Establishing spin-network topologies by repeated projective measurements

TL;DR

This paper demonstrates how repeated projective measurements induce relaxation-like dynamics in N-spin coupled networks, enabling the establishment of specific spin-network topologies in liquid-state NMR experiments.

Contribution

It introduces a novel method to control spin-network topologies using quantum Zeno effects through repeated projective measurements.

Findings

Experimental implementation of topology control in NMR

Determination of coupling constants in complex networks

Observation of relaxation-like polarization transfer behaviors

Abstract

It has been recently shown that in quantum systems, the complex time evolution typical of many-bodied coupled networks can be transformed into a simple, relaxation-like dynamics, by relying on periodic dephasings of the off-diagonal density matrix elements. This represents a case of "quantum Zeno effects", where unitary evolutions are inhibited by projective measurements. We present here a novel exploitation of these effects, by showing that a relaxation-like behaviour is endowed to the polarization transfers occurring within a N-spin coupled network. Experimental implementations and coupling constant determinations for complex spin-coupling topologies, are thus demonstrated within the field of liquid-state nuclear magnetic resonance (NMR).