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.

Platform Leaders

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Featured Publications

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Initialization protocol for efficient quantum memories using resolved hyperfine structure JS Stuart, M Hedges, R Ahlefeldt, M Sellars Physical Review Research, 3, L032054 (2021)
Stationary Light in Atomic Media JL Everett, DB Higginbotham, GT Campbell, PK Lam, BC Buchler Advanced Quantum Technologies, 2, 1800100 (2019)
Multiparameter optimisation of a magneto-optical trap using deep learning A. D. Tranter, H. J. Slatyer, M. R. Hush, A. C. Leung, J. L. Everett, K. V. Paul, P. Vernaz-Gris, P. K. Lam, B. C. Buchler & G. T. Campbell Nature Communications, 9, 4360 (2018)
Dynamical observations of self-stabilizing stationary light JL Everett, GT Campbell, Y-W Cho, P Vernaz-Gris, DB Higginbottom, O Pinel, NP Robins, PK Lam and BC Buchler Nature Physics, 13, 68 (2016)
Unconditional room-temperature quantum memory M. Hosseini, G. Campbell, B.M. Sparkes, P.K. Lam and B.C. Buchler Nature Physics, 7, 794 (2011)
High efficiency coherent optical memory with warm rubidium vapour M. Hosseini, B.M. Sparkes, G. Campbell, P.K. Lam and B.C. Buchler Nature Communications, 2, 174 (2011)
Generation of light with multimode time-delayed entanglement using storage in a solid-state spin-wave quantum memory KR Ferguson, SE Beavan, JJ Longdell and MJ Sellars Physical Review Letters, 117, 20501 (2016)
Observation of Photon Echoes From Evanescently Coupled Rare-Earth Ions in a Planar Waveguide S. Marzban, J.G. Bartholomew, S. Madden, K. Vu and M.J. Sellars Physical Review Letters, 115, 13601 (2015)
Coherence time of over a second in a telecom-compatible quantum memory storage material M Rančić, MP Hedges, RL Ahlefeldt and MJ Sellars Nature Physics, 14, 50-54 (2018)
Optically addressable nuclear spins in a solid with a six-hour coherence time M. Zhong, M.P. Hedges, R.L. Ahlefeldt, J.G. Bartholomew, S.E. Beavan, S.M. Wittig, J.J. Longdell and M.J. Sellars Nature, 517, 177 (2015)
Efficient quantum memory for light Morgan P. Hedges, Jevon J. Longdell, Yongmin Li & Matthew J. Sellars Nature, 465, 1052 (2010)
Highly efficient optical quantum memory with long coherence time in cold atoms Y.-W. Cho, G. T. Campbell, J. L. Everett, J. Bernu, D. B. Higginbottom, M. T. Cao, J. Geng, N. P. Robins, P. K. Lam, and B. C. Buchler Optica, 3, 100 (2016)

videos

Materials tutorial: Light matter as a platform for quantum computing

September 20, 2021

Building blocks for a global quantum internet from ANU

September 20, 2021

Quantum computing a step closer to reality with stationary light from ANU

September 20, 2021