Deterministic protocol for mapping a qubit to coherent state superpositions in a cavity

TL;DR

This paper presents a deterministic quantum gate that maps a qubit state onto a superposition of two coherent states in a cavity, enabling efficient generation of complex quantum states for quantum information processing.

Contribution

A new gate, called qcMAP, is introduced that transfers arbitrary qubit states into superpositions of coherent states using dispersive qubit-cavity interactions.

Findings

Enables generation of multi-component superpositions of coherent states

Facilitates creation of entangled states of two resonators

Allows construction of multi-qubit GHZ states

Abstract

We introduce a new gate that transfers an arbitrary state of a qubit into a superposition of two quasi-orthogonal coherent states of a cavity mode, with opposite phases. This qcMAP gate is based on conditional qubit and cavity operations exploiting the energy level dispersive shifts, in the regime where they are much stronger than the cavity and qubit linewidths. The generation of multi-component superpositions of quasi-orthogonal coherent states, non-local entangled states of two resonators and multi-qubit GHZ states can be efficiently achieved by this gate.