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Extra-galactic sources of photons have been used to constrain space-time quantum fluctuations in the Universe. In these proposals, the fundamental "fuzziness" of distance caused by space-time quantum fluctuations has been directly…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Yanbei Chen , Linqing Wen , Yiqiu Ma

It was recently proposed to use extra-galactic point sources to constrain space-time quantum fluctuations in the universe. In these proposals, the fundamental "fuzziness" of distance caused by space-time quantum fluctuations have been…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Yanbei Chen , Linqing Wen

One aspect of the quantum nature of spacetime is its "foaminess" at very small scales. Many models for spacetime foam are defined by the accumulation power $\alpha$, which parameterizes the rate at which Planck-scale spatial uncertainties…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Eric S. Perlman , Saul A. Rappaport , Wayne A. Christensen , Y. Jack Ng , John DeVore , David Pooley

At Planck-scale, spacetime is "foamy" due to quantum fluctuations predicted by quantum gravity. Here we consider the possibility of using spacetime foam-induced phase incoherence of light from distant galaxies and gamma-ray bursters to…

Astrophysics · Physics 2009-11-07 Y. Jack Ng , W. A. Christiansen , H. van Dam

The space-time metric is widely believed to be subject to stochastic fluctuations induced by quantum gravity at the Planck scale. This work is based on two different phenomenological approaches being currently made to this topic, and…

Astrophysics · Physics 2009-11-07 R. Le Gallou

Using a \emph{gedanken} experiment providing presumably a minimal inaccuracy the uncertainty contributions to the space-time measurement are precisely evaluated for clock and mirror respectively. The resulting expression of minimal…

High Energy Physics - Phenomenology · Physics 2007-05-23 Michael Maziashvili

Plausibly spacetime is "foamy" on small distance scales, due to quantum fluctuations. We elaborate on the proposal to detect spacetime foam by looking for seeing disks in the images of distant quasars and AGNs. This is a null test in the…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-22 Wayne A. Christiansen , David J. E. Floyd , Y. Jack Ng , Eric S. Perlman

One of the most common expectations of a quantum theory of gravity is that space-time is uncertain or fluctuating at microscopic scales, making it a stochastic medium for particle propagation. Particles traversing this space-time may…

High Energy Physics - Phenomenology · Physics 2022-01-19 Thomas Stuttard

Several approaches to the quantum-gravity problem predict that spacetime should be "fuzzy", but have been so far unable to provide a crisp physical characterization of this notion. An intuitive picture of spacetime fuzziness has been…

High Energy Physics - Theory · Physics 2013-04-30 Giovanni Amelino-Camelia , Valerio Astuti , Giacomo Rosati

In papers on primary state diffusion (Percival 1994, 1995), numerical estimates suggested that fluctuations in the space-time metric on the scale of the Planck time (10^-44s) could be detected using atom interferometers. In this paper we…

Quantum Physics · Physics 2009-10-30 Ian C. Percival , Walter T. Strunz

Planck-scale quantum spacetime undergoes probabilistic local curvature fluctuations whose distributions cannot explicitly depend on position otherwise vacuum's small-scale quantum structure would fail to be statistically homogeneous. Since…

High Energy Physics - Theory · Physics 2012-03-28 Christopher D. Burton

In the process of work it has been found that space-time quantum fluctuations are naturally described in terms of the deformation parameter introduced on going from the well-known quantum mechanics to that at Planck scales and put forward…

General Physics · Physics 2013-06-13 A. E. Shalyt-Margolin

Quantum fluctuations can endow spacetime with a foamy structure. In this review article we discuss our various proposals to observationally constrain models of spacetime foam. One way is to examine if the light wave-front from a distant…

General Relativity and Quantum Cosmology · Physics 2022-07-12 Y. Jack Ng , Eric S. Perlman

The starting point of this work is the axiomatic existence of a smallest measurable interval, viz. the Planck time $t_P$, set by quantum fluctuations in the vacuum metric tensor. By the Relativity Principle, the same limit must then apply…

Astrophysics · Physics 2009-11-07 Richard Lieu

If spacetime undergoes quantum fluctuations, an electromagnetic wavefront will acquire uncertainties in direction as well as phase as it propagates through spacetime. These uncertainties can show up in interferometric observations of…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Y. Jack Ng

We present a method of directly testing whether time continues to have its usual meaning on scales of <= t_P = sqrt(hbar G/c^5) ~ 5.4E-44 s, the Planck time. According to quantum gravity, the time t of an event cannot be determined more…

Astrophysics · Physics 2009-11-07 Richard Lieu , Lloyd W. Hillman

Due to quantum fluctuations, spacetime is foamy on small scales. For maximum spatial resolution of the geometry of spacetime, the holographic model of spacetime foam stipulates that the uncertainty or fluctuation of distance $l$ is given,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Michele Arzano , Thomas W. Kephart , Y. Jack Ng

The spectrograph ESPRESSO recently obtained a limit on the variation of the fine-structure constant, $\alpha$, through measurements along the line of sight of a bright quasar with a precision of $1.36$ ppm at $1\sigma$ level. This imposes…

It is generally expected that quantum gravity affects the structure of space-time by introducing stochastic fluctuations in the geometry, and, ultimately, in the measurements of four-distances and four-momenta.These fluctuations may induce…

Astrophysics · Physics 2007-05-23 R. Aloisio , P. Blasi , A. Galante , P. L. Ghia , A. F. Grillo

The quantum model of homogeneous and isotropic universe filled with the uniform scalar field is considered. This model predicts effective inverse square-law dependence of the mean total energy density <\rho> on the expectation value of…

Astrophysics · Physics 2007-05-23 V. E. Kuzmichev , V. V. Kuzmichev
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