Zeno and anti-Zeno polarization control of spin-ensembles by induced dephasing

TL;DR

This paper demonstrates how induced dephasing in NMR can control the polarization of spin-ensembles, steering them towards desired purity states through Zeno and anti-Zeno effects.

Contribution

It introduces a method to manipulate qubit ensemble purity using controlled dephasing, combining experimental and theoretical insights into Zeno and anti-Zeno regimes.

Findings

Anti-Zeno regime leads to ensemble purification.

Zeno regime results in ensemble mixing.

Controlled dephasing steers ensemble towards quasi-equilibrium state.

Abstract

We experimentally and theoretically demonstrate the purity (polarization) control of qubits entangled with multiple spins, using induced dephasing in nuclear magnetic resonance (NMR) setups to simulate repeated quantum measurements. We show that one may steer the qubit ensemble towards a quasi-equilibrium state of certain purity, by choosing suitable time intervals between dephasing operations. These results demonstrate that repeated dephasing at intervals associated with the anti-Zeno regime lead to ensemble purification, whereas those associated with the Zeno regime lead to ensemble mixing.