The storage of optical quantum states is a key enabling technology for optical quantum computing and long-range quantum communications.
The primary role of quantum memories is to synchronise quantum states arising from stochastic events, an operation critical for scaling of linear optical quantum computers to a large size and for the operation of quantum repeater communication protocols. Through the creation and manipulation of quantum states within memory there also exists the potential to construct sophisticated quantum processor platforms based on the memory itself.
AT CQC²T we are developing an optical memory platform that readily interfaces to optical communication channels with the required storage times, fidelity, and data capacity for network operations. The quantum memory work in CQC²T takes place in parallel using two complementary platforms, solid-state and atomic gas.
Atomic gas memories is a medium that allows for the rapid development and precise testing of quantum memory and related atom-light protocols. This is because the properties of the atomic ensemble are determined by how we trap the gas, meaning that the ensemble can be tuned and modified on demand. This allows us to experiment with different geometries and optical depths without any significant modification of the system.
The solid-state platform being developed in CQC²T is based on rare-earth doped crystals. This platform has characteristics that make it uniquely suited to implementing repeaters for long range quantum communications. It offers long memory lifetimes, wavelength compatible with optical fibre and satellite optical communications, the potential for high data storage capacity and the ability to be integrated into complex quantum optical circuits as part of planar waveguide and monolithic devices.