Split-ring polariton condensates as macroscopic two-level quantum systems
Yan Xue, Igor Yu. Chestnov, Evgeny Sedov +5 more
Superposition states of circular currents of exciton-polaritons mimic the superconducting flux qubits.The phase of a polariton fluid must change by an integer number of 2π when going around the ring.If one introduces a π -phase delay line in the ring, the fluid is obliged to propagate a clockwise or anticlockwise circular current to reduce the total phase gained over one round trip to zero or to build it up to 2π .We show that such a π -delay line can be provided by a dark soliton pinned to a potential well created by a C-shape nonresonant pump spot.The resulting split-ring polariton condensates exhibit pronounced coherent oscillations passing periodically through clockwise and anticlockwise current states.These oscillations may persist far beyond the coherence time of polariton condensates.The qubits based on split-ring polariton condensates are expected to possess very high figures of merit that makes them a valuable alternative to superconducting qubits.The use of the dipole-polarized polaritons allows one to control coherently the state of the qubit with the external electric field.This is shown to be one of the tools for realization of single-qubit logic operations.We propose the design of an iSWAP gate based on a pair of coupled polariton qubits.To demonstrate the capacity of the polariton platform for quantum computations, we propose a protocol for the realization of Deutsch's algorithm with polariton qubit networks.
arXiv:1907.00383•Physical Review Research•Jan 29, 2021•60 citations