Design and Implementation of an Experimental Setup for Entanglement Harvesting

Abstract

Relativistic quantum information is an emerging field of study at the interface of relativity and quantum theories. One key result is the prediction of extracting entanglement from quantum fields known as “entanglement harvesting”. The Superconducting Quantum Devices (SQD) group has recently designed a qubit-coupler system, suitable for generating entanglement between two causally disconnected qubits, and developed an experimental protocol to measure entanglement harvesting.

In this thesis, developments to the experimental infrastructure aimed to facilitate the entanglement harvesting experiment will be presented. The proposed experiment is operated on a superconducting flux qubit device in a dilution refrigerator. We discuss the theoretical requirements for entanglement harvesting and outline the experimental proposal. We propose cryogenic electronics setup capable of providing all the of requirements for entanglement harvesting. We model the thermal state in the transmission line, and propose attenuation that will reach a low enough thermal noise to extract entanglement. We propose electronic cables capable of supplying biasing currents between 0-26.5 GHz, able to provide low dispersion of a 33 ps Gaussian pulse and low heating of static currents up to 5 mA, required for biasing an entanglement harvesting measurement. A new superconducting magnetic coil is designed and constructed, where we consider its impact on experimental operation. The thermal considerations of heating the dilution refrigerator and properly dissipating the heat are presented.