QG1 - Quantum Gravity Phenomenology |
Speaker_ |
Volovik, Grigory |
Talk _ |
Universality classes of fermionic vacua from topology in momentum space |
Abstract _ |
Many quantum condensed matter systems are strongly correlated and strongly interacting fermionic systems, which cannot be treated perturbatively. However, physics which emerges in the low-energy corner does not depend on the complicated details of the system and is relatively simple. It is determined by the nodes in the fermionic spectrum, which are protected by topology in momentum space (in some cases, in combination with the vacuum symmetry). Close to the nodes the behavior of the system becomes universal; and the universality classes are determined by the toplogical invariants in momentum space. Of particular importance for us is the universality class of Fermi points where all the ingredients of Standard Model emerge together with gravity: close to the Fermi point the fermionic quasiparticles behave as relativistic Weyl fermions, while the bososnic collective modes interact with fermions as effective gauge bosons and gravitons. |