Yi Ng

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  • Y J Ng
  • 2001
We show that quantum mechanics and general relativity limit the speed nu of a simple computer (such as a black hole) and its memory space I to I(nu2) less, similar(t(-2))P, where t(P) is the Planck time. We also show that the lifetime of a simple clock and its precision are similarly limited. These bounds and the holographic bound originate from the same(More)
INTRODUCTION The aim of this study was to evaluate the outcome of Osteoplug, a novel biodegradable polymer burr-hole cover implant, used in patients with burr holes done for drainage of chronic subdural haematoma. METHODS 12 patients with chronic subdural haematoma had Osteoplug implants inserted into their burr holes after evacuation of the haematoma.(More)
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 probe Planck-scale physics. In particular, we critically examine the cumulative effects of spacetime fluctuations over a(More)
A recent paper (gr-qc/9909017) criticizes our work on the structure of spacetime foam. Its authors argue that the quantum uncertainty limit for the position of the quantum clock in a gedanken timing experiment, obtained by Wigner and used by us, is based on unrealistic assumptions. Here we point out some flaws in their argument. We also discuss their other(More)
Due to quantum fluctuations, spacetime is foamy on small scales. The degree of foaminess is found to be consistent with the holographic principle. One way to detect spacetime foam is to look for halos in the images of distant quasars. Applying the holographic foam model to cosmology we "predict" that the cosmic energy density takes on the critical value;(More)
We examine the interplay between recent advances in quantum gravity and the problem of turbulence. In particular, we argue that in the gravitational context the phenomenon of turbulence is intimately related to the properties of spacetime foam. In this framework we discuss the relation of turbulence and holography and the interpretation of the Kolmogorov(More)
There is growing interest in quantum-spacetime models in which small departures from Lorentz symmetry are governed by the Planck scale. In particular, several studies have considered the possibility that these small violations of Lorentz symmetry may affect various astrophysical observations, such as the evaluation of the GZK limit for cosmic rays, the(More)
The purpose of this document is to clarify the inductive step described in the proof of Theorem 3.2 in [2]. In the second last sentence of the proof, it says, 'it follows from the inductive proof that R n is of index two.' The question of how this assertion is verified was first raised by Dror Bar Natan and his student Ofer Ron [1]. To avoid any confusions(More)
In this article we study the dynamics of fermions in a fermion-scalar plasma. We begin by obtaining the effective in-medium Dirac equation in real time which is fully renormalized and causal and leads to the initial value problem. For a heavy scalar we find the novel result that the decay of the scalar into fermion pairs in the medium leads to damping of(More)
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