96
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Quantum-Spacetime Phenomenology

      Living Reviews in Relativity
      Springer
      quantum spacetime, loop quantum gravity, spacetime noncommutativity

      Read this article at

      ScienceOpenPublisherPMC
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          I review the current status of phenomenological programs inspired by quantum-spacetime research. I stress in particular the significance of results establishing that certain data analyses provide sensitivity to effects introduced genuinely at the Planck scale. My main focus is on phenomenological programs that affect the directions taken by studies of quantum-spacetime theories.

          Related collections

          Most cited references472

          • Record: found
          • Abstract: found
          • Article: found
          Is Open Access

          The Hierarchy Problem and New Dimensions at a Millimeter

          We propose a new framework for solving the hierarchy problem which does not rely on either supersymmetry or technicolor. In this framework, the gravitational and gauge interactions become united at the weak scale, which we take as the only fundamental short distance scale in nature. The observed weakness of gravity on distances \(\gsim\) 1 mm is due to the existence of \(n \geq 2\) new compact spatial dimensions large compared to the weak scale. The Planck scale \(M_{Pl} \sim G_N^{-1/2}\) is not a fundamental scale; its enormity is simply a consequence of the large size of the new dimensions. While gravitons can freely propagate in the new dimensions, at sub-weak energies the Standard Model (SM) fields must be localized to a 4-dimensional manifold of weak scale "thickness" in the extra dimensions. This picture leads to a number of striking signals for accelerator and laboratory experiments. For the case of \(n=2\) new dimensions, planned sub-millimeter measurements of gravity may observe the transition from \(1/r^2 \to 1/r^4\) Newtonian gravitation. For any number of new dimensions, the LHC and NLC could observe strong quantum gravitational interactions. Furthermore, SM particles can be kicked off our 4 dimensional manifold into the new dimensions, carrying away energy, and leading to an abrupt decrease in events with high transverse momentum \(p_T \gsim\) TeV. For certain compact manifolds, such particles will keep circling in the extra dimensions, periodically returning, colliding with and depositing energy to our four dimensional vacuum with frequencies of \( \sim 10^{12}\) Hz or larger. As a concrete illustration, we construct a model with SM fields localised on the 4-dimensional throat of a vortex in 6 dimensions, with a Pati-Salam gauge symmetry \(SU(4) \times SU(2) \times SU(2)\) in the bulk.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            Noncommutative Field Theory

            We review the generalization of field theory to space-time with noncommuting coordinates, starting with the basics and covering most of the active directions of research. Such theories are now known to emerge from limits of M theory and string theory, and to describe quantum Hall states. In the last few years they have been studied intensively, and many qualitatively new phenomena have been discovered, both on the classical and quantum level. To appear in Reviews of Modern Physics.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Thermodynamics of Spacetime: The Einstein Equation of State

              The Einstein equation is derived from the proportionality of entropy and horizon area together with the fundamental relation \(\delta Q=TdS\) connecting heat, entropy, and temperature. The key idea is to demand that this relation hold for all the local Rindler causal horizons through each spacetime point, with \(\delta Q\) and \(T\) interpreted as the energy flux and Unruh temperature seen by an accelerated observer just inside the horizon. This requires that gravitational lensing by matter energy distorts the causal structure of spacetime in just such a way that the Einstein equation holds. Viewed in this way, the Einstein equation is an equation of state. This perspective suggests that it may be no more appropriate to canonically quantize the Einstein equation than it would be to quantize the wave equation for sound in air.
                Bookmark

                Author and article information

                Journal
                5255913
                10.12942/lrr-2013-5
                Unknown

                quantum spacetime,loop quantum gravity,spacetime noncommutativity

                Comments

                Comment on this article