Schuster Lab

Electrons embedded in the solid-state are ideal quantum memory elements with long coherence times, and are also widely exploited in the contexts of biology and chemistry. We intend to couple a mesoscopic ensemble (106-1012) of electron spins to a superconducting resonator.  While the individual spin coupling is small (g~50 Hz), the collective coupling to an ensemble can be large (geff~10 MHz), allowing fast interactions with superconducting qubits.  Initial experiments have already observed evidence of the spin-resonator coupling in ruby and diamond[7].   Through a collaboration with groups at Oxford and Aarhus, my colleagues and I have adapted techniques from phase-encoded MRI, to show that a single ensemble can efficiently store many qubits[8-9].  The long term goal is to use a superconducting qubit to produce arbitrary single photon states which would then be stored as an excitation in the spin ensemble for later retrieval and observation.   Many embedded electron spins are also optically active, allowing the possibility to create a single-photon microwave to optical upconverter, an important capability if superconducting based quantum information processors are to communicate over long distances.  This system will have uses beyond QIP, as an on-chip quantum limited maser amplifier for example. We also hope to use this quantum-computing-inspired method to explore applications in traditional electron spin resonance (ESR) quantum computing experiments.  The small mode volume (V~10-6 cubic wavelengths) of the transmission line cavity, which substantially increases the coupling strength will allow me to measure small numbers of spins at the single photon level, down to millikelvin temperatures, an interesting regime that has been traditionally difficult to access.