Speaker
Description
We propose a qubit-based framework for quantum simulations of quantum field theories in curved spacetimes using quantum spin systems. Starting from a spin-1/2 Hamiltonian with spatially and temporally varying exchange couplings and magnetic fields, we first map the system through the Jordan-Wigner transformation to a lattice Hamiltonian of Majorana fermions. Taking the continuum limit, the lattice fermion model reproduces Majorana quantum field theories on general two-dimensional curved spacetimes. This establishes a direct correspondence between spacetime geometry and experimentally controllable parameters in quantum devices, while naturally connecting qubit systems and Hamiltonian lattice-fermion formulations of curved-spacetime quantum field theories.
Using this framework, we study several gravitational quantum phenomena, including particle production in expanding universes described by Friedmann-Lemaître-Robertson-Walker spacetimes, quantum field dynamics in de Sitter spacetimes, and black-hole physics such as Hawking radiation. These examples demonstrate that qubit-based quantum simulators can provide a versatile platform for investigating nonequilibrium quantum phenomena associated with curved spacetimes and horizons. Our framework opens a route toward “tabletop universe” simulations of gravitational quantum phenomena using near-term quantum devices.