Talk on Geometry of Krylov Complexity

Event Details:

  • Date: [25 September 2023]
  • Time: [02:00 PM IST to 04:00 PM IST]
  • Venue: Vindhya A3-117

Event Description

Hello,

We will have a slightly advanced talk from Vivek Pandey, a PhD student at Harish-Chandra Research Institute.

Speaker: Vivek Pandey

Title: Geometry of Krylov Complexity

Ref: https://arxiv.org/abs/2109.03824

Abstract:

We develop a geometric approach to operator growth and Krylov complexity in many-body quantum systems governed by symmetries. We start by showing a direct link between a unitary evolution with the Liouvillian and the displacement operator of appropriate generalized coherent states. This connection maps operator growth to a purely classical motion in phase space. The phase spaces are endowed with a natural information metric. We show that, in this geometry, operator growth is represented by geodesics and Krylov complexity is proportional to a volume. This geometric perspective also provides two novel avenues towards computation of Lanczos coefficients and sheds new light on the origin of their maximal growth. We describe the general idea and analyze it in explicit examples among which we reproduce known results from the Sachdev-Ye-Kitaev model, derive operator growth based on SU(2) and Heisenberg-Weyl symmetries, and generalize the discussion to conformal field theories. Finally, we use techniques from quantum optics to study operator evolution with quantum information tools such as entanglement and Renyi entropies, negativity, fidelity, relative entropy and capacity of entanglement.

Hoping to see you all at the talk.

Cheers,

ISAQC team.