We examine the radiation emitted by high-energy positrons channeled into silicon crystal samples. The positrons are modeled as semiclassical vector currents coupled to an Unruh-DeWitt detector to ...incorporate any local change in the energy of the positron. In the subsequent accelerated QED analysis, we discover a Larmor formula and power spectrum that are both thermalized by the acceleration. Thus, these systems explicitly exhibit thermalization of the detector energy gap at the celebrated Fulling-Davies-Unruh (FDU) temperature. Our derived power spectrum, with a nonzero energy gap, is then shown to have an excellent statistical agreement with high-energy channeling experiments and also provides a method to directly measure the FDU temperature. We also investigate the Rindler horizon dynamics and confirm that the Bekenstein-Hawking area-entropy law is satisfied in these experiments. As such, we present the evidence for the first observation of acceleration-induced thermality in a nonanalog system.
Although research shows a strong positive association between perceived stress and loneliness, the genetic and environmental etiology underlying their association remains unknown. People with a ...genetic predisposition to perceived stress, for example, may be more prone to feeling lonely and vice versa. Conversely, unique factors in people’s lives may explain differences in perceived stress levels that, in turn, affect feelings of loneliness. We tested whether genetic factors, environmental factors, or both account for the association between perceived stress and loneliness. Participants were 3,066 individual twins (
n
Female
= 2,154, 70.3%) from the Washington State Twin Registry who completed a survey during April–May, 2020. Structural equation modeling was used to analyze the item-level perceived stress and loneliness measures. The correlation between latent perceived stress and latent loneliness was .68. Genetic and nonshared environmental variance components underlying perceived stress accounted for 3.71% and 23.26% of the total variance in loneliness, respectively. The genetic correlation between loneliness and perceived stress was .45 and did not differ significantly between men and women. The nonshared environmental correlation was .54 and also did not differ between men and women. Findings suggest that holding constant the strong genetic association between perceived stress and loneliness, unique life experiences underlying people’s perceived stress account for individual differences in loneliness.
In this manuscript we examine an accelerated charged particle moving through an optical medium, and explore the emission of accelerated-Cherenkov radiation. The particle's reaction to acceleration ...creates a low-frequency spectral cutoff in the Cherenkov emission that has a sharp resonance at the superluminal threshold. Moreover, the effect of recoil on the radiation is incorporated kinematically through the use of an Unruh-DeWitt detector by setting an energy gap, i.e. the change in electron energy, to the recoil energy of the emitted photon. The simultaneous presence of recoil and acceleration conspire to produce a localized resonance peak in the emission. These theoretical considerations could be used to construct high precision tests of radiation reaction using Cherenkov emission under acceleration.
Free‐Electron Qubits Reinhardt, Ori; Mechel, Chen; Lynch, Morgan ...
Annalen der Physik,
February 2021, Letnik:
533, Številka:
2
Journal Article
Recenzirano
Free‐electron interactions with laser‐driven nearfields can quantize the electrons’ energy spectrum and provide control over this quantized degree of freedom. The study proposes to use such ...interactions to promote free electrons as carriers of quantum information and show how to create a qubit on a free electron, which holds promise for applications in electron microscopy and spectroscopy. A method to implement the qubit's noncommutative spin algebra, and to control and measure the qubit state with a universal set of 1‐qubit gates is shown. These gates are within the current capabilities of ultrafast transmission electron microscopes. Laser‐driven free‐electron qubits promise configurability by the laser intensity, frequency, and polarizability, simultaneously with high‐resolution temporal control on femtosecond timescales.
This study shows a method to implement a qubit on a single free electron using the electron's interactions with laser‐driven nearfields that quantize the electron's energy spectrum. A method to implement the qubit's noncommutative spin algebra, then control and measure the qubit state with a universal set of 1‐qubit gates is shown. The method is within the current capabilities of ultrafast transmission electron microscopy.
Background
Over the last 10 years, numerous studies have been published reporting a small but significant correlation between loneliness and dementia risk. To date, few studies have tested mechanisms ...that mediate the longitudinal association between loneliness and dementia. DNA methylation may be one variable that explains this association, as when combined with other biomarkers, quantifies whether people’s biological age is more (or less) advanced than their chronological age. The purpose of this study is to test whether epigenetic age moderates the longitudinal trajectory of loneliness on dementia risk.
