Quantum Information & Computing Meeting: Simulatability phase transitions in dynamics of locally interacting open quantum spin systems

Rahul Trivedi (MPQ):
For a continuous time model of spins on d-dimensional lattices with local interaction interrupted by entanglement breaking noise occurring as per poissonian process, I will show that a classical polynomial time algorithm can be used to sample from the density matrix of the spins after O(poly(n)) time.

Rahul Trivedi (MPQ)
Hybrid group seminar: Theory Seminar Room B2.26/Zoom
Tue, 5. October 2021, 10:45 am (MEZ)

Abstract:

I will discuss two results:

1. For a continuous time model of spins on d-dimensional lattices with local interaction interrupted by entanglement breaking noise occurring as per poissonian process, I will show that a classical polynomial time algorithm can be used to sample from the density matrix of the spins after O(poly(n)) time.
2. I will discuss some implication of the threshold theorem on the simulatability of continuous time and discrete time spin systems below the noise threshold. In particular, I will show that if the noise channel allows for a fixed point separate from identity (for discrete time models) or has a range not containing identity (for continuous time model), there will exist a noise threshold below which simulating the dynamics of the spin system after Omega(poly(n)) time is BQP hard.