Advancing Quantum Simulation of the Unruh Effect: Thermal Collapse and Decoherence

The Unruh effect, a fundamental prediction of quantum field theory, posits that an observerundergoing uniform acceleration perceives a thermal bath of particles in a vacuum state, as observedby inertial observers. This study presents a significant advancement in simulating the Unruh effect using IBM’s superconducting quantum processor, ibm_brisbane. By implementing a refinedtwo-qubit quantum circuit that encodes quantum superposition, Bogoliubov transformations, anddecoherence, we achieve a fully thermalized state characterized by maximal entropy (1.0), minimalpurity (0.5), and a fidelity of 0.5 relative to the vacuum state. A distinctive 100% measurementcollapse into the 1 state sets this work apart from prior simulations, confirming complete thermaldecoherence consistent with theoretical predictions. These results establish a new benchmark forrelativistic quantum simulations and provide a scalable framework for exploring related phenomena,such as Hawking radiation and cosmological horizon effects, on near-term quantum hardware