MEASURING AND CHARACTERIZING THE QUANTUM METRIC TENSOR Michael Kolodrubetz, Physics Department, Boston University Equilibration and Thermalization Conference, Stellenbosh, April In collaboration with: Anatoli Polkovnikov (BU) and Vladimir Gritsev (Fribourg) Talk to me about: - Thermalization and dephasing in Kibble-Zurek - Real-time dynamics from non- equilibrium QMC
OUTLINE Definition of the metric tensor Measuring the metric tensor Noise-noise correlations Corrections to adiabaticity Classification of quantum geometry XY model in a transverse field Geometric invariants Euler integrals Gaussian curvature Classification of singularities Conclusions
FUBINI-STUDY METRIC
Berry connection
FUBINI-STUDY METRIC Berry connection Metric tensor
FUBINI-STUDY METRIC Berry connection Metric tensor Berry curvature
MEASURING THE METRIC
Generalized force
MEASURING THE METRIC Generalized force
MEASURING THE METRIC Generalized force
MEASURING THE METRIC Generalized force
MEASURING THE METRIC
For Bloch Hamiltonians, Neupert et al. pointed out relation to current-current noise correlations [arXiv: ]
MEASURING THE METRIC For Bloch Hamiltonians, Neupert et al. pointed out relation to current-current noise correlations [arXiv: ] Generalizable to other parameters/non-interacting systems
MEASURING THE METRIC For Bloch Hamiltonians, Neupert et al. pointed out relation to current-current noise correlations [arXiv: ] Generalizable to other parameters/non-interacting systems
MEASURING THE METRIC
REAL TIME
MEASURING THE METRIC REAL TIME IMAG. TIME
MEASURING THE METRIC REAL TIME IMAG. TIME
MEASURING THE METRIC REAL TIME IMAG. TIME
MEASURING THE METRIC Real time extensions:
MEASURING THE METRIC Real time extensions:
MEASURING THE METRIC Real time extensions:
MEASURING THE METRIC Real time extensions:
MEASURING THE METRIC Real time extensions: (related the Loschmidt echo)
VISUALIZING THE METRIC
Transverse field Anisotropy Global z-rotation
VISUALIZING THE METRIC Transverse field Anisotropy Global z-rotation
VISUALIZING THE METRIC
h- plane
VISUALIZING THE METRIC h- plane
VISUALIZING THE METRIC h- plane
VISUALIZING THE METRIC - plane
VISUALIZING THE METRIC - plane
VISUALIZING THE METRIC No (simple) representative surface in the h- plane - plane
GEOMETRIC INVARIANTS Geometric invariants do not change under reparameterization Metric is not a geometric invariant Shape/topology is a geometric invariant Gaussian curvature K Geodesic curvature k g additional/curvature/curvature19.html
GEOMETRIC INVARIANTS Gauss-Bonnet theorem:
GEOMETRIC INVARIANTS Gauss-Bonnet theorem:
GEOMETRIC INVARIANTS Gauss-Bonnet theorem:
GEOMETRIC INVARIANTS Gauss-Bonnet theorem: 1 0 1
GEOMETRIC INVARIANTS - plane
GEOMETRIC INVARIANTS - plane
GEOMETRIC INVARIANTS - plane Are these Euler integrals universal? YES! Protected by critical scaling theory
GEOMETRIC INVARIANTS - plane Are these Euler integrals universal? YES! Protected by critical scaling theory
SINGULARITIES OF CURVATURE -h plane
INTEGRABLE SINGULARITIES KhKh h h KhKh
CONICAL SINGULARITIES
Same scaling dimesions (not multi-critical)
CONICAL SINGULARITIES Same scaling dimesions (not multi-critical)
CURVATURE SINGULARITIES
CONCLUSIONS Measuring the metric tensor Proportional to integrated noise-noise correlations Leading order non-adiabatic corrections to generalized force Classification of quantum geometry Geometry is characterized by set of invariants Gaussian curvature (K) Geodesic curvature (k g ) Singularities of XY model are classified as Integrable Conical Curvature Singularities and integrals are protected