Method
The sample was drawn from the three waves of the Health and Retirement Study (n = 268, mean age = 69) collected four years apart from 2008‐2016. Loneliness scores were composed using with 11 items of the UCLA Loneliness Questionnaire. Dementia risk was quantified according to Langa‐Weir’s approach that uses the modified Telephone Interview for Cognitive Status. Epigenetic age is quantified by DNAm PhenoAge (Levine et al., 2015.). Ordinary least squares regression was used to test the interaction effect of DNAm PhenoAge and loneliness on dementia risk.
Result
A significant interaction effect between DNAmPhenoAge and longitudinal loneliness on dementia risk was found (F(7,268) = 6.98 , p < 0.001; adjusted R2 =.13). Effects of DNAm PhenoAge were greater in those with higher levels of loneliness over time, suggesting that effects of loneliness on dementia risk depend on epigenetic age.
Conclusion
Study results suggest that the longitudinal association between loneliness and dementia risk depends on epigenetic age. One implication of the current results is that the epigenome may be a promising area of study for understanding the processes through which loneliness increases dementia risk.
While chronological age is a strong predictor for health-related risk factors, it is an incomplete metric that fails to fully characterize the unique aging process of individuals with different ...genetic makeup, neurodevelopment, and environmental experiences. Recent advances in epigenomic array technologies have made it possible to generate DNA methylation-based biomarkers of biological aging, which may be useful in predicting a myriad of cognitive abilities and functional brain network organization across older individuals. It is currently unclear which cognitive domains are negatively correlated with epigenetic age above and beyond chronological age, and it is unknown if functional brain organization is an important mechanism for explaining these associations. In this study, individuals with accelerated epigenetic age (i.e. AgeAccelGrim) performed worse on tasks that spanned a wide variety of cognitive faculties including both fluid and crystallized intelligence (N = 103, average age = 68.98 years, 73 females, 30 males). Additionally, fMRI connectome-based predictive models suggested a mediating mechanism of functional connectivity on epigenetic age acceleration-cognition associations primarily in medial temporal lobe and limbic structures. This research highlights the important role of epigenetic aging processes on the development and maintenance of healthy cognitive capacities and function of the aging brain.
Social isolation is one of the strongest predictors of increased risk of mortality in older adulthood. The ability to form and maintain the social relationships that mitigate this risk is partially ...regulated by the oxytocinergic system and one's ability to attend to and process social information. We have previously shown that an epigenetic change to the DNA of the oxytocin receptor gene (
methylation) affects the salience of social information in young adults. Little is known about how the oxytocinergic system ages and what effect this aging system has on social cognitive abilities throughout the lifespan.
Here we explored age-related differences in the association between neural response during selective social attention and
DNA methylation in young (age 18-31) and older (age 58-81) adults. Participants underwent fMRI during a selective social attention task and provided a DNA sample for the assessment of
methylation.
We found that older adults activated diffuse areas of visual cortex and dorsolateral prefrontal cortex during selective social attention, consistent with the dedifferentiation and compensatory neural activation commonly reported in aging. We found a significant age-by-
methylation interaction on neural response when attending to social stimuli in a complex display; young adults displayed a positive association between
methylation and neural activation, replicating our prior finding that young adults with presumed diminished endogenous access to oxytocin recruit regions of the attentional cortex to a greater extent. This association did not hold for older adults. Instead, perceived social support interacted with
methylation to influence neural response during selective social attention. These data suggest that environmental factors like social support moderate biological processes in aging and highlight the importance of a lifespan perspective for understanding associations between individual differences in the oxytocinergic system, neural function, and social behavior.
Abstract We report on the observation of thermal photons from an accelerated electron via examination of radiative beta decay of free neutrons measured by the RDK II collaboration. The emitted photon ...spectrum is shown to corroborate a thermal distribution consistent with the dynamical Casimir effect. Supported by a robust chi-squared statistic, we find the photons reside in a 1D Planck spectrum with a temperature predicted by the moving mirror model. Subject Indices: B50 (Electromagnetic processes and properties), D29 (Nuclear decays and radioactivities (including fission)), and E76 (Quantum field theory on curved space)
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