报告题目: The Mechanics of Spacetime - A Solid Mechanics Perspective on the Theory of General Relativity

 

报告摘要: We present an elastic constitutive model for gravity where we identify the vacuum of three-dimensional space with a Cosmic Fabric embedded in four-dimensional spacetime and having a small thickness along the time dimension. We show a correspondence between the gravitational phenomena described by General Relativity and the kinematic and kinetic properties of the Cosmic Fabric. We propose, in agreement with modern cosmological observations (Collier, 2012; Perlmutter et al., 1999; Riess et al., 1998) and with theoretical results from Quantum Field Theory (Rugh and Zinkernagel, 2002), that the space vacuum is really not a vacuum in the purest sense but is a Cosmic Fabric that has energy density and as such mass density. We further propose that the Cosmic Fabric deforms due to matter in space, which acts as inclusions, in a manner analogous to the deformation of a conventional thin plate (Efrati et al., 2008). By introducing a constitutive model for General Relativity, we lay the groundwork for subsequently applying Solid Mechanics concepts to Cosmology. In particular, we show that strain along the time dimension manifests as a gravitational potential and contraction along the time dimension as gravitational time dilation. By identifying the action integral based on the elastic energy density of the Cosmic Fabric with the Hilbert-Einstein action integral, we derive an expression for the Cosmic Fabric's elastic modulus in terms of its thickness. Assuming a thickness about a Planck's length, we calculate the elastic modulus and density to be about 10^{113} N m^-2, and 10^{96} kg m^-3, respectively.

Tichomir (Ticho) Tenev received undergraduate degrees in Computer Science, Mathematics, and minor in Physics from MIT in 1996, as well as a Masters of Engineering degree in Computer Science and Electrical Engineering from MIT in 1997. For nearly two decades afterwards, he worked for Silicon Valley companies, where he held top-level technical positions. In his work as a software engineer, Ticho frequently used ideas he gleaned from the design of our Universe, while marveling at the precision, intricacy and self-consistency of its physical laws. So, after a successful carrier as a software engineer, he decided to focus on fundamental research and is presently pursuing a PhD degree in Computational Engineering at Mississippi State University. Ticho’s current research is about the application of Solid Mechanics theory to the theory of General Relativity and Cosmology. He hopes that by bridging these two fields, insights and tools from one would become applicable to the other.