Entangling quantum gate in trapped ions via Rydberg blockade

TL;DR

This paper proposes a theoretical method to implement entangling quantum gates between trapped ions using Rydberg states, overcoming vibrational mode coupling issues by employing dressed states with long-range dipolar interactions.

Contribution

It introduces a novel approach using microwave-dressed Rydberg states to achieve vibrational mode-independent entangling gates in trapped ions.

Findings

Dressed states mitigate vibrational coupling effects.

Long-range dipolar interactions enable controlled phase gates.

The method offers a pathway for scalable ion-based quantum computing.

Abstract

We present a theoretical analysis of the implementation of an entangling quantum gate between two trapped Ca$^+$ ions which is based on the dipolar interaction among ionic Rydberg states. In trapped ions the Rydberg excitation dynamics is usually strongly affected by mechanical forces due to the strong couplings between electronic and vibrational degrees of freedom in inhomogeneous electric fields. We demonstrate that this harmful effect can be overcome by using dressed states that emerge from the microwave coupling of nearby Rydberg states. At the same time these dressed states exhibit long range dipolar interactions which we use to implement a controlled adiabatic phase gate. Our study highlights a route towards a trapped ion quantum processor in which quantum gates are realized independently of the vibrational modes.