Quantum spin dynamics group
Oxford Materials Oxford Physics
University of Oxford home page
Our research
The magnetic moments of nuclei, atoms and molecules in condensed matter can exhibit strongly quantum behaviour, with discrete energy levels and weak coupling to other degrees of freedom. We study the dynamics of these systems, principally using magnetic resonance, to establish...
  • how best to exploit spins in condensed matter for quantum information applications;
  • the environment of the spin, which can tell us about materials properties, molecular structures, conformation changes, and relaxation mechanisms;
  • the interaction of spins with other excitations, to allow detection of magnetic resonance through optical or transport phenomena;
  • and more!
Reflecting the interdisciplinary nature of our research, our group spans the interface between the Departments of Materials and of Physics at Oxford.
For enquiries about the group, please contact:
Dr Arzhang Ardavan (group leader),
Dr John JL Morton (group leader),
 
News stories

'Caging Schrödinger's cat' - Quantum nanotechnology podcast filmed
in our Pulsed EPR lab

 

Recent results
  • Schrödinger's cat o' nine tails whips sensors into shape

    Quantum entangled states can be very delicate and easily perturbed by their external environment. This sensitivity can be harnessed in measurement technology to create a quantum sensor with a capability of outperforming conventional devices at a fundamental level. We compare the magnetic field sensitivity of a classical (unentangled) system with that of a 10-qubit entangled state, realised by nuclei in a highly symmetric molecule. We observe a 9.4-fold quantum enhancement in the sensitivity to an applied field for the entangled system and show that this spin-based approach can scale favorably compared to approaches where qubit loss is prevalent. This result demonstrates a method for practical quantum field sensing technology.
     

    Magnetic field sensing beyond the standard quantum limit using 10-spin NOON states

    Jonathan A. Jones, Steven D. Karlen, Joseph Fitzsimons, Arzhang Ardavan, Simon C. Benjamin, G. Andrew D. Briggs and John J.L. Morton,,
    Science 324 1166 (2009) Link
  • Memoirs of a silicon qubit: coherent storage beyond a second

    A powerful model for quantum computation is thus one in which electron spins are used for processing and readout while nuclear spins are used for storage. We have demonstrated the coherent transfer of a superposition state in an electron spin 'processing' qubit to a nuclear spin 'memory' qubit, using a combination of microwave and radiofrequency pulses applied to 31P donors in an isotopically pure 28Si crystal. The electron spin state can be stored in the nuclear spin on a timescale that is long compared with the electron decoherence time and then coherently transferred back to the electron spin, thus demonstrating the 31P nuclear spin as a solid-state quantum memory. The coherence lifetime of the quantum memory element is found to exceed one second at 5.5K.
     

    Solid state quantum memory using the 31P nuclear spin

    John J. L. Morton, Alexei M. Tyryshkin, Richard M. Brown, Shyam Shankar, Brendon W. Lovett, Arzhang Ardavan, Thomas Schenkel, Eugene E. Haller, Joel W. Ager, S. A. Lyon,
    Nature 455 1085 (2008) Link
 
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