Preface

Abstract

Pulsed nuclear magnetic resonance (NMR) was discovered in 1950 by Erwin L. Hahn.In 62 years of use, the technique has definitely been established as one of the main tools of investigation in physics, chemistry, biology and medicine.Since 1950, NMR has yielded four Nobel Prizes: one in physics (F.Bloch and E. M. Purcell, in 1952), two in chemistry (R. R. Ernst, in 1991 and K. Wüthrich, in 2002) and one in medicine (P.C. Lauterbur and P. M. Mansfield, in 2003).Before the 'pulsed-era', Otto Stern and Isidor Rabi also won the Prize with NMR, in 1943 and 1944, respectively.From the year 1997, pulsed NMR met a novel and exciting area of investigation: quantum information processing (QIP).Nuclear spins are qubits, and radiofrequency pulses are unitary transformations.Add to this some nonunitary operations, such as averages, and voila: spin thermal states in samples at room temperature can behave like pure quantum states, allowing complete quantum algorithms and protocols to be implemented in small molecular quantum computers.For the past 15 years, over 500 papers have appeared in the literature of NMR-QIP and has led to a huge amount of original results, in essentially every single area of research within quantum information and quantum computation: quantum algorithm implementation, quantum communication protocols, simulation of quantum systems (optical systems, condensed matter, Bose-Einstein condensates, harmonic oscillators, etc.), quantum error correction codes, tests of Bell-like inequality violations, tools to characterize and quantify entanglement, studies of decoherence of quantum states in open systems and so on.New NMR tools have been developed, such as strong modulating pulse and gradient ascent pulse engineering techniques for radiofrequency pulse engineering, and sophisticated experiments have been published using these techniques.No other quantum information technique has contributed so much to the area.Such a stimulating activity has resulted in the proposal of the present issue, which gathers many of the experts in the field of NMR-QIP around the world.It has contributions from groups from 10 countries: Argentina, Brazil, Canada, China, UK, Germany, Japan, Russia, Singapore and USA.They describe the state-of-the-art of NMR-QIP, adding various novelties to it.During the organization, it has been a most rewarding experience to interact with these colleagues, and we thank them all for their participation in the project.We are sure that this issue will greatly increase cooperation among groups, and encourage students to enter this promising area, resulting in a healthy feedback to NMR-QIP development.