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The cosmic time dilation observed in Type Ia supernova light curves suggests that the passage of cosmic time varies throughout the evolution of the Universe. This observation implies that the rate of proper time is not constant, as assumed in the standard FLRW metric, but instead is time-dependent. Consequently, the commonly used FLRW metric should be replaced by a more general framework, known as the Conformal Cosmology (CC) metric, to properly account for cosmic time dilation. The CC metric incorporates both spatial expansion and time dilation during cosmic evolution. As a result, it is necessary to distinguish between comoving and proper (physical) time, similar to the distinction made between comoving and proper distances. In addition to successfully explaining cosmic time dilation, the CC metric offers several further advantages: (1) it preserves Lorentz invariance, (2) it maintains the form of Maxwell’s equations as in Minkowski spacetime, (3) it eliminates the need for dark matter and dark energy in the Friedmann equations, and (4) it successfully predicts the expansion and morphology of spiral galaxies in agreement with observations.

We investigated whether Early Posterior Negativity (EPN) indicated the subjective dilation of time when judging the duration of arousing stimuli. Participants performed a visual temporal bisection task along with high-level and low-level arousing auditory stimuli, while we simultaneously recorded EEG. In accordance with previous studies, arousing stimuli were temporally overestimated and led to higher EPN amplitude. Yet, we observed that time dilation and EPN amplitude were significantly correlated and this effect cannot be explained by confounds from stimulus valence. We interpret our findings in terms of the pacemaker–accumulator model of human timing, and suggest that EPN indicates an arousal-based increasing of the speed of our mental clock.

In special relativity, the time dilation formula has been obtained by particles propagation in a straight line trajectory relative to an observer in motion. Up to now, there are no available formulas for other possible trajectories of particles. However, this paper obtains formulas of time dilation for several trajectories of particle such as parabolic, elliptic, and circular and finds a relatively accurate trajectory. The obtained formulas are employed in order to analyze the time dilation of the muon particles decay. In this paper, it is found that the time dilation of the parabolic and the elliptical trajectories exceed the corresponding results utilizing the standard Lorentz-Einstein time dilation formula. Consequently, if we are able to control the trajectory of unstable particles by some external forces, then their life-times might be increased. Probably, the increase in lifetime via a curved trajectory occurs at lower relative velocity & acceleration energy if compared to the straight line trajectory. In addition, the circular trajectory leads to multiple values of time dilation at certain velocities of an observer in motion, which may give an interpretation of fluctuations of time dilation in quantum mechanics. The result arises from the present relatively accurate formula of time dilation that is very close to the experimental data of muon decay (CERN experiment) when it is compared to the result obtained by the Lorentz-Einstein formula. Finally, it may be concluded that the time dilation not only depends on relative velocity and acceleration energy of particles but also on curved trajectories. The present work may attract other researchers to study different trajectories.

Both quantum mechanics and general relativity are based on principles that defy our daily intuitions, such as time dilation, quantum interference and entanglement. Because the regimes where the two theories are typically tested are widely separated, their foundational principles are rarely jointly studied. Recent works have found that novel phenomena appear for quantum particles with an internal structure in the presence of time dilation, which can take place at low energies and in weak gravitational fields. Here we briefly review the effects of time dilation on quantum interference and generalize the results to a variety of systems. In addition, we provide an extended study of the basic principles of quantum theory and relativity that are of relevance for the effects and also address several questions that have been raised, such as the description in different reference frames, the role of the equivalence principle and the effective irreversibility of the decoherence. The manuscript clarifies some of the counterintuitive aspects arising when quantum phenomena and general relativistic effects are jointly considered.

BackgroundBenign esophageal strictures are a frequent complication after esophageal surgery or extensive endoscopic submucosal dissection. Endoscopic dilation is the preferred treatment in clinical practice. However, the allocation of time for each dilation is unclear. The aim of this study was to evaluate the appropriate duration of endoscopic dilation for benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection.MethodsPatients with benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection between July 2010 and July 2018 were retrospectively included in this study. According to the dilation time (1, 3, 5 min), patients were divided into three groups. The clinical effects and adverse events were compared among the three groups.ResultsAltogether, 57 patients, including 21 in the 1-min group, 18 in the 3-min group and 18 in the 5-min group, were included. All patients underwent endoscopic treatment successfully. The stricture recurrence rate was 76.19% in the 1-min group, 55.56% in the 3-min group and 61.11% in the 5-min group. The median overall dysphagia-free period was 2.60 (range, 0.80–12.00) months in the 1-min group, 6.60 (range, 1.80–12.00) months in the 3-min group and 6.25 (range, 2.40–12.00) months in the 5-min group (P < 0.05). For patients who developed stricture recurrence, the mean dysphagia-free periods were 2.26  ±  1.27 months, 4.00  ±  1.76 months and 4.23  ±  1.63 months, respectively (P < 0.05). The dysphagia-free periods were comparable between the 3- and 5-min groups and were longer than those in the 1-min group. Muscle layer damage occurred in two patients (11.11%) in the 5-min group and in no patients in the other two groups.ConclusionThree minutes was considered a safe and effective dilation duration for benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection.

