Exact critical exponents for the antiferromagnetic quantum critical point in and dimensions

Speaker: Peter Lunts

When: November 14, 2016 (Mon), 03:15PM to 04:15PM (add to my calendar)
Location: SCI 328

This event is part of the Condensed Matter Theory Seminar Series.

The antiferromagnetic quantum critical point is believed to exist in many unconventional superconductors, such as high-Tc cuprates, heavy fermion compounds and iron-based superconductors. The strange metal state above this critical point is the most common kind of non-Fermi liquid found in nature, and, therefore, gaining a theoretical understanding of it is a key problem in condensed matter. We present a controlled approach to this problem using a dimensional regularization technique, extending the spatial dimension from to . We find an emergent control parameter, which allows us to find exact values for the critical exponents of the theory within a finite window of . We then use these exponents as an ansatz for the problem directly in . We again find the same emergent control parameter, and we confirm that our ansatz is exact in the IR. This gives us an exact description of the low-energy physics, in which both fermions and bosons do not have quasi-particle-like excitations, and the specific heat of the system violates hyperscaling.