Controlling and exploiting phases in multi-spin systems using electron spin resonance and nuclear magnetic resonance

Abstract

The phase of a superposition state is a quintessential characteristic that differentiates a quantum bit of information from a classical one. This phase can be manipulated dynamically or geometrically, and can be exploited to sensitively estimate Hamiltonian parameters, perform faithful quantum state tomography and encode quantum information into multiple modes of an ensemble. Here we discuss the methods that we have employed to manipulate and exploit the phase information of single-, two-, multi-qubit and multi-mode spin systems.

Spin Quantum Computing with Endohedral Fullerenes

“…Morton et al have shown 48,92 that in the coupled spin system the electron can be used as an auxiliary resource to dramatically speed up nuclear spin manipulation. 95 In essence, driving an electron spin transition connected to the nuclear spin can create arbitrary changes of the nuclear phase with high precision, but at the time scale of the electron spin Rabi frequency ('bang-bang' pulse duration ~100 ns, see Fig. 4).…”

Nuclear magnetic resonance quantum information processing

“…Such a topic is reviewed by Schulte-Herbrüggen et al [4], which illustrates the techniques of quantum control in mixed-state scenarios considering some algorithm classes, such as characterizing the Jones polynomial in order to distinguish between different knots. The quantum control of phases is also the main topic exploited in Simmons et al [5].…”