Our experience of time is strikingly plastic: Depending on contextual factors, the same objective duration can seem to fly by or drag on. Perhaps the most direct demonstration of such subjective time dilation is the oddball effect : when seeing identical objects appear one after another, followed by an “oddball” (e.g., a disc that suddenly grows in size, in a sequence of otherwise static discs), observers experience this oddball as having lasted longer than its nonoddball counterparts. Despite extensive work on this phenomenon, a surprisingly foundational question remains unasked: What actually gets dilated? Beyond the oddball, are the objects just before (or just after) the oddball also dilated? As in previous studies, observers viewed sequences of colored discs, one of which could be the oddball—and subsequently reproduced the oddball’s duration. Unlike previous studies, however, there were also critical trials in which observers instead reproduced the duration of the disc immediately before or after the oddball. A clear pattern emerged: oddball-induced time dilation extended to the post-oddball disc, but not the pre-oddball disc. Whence this temporal asymmetry? We suggest that an oddball’s sudden appearance may induce uncertainty about what will happen next, heightening attention until after the uncertainty is resolved.

The perceived duration of time does not veridically reflect the physical duration but is distorted by various factors, such as the stimulus magnitude or the observer’s emotional state. Here, we showed that knowledge about an event’s termination time is another significant factor. We often experience time passage differently when we know that an event will terminate soon. To quantify this, we asked 33 university students to report a rotating clock hand’s duration with or without a termination cue that indicated the position at which the clock hand disappeared. The results showed that the presence of the termination cue dilated perceived durations, and the dilating effect was larger when the stimulus duration was longer, or the speed of the rotating stimulus was slower. A control experiment with a start-cue excluded the possibility that the cue’s mere existence caused the results. Further computational analyses based on the attention theory-of-time perception revealed that the size of dilation is best explained by neither an event’s duration nor the distance traveled by the clock hand, but by how long the clock hand spends time near the termination cue. The results imply that an event-termination cue generates a field in which the perceived time dilates.

Background A recent meta-analysis left open a significant question regarding altered time perception in depression: Why do depressed people overproduce short durations and under-produce longer durations if their present experience is that time flows slowly? Experience and judgement of time do not seem to accord with one another. Analysis By excluding two of the six studies on methodological grounds from a previous meta-analysis of medium-length interval productions, and re-analysing the remaining four studies, the present paper finds that subjective time accelerates from initial dilation within present experience (approximately 1 s duration) to subsequent acceleration within working memory (approximately 30 s duration) when depressed. Proposals It is proposed that depressive time dilation and acceleration refer to the default mode and central executive networks, respectively. The acceleration effect is suggested to occur due to mood congruency between long intervals, boredom, and depression. This mood congruency leads to the automatic recall of intrusive, negative, and non-specific autobiographical long-term memories used to judge intervals from previous experience. Acceleration in working memory then occurs according to the contextual change model of duration estimation. Limitations The meta-analysis is limited to four studies only, but provides a potential link between time experience and judgement within the same explanatory model. Conclusions Similarities between psychological time dilation/acceleration and physical time dilation/acceleration are discussed.

Debate over the issue of the rate of the passage of time has been persisting in the academic literature for decades without substantial progress. The common explanations of the (empirically well-confirmed) time dilation effects from Special and General Relativity theories requires that there is a physical passage of time which occurs at varying rates. Yet, these theories do not formally posit any passage of time. It is shown that the relativistic time dilation effects strongly imply that the passage of time is not a physical phenomenon. El debate sobre el ritmo del paso del tiempo ha persistido en la literatura académica durante décadas sin progreso sustantivo. La explicación habitual de los (empíricamente confirmados) efectos de dilatación temporal a partir de las teorías de la relatividad especial y general requiere que haya un paso del tiempo que transcurra a ritmos variables. Sin embargo, estas teorías no postulan formalmente ningún paso del tiempo. En este artículo se muestra que los efectos relativistas de dilatación temporal implican con fuerza que el paso del tiempo no es un fenómeno físico.

Inspired by the recent literature, we study the Einstein–de Sitter cosmological model coupled with a generalization of the relation between the redshift and time dilation of the kind δt0=δte(1+z)n. We find that this model fits the experimental data regarding 1048 supernovae, in a way which is competitive with the standard ΛCDM model and without the need of introducing a non-zero cosmological constant. Since the existence of dark energy, as a main ingredient of the composition of the cosmos, is still under debate, we propose our formalism as an example of an alternative description of the cosmological scenario.