M.Sc Thesis

M.Sc StudentArtzi Yaron
SubjectAdvances in High Sensitivity and High Spatial Resolution
Electron Spin Resonance towards Implementation
of Quantum Gate Operations
DepartmentDepartment of Physics
Supervisors PROFESSOR EMERITUS Joseph Avron
PROF. Aharon Blank
Full Thesis textFull thesis text - English Version


Quantum information theory predicts a major speedup in several important computational processing tasks, which makes it a subject of great interest. However, the search for a physical system in which such quantum information processing algorithms can be successfully executed is still underway. One possible implementation of a quantum information processing unit may be achieved by directly addressing electron spins in a solid-state sample, using methods of induction-detection pulsed electron spin resonance (ESR).

En-route towards experimental implementation of quantum logic gates (unitary operations) on electron spin states, employing methods of pulsed ESR, the detection sensitivity that is available in state-of-the-art ESR systems has to be improved significantly. Accordingly, the first aim of this thesis is to develop and test a new experimental setup that pushes the available spin sensitivity by more than an order of magnitude, compared to the previous state-of-the-art laboratory-based systems. We present experimental results that were recorded in our ultra-sensitive induction-detection ESR setup, with a sample of Phosphorus doped isotopically pure Silicon crystal, showing such an improvement in detection sensitivity. We estimate that the number of electron spins required for a detectable signal in that setup is only ~10000 spins, which is 5 orders of magnitude lower

than in the most sensitive commercial ESR setup. This high sensitivity was achieved thanks to the development of an ultra-miniature micrometer-sized microwave resonator that was operated at 34 GHz at cryogenic temperatures in conjunction with a unique cryogenically cooled low noise amplifier.

Moreover, for the implementation of a quantum computer in a solid-state sample, using methods of induction-detection pulsed ESR, another crucial need is to have the ability to selectively address some of the electron spins in the sample and operate with quantum logic gates on them, without influencing other spins nearby. As a first step towards developing such an ability, we characterize the capabilities of our induction-detection ESR setup for spatially selective addressing of electron spins in a solid-state sample, by employing strong magnetic field gradients that are available in our unique setup. We present experimental results that demonstrate the extent of our selective addressing abilities and estimate that, currently, at most we can selectively address electron spins in a slice of ~300 [nm] in width.