Quantum Memory

Devices that can convert, store, and manipulate quantum information are important components in a variety of quantum technologies, ranging from quantum repeaters for communication, to analogues of RAM in quantum computers.

In our lab, we have been exploring a particular implementation of quantum memory using rubidium atoms, where we make use of the Autler-Townes splitting (ATS) effect to "dress" the atoms dynamically, realizing a fast, efficient, and broadband memory for optical signals.

We have demonstrated the operation of our memories in laser-cooled atoms and BECs, we have shown analogues to beam-splitting operations, and we can operate with both classical-level and single-photon-level signals.

Papers

Harnessing superradiance for fast/broadband quantum memory

In our Quantum Memory project, we explored the regime of fast and broadband signal storage by moving to the superradiant regime of collective emission in the rubidium vapour, where the output signals emit on timescales faster than the atoms' natural lifetime.

  • Anindya Rastogi, Erhan Saglamyurek, Taras Hrushevskyi, Lindsay J. LeBlanc [arxiv.2112.09261]


Storing short single-photon-level optical pulses in Bose-Einstein condensates for high-performance quantum memory

We used a Bose-Einstein condensate of rubidium atoms as the storage medium for the ATS memory, and found that it increased our storage times and can lead to a broadband, efficient quantum memory.

  • E. Saglamyurek, T. Hrushevskyi, A. Rastogi, L. W. Cooke, B. D. Smith, and L. J. LeBlanc. arxiv.org:2010.15069 (2020) [arxiv.org:2010:15780]


Single-photon-level operation of the ATS memory

Using weak, coherent laser pulses with as few as 0.1 photons/pulse on average, we demonstrated a very low-noise version of our ATS quantum memory.

  • E. Saglamyurek, T. Hrushevskyi, L. W. Cooke, A. Rastogi, L. J. LeBlanc. Phys. Rev. Research 1, 022004(R) (2019). [Journal Link][arxiv:1905.05856]

Discerning the differences between the ATS memory protocol and the Electromagnetically-induced transparency (EIT) protocol

The operation of an ATS-protocol memory is not so different from that of a slow-light based EIT memory -- but, the mechanisms are very different. In this paper, we explore the differences between these two atom-based quantum memory protocols and give guidelines for choosing the best protocol for your situation.

  • Anindya Rastogi, Erhan Saglamyurek, Taras Hrushevskyi, Scott Hubele, Lindsay J. LeBlanc, Phys. Rev. A 100, 012314 (2019). [Journal Link][arxiv:1902.02815]


Our first demonstration of ATS memory: a coherent means of storage and manipulation for broadband photons

Using our ensembles of laser-cooled rubidium atoms, we demonstrate that a broadband optical signals can be stored and retrieved coherently. This scheme relies on a coupled three-level system, where the strong "control" field puts us into the Autler-Townes regime. Despite the lack of an analytic solution for the memory process in this regime, we find faithful retrieval of our optical signals in a memory that can be characterized as "fast" or "nonadiabatic," in contrast to previous atomic memory demonstrations.

    • Erhan Saglamyurek, Taras Hrushevskyi, Anindya Rastogi, Khabat Heshami, and Lindsay J. LeBlanc. Nature Photonics, 12, 774–782 (2018).[Journal Link][arxiv:1710.08902]


Posters and other information

(under construction)