Physics Seminar of the School of Physical Sciences
A Note on Entanglement Entropy, Coherent States and Gravity
Madhavan Varadarajan
(Raman Research Institute, Bengaluru)
April 12, 2017 (Wednesday)
16:00 hrs (4:00 PM)
Seminar Room, First Floor, SPS
Abstract: We review two recent attempts to explain aspects of gravitational physics through changes in entanglement entropy of quantum fields. The first, due to Bianchi, builds on Sorkin's seminal ideas in the 80's and attempts to connect the change in black hole entropy with that of entanglement entropy without recourse to an explicit UV cutoff. The second, due to Jacobson, seeks to derive the equations of gravitational dynamics itself (which relate matter stress energy to spacetime curvature), through a certain maximal entanglement entropy hypothesis. Common to both attempts is the emergence, purely from quantum entanglement, of (changes in) stress energy. On the other hand, we note that the entanglement entropy of a free quantum field in a coherent state is independent of its stress energy content. We explore the tension between this fact and Bianchi's and Jacobson's ideas.