A Hybrid Atom-Photon-Superconductor Quantum Interface

Project: Research Fellowship

Project Details


"The field of quantum information arises from a desire to overcome the challenges of solving complex or intractable problems on classical computers by harnessing quantum mechanics to provide efficient and scalable algorithms. Whilst there has been tremendous recent progress in the realisation of small-scale quantum circuits comprising several quantum bits ("qubits''), research indicates that a fault-tolerant quantum computer capable of harnessing the power of quantum mechanics will require a network of thousands of qubits. This goal is presently beyond the reach of any existing implementation based on a single physical qubit type.

Hybrid quantum information processing is an alternative approach that exploits the unique strengths of disparate quantum technologies, and offers a route to overcome the drawbacks associated with of a single-qubit architecture in direct analogy to the design of classical computing hardware. This proposal aims to combine three different technologies:

i) Superconducting circuits, with very fast (10 ns) gate times for fast processing,
ii) Neutral atoms, with long (10 s) coherence times for long lived quantum memory,
iii) Optical photons, for long distance fibre communication,

to create a novel hybrid quantum interface capable of storing, processing and generating highly entangled states of photons for quantum networking and cryptography applications, overcoming the short coherence time associated with the scalable superconducting circuit systems. This also offers applications in quantum metrology for conversion from optical to microwave domain quantum information, making it possible to extend the interface to incorporate a wide range of alternative solid-state based qubits.

The interface relies on use of highly excited Rydberg states, which have incredibly large dipole moments and transitions in the microwave regime, which can resonantly couple to superconducting qubits embedded in planar microwave waveguide cavities. The large Rydberg dipole also leads to strong, controllable interactions between atoms to provide a collective enhancement in the coupling to single photons for efficient storage and retrieval of light.

The first stage of the experiment is to trap spatially addressable atomic ensembles above a superconducting microwave resonator operating at 4 K to demonstrate strong coupling to the waveguide mode, a key milestone for implementing the hybrid interface. The ensembles will then be utilised to perform coherent storage and retrieval of optical photons, as well as generation of single photons using four-wave mixing.

The second stage is to exploit the off-resonant interaction with the cavity to achieve controllable long distance (~1 cm) entanglement between a pair of ensembles trapped within a single microwave resonator. This will then be used to generate entangled photon pairs, exploring the benefits of collective encoding within the ensembles for achieving entanglement in the polarisation degrees of freedom for long-distance cryptographic quantum key distribution. The resulting hybrid quantum interface provides an ideal building block for establishing quantum networks. Long term this can be integrated with existing superconducting qubit technologies, making a significant step towards the realisation of scalable quantum computing."
Effective start/end date1/07/1530/06/20


  • EPSRC (Engineering and Physical Sciences Research Council): £751,013.00

Research Output

Coherent control of addressable Rydberg atoms for hybrid quantum information processing

Picken, C. J., Legaie, R., McDonnell, K. & Pritchard, J. D., 25 Jul 2018. 1 p.

Research output: Contribution to conferencePoster

Open Access
16 Downloads (Pure)

Entanglement of neutral-atom qubits with long ground-Rydberg coherence times

Picken, C. J., Legaie, R., McDonnell, K. & Pritchard, J. D., 3 Dec 2018, In : Quantum Science and Technology. 4, 1, 8 p., 015011.

Research output: Contribution to journalArticle

Open Access
  • 19 Citations (Scopus)
    12 Downloads (Pure)

    Sub-kilohertz excitation lasers for quantum information processing with Rydberg atoms

    Legaie, R., Picken, C. J. & Pritchard, J. D., 22 Mar 2018, In : Journal of the Optical Society of America B. 35, 4, p. 892-898 7 p.

    Research output: Contribution to journalArticle

    Open Access
    5 Citations (Scopus)
    61 Downloads (Pure)


    Data for "Single Atom Imaging with an sCMOS camera"

    Pritchard, J. (Creator), Picken, C. J. (Creator) & LEGAIE, R. (Creator), University of Strathclyde, 11 Sep 2017


    Sub-kHz linewidth lasers for Quantum Information Processing with Rydberg atoms

    Pritchard, J. (Creator), LEGAIE, R. (Creator) & Picken, C. J. (Creator), University of Strathclyde, 2 Nov 2017



    Quantum Technology Fellowship

    Pritchard, Jonathan (Recipient), 9 Jun 2015

    Prize: Fellowship awarded competitively


    • 1 Types of Public engagement and outreach - Media article or participation
    • 1 Invited talk
    • 1 Oral presentation

    BBC Article on neutral atom quantum computing

    Jonathan Pritchard (Interviewee) & Andrew Daley (Interviewee)

    7 Aug 2020

    Activity: Other activity typesTypes of Public engagement and outreach - Media article or participation

    Progress towards a hybrid Atom- Superconductor Interface for Quantum Networking

    Jonathan Pritchard (Speaker)

    1 Oct 2018

    Activity: Talk or presentation typesOral presentation

    Progress towards a hybrid atom-superconductor interface for quantum networking

    Jonathan Pritchard (Speaker)

    13 Sep 2017

    Activity: Talk or presentation typesInvited talk