Quantum simulation of nonequilibrium dynamics and thermalization in the Schwinger model

We present simulations of nonequilibrium dynamics of quantum field theories on digital quantum computers. As a representative example, we consider the Schwinger model, a (1 thorn 1)-dimensional U(1) gauge theory, coupled through a Yukawa-type interaction to a thermal environment described by a scalar field theory. We use the Hamiltonian formulation of the Schwinger model discretized on a spatial lattice. With the thermal scalar fields traced out, the Schwinger model can be treated as an open quantum system and its real-time dynamics are governed by a Lindblad equation in the Markovian limit. The interaction with the environment ultimately drives the system to thermal equilibrium. In the quantum Brownian motion limit, the Lindblad equation is related to a field theoretical Caldeira-Leggett equation. By using the Stinespring dilation theorem with ancillary qubits, we perform studies of both the nonequilibrium dynamics and the preparation of a thermal state in the Schwinger model using IBM's simulator and quantum devices. The real-time dynamics of field theories as open quantum systems and the thermal state preparation studied here are relevant for a variety of applications in nuclear and particle physics, quantum information and cosmology.

Automated summary

We present simulations of nonequilibrium dynamics of quantum field theories on digital quantum computers, using the Schwinger model as an example. By considering the interaction between the Schwinger model and a thermal environment, we study the open quantum system and its real-time dynamics through a Lindblad equation. With the help of the Stinespring dilation theorem, we explore the nonequilibrium dynamics and thermal state preparation of the Schwinger model using IBM's simulator and quantum devices. The findings have implications for various applications in nuclear and particle physics, quantum information, and cosmology.