-light interactions. In a quantum field theory, matter-matter and matter-antimatter forces can differ -for example, suppressed scalar and vector terms might cancel in matter-matter interactions, but add in matter-antimatter ones [2], leading to small equivalence principle violations. Matter-antimatter measurements could thus play a key role.While most physicists expect that the equivalence principle a...

Background: Since the start of the COVID-19 pandemic outpatient medicine has drastically been altered how it is delivered. This time period likely represents the largest volume of telehealth visits in the United States health care history. Telehealth presents unique challenges within each subspecialty, and pediatric otolaryngology is no different. This retrospective review was designed to evaluate our division of pediatric otolaryngology’s experience with telehealth during the COVID19 pandemic. Methods: This study was approved by the Institutional Review Board at Vanderbilt University Medical Center. All telehealth and face-to-face visits for the month of April 2020 completed by the Pediatric Otolaryngology Division were reviewed. A survey, utilizing both open-ended questions and Likert scaled questions was distributed to the 16 pediatric otolaryngology providers in our group to reflect their experience with telehealth during the 1-month study period. Results: In April, 2020 our outpatient clinic performed a total of 877 clinic visits compared to 2260 clinic visits in April 2019. A total of 769 (88%) were telehealth visits. Telemedicine with video comprised 523 (68%) and telephone only comprised 246 (32%). There were 0 telehealth visits in April 2019. Interpretive services were required in 9.3% (N = 211) clinic visits in April 2019 and 7.5% (N = 66) of clinic visits in April 2020. The survey demonstrated a significant difference ( P < .00002) in provider’s anticipated telehealth experience (mean 3.94, 95% CI [3.0632, 4.8118] compared to their actual experience after the study period (mean 7.5, 95% CI [7.113, 7.887]. Conclusions: Despite low initial expectations for telehealth, the majority of our providers felt after 1 month of use that telehealth would continue to be a valuable platform post-pandemic clinical practice. Limited physical exam, particularly otoscopy, nasal endoscopy, and nasolaryngoscopy present challenges. However, with adequate information and preparation for the parents and for the physician some of the obstacles can be overcome.

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We describe a Galilean test of the weak equivalence principle, to be conducted during the free fall portion of a sounding rocket flight. The test of a single pair of substances is aimed at a measurement uncertainty of () < 10 -16 after averaging the results of eight separate drops. The weak equivalence principle measurement is made with a set of four laser gauges that are expected to achieve 0.1 pm Hz -1/2 . The discovery of a violation (η ≠ 0) would have profound implications for physics, astrophysics, and cosmology.

We describe SR-POEM, a Galilean test of the weak equivalence principle, which is to be conducted during the free fall portion of a sounding rocket flight. This test of a single pair of substances is aimed at a measurement uncertainty of () < 10 -16 after averaging the results of eight separate drops, each of 40 s duration. The weak equivalence principle measurement is made with a set of four laser gauges that are expected to achieve 0.1 pm Hz -1/2 . We address the two sources of systematic error that are currently of greatest concern, magnetic force and electrostatic (patch effect) force on the test mass assemblies. The discovery of a violation (η ≠ 0) would have profound implications for physics, astrophysics and cosmology.

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We describe SR-POEM, a Galilean test of the weak equivalence principle that is to be conducted during the free fall portion of the flight of a sounding rocket payload. This test of a single pair of substances will have a measurement uncertainty of () < 2 ä 10 -17 after averaging the results of eight separate drops, each of 120 s duration. The entire payload is inverted between successive drops to cancel potential sources of systematic error. The weak equivalence principle measurement is made with a set of four of the SAO laser gauges, which have achieved an Allan deviation of 0.04 pm for an averaging time of 30 s. We discuss aspects of the current design with an emphasis on those that bear on the accuracy of the determination of η. The discovery of a violation (η ≠ 0) would have profound implications for physics, astrophysics and cosmology.