20 June 2012, 5 pm
'Single Atom Spin Qubits in Silicon’
Frank Lecture Theatre
Quantum information technologies promise to revolutionize the way information is transmitted and processed. These transformational technologies require devices that enable the sensing and manipulation of individual electrons and photons. ANFF-NSW has established a combination of high-resolution electron-beam lithography, silicon MOS device engineering, and specialized nanofabrication facilities that are custom-designed for quantum technology research. We support a number of world-leading research efforts in developing semiconductor qubit devices for quantum computing. This talk will highlight recent work on the development of silicon-based qubits.
Electron spin qubits in silicon are excellent candidates for scalable quantum information processing due to the very long spin lifetimes (T1) and coherence times (T2) that are accessible in silicon and because of the enormous investment to date in silicon MOS technology. This talk will discuss spin qubits in which the electron spin is localized on single Phosphorus donor atom in silicon, first envisaged by Kane in 1998 .
Projective readout of the qubit is an essential criterion for any quantum computing system. Due to the challenges of controlling and manipulating single spins in silicon, it is only very recently that single-shot readout of an electron spin has been demonstrated. This experiment  used a device consisting of implanted phosphorus donors, tunnel-coupled to a silicon Single Electron Transistor (Si-SET) , where the SET island was used as a reservoir for spin-to-charge conversion.
Single spin read-out has been a long sought-after goal in silicon and the work has shown that spin lifetimes (T1) can be as long as 6 seconds at the cryogenic qubit operation temperatures. These timescales are very long compared with qubit gate operation times. The qubit readout was also demonstrated with high fidelity (> 90%), another critical requirement for scalable quantum computing.
Finally, the talk will report demonstration of both electron spin qubit and nuclear spin qubit control using on-chip microwave transmission lines, enabling single-atom electron spin resonance (ESR) and nuclear magnetic resonance (NMR). Together with single-shot spin readout, these results open the pathway to the development of quantum information processing in silicon.
H H Wills Physics Laboratory.
All are welcome.
The Physics Colloquia are organised byand Rachel Bishop.
Please contact Rachel Bishop for further information.