# Entangling continuous variables with a qubit array

## TL;DR

This paper demonstrates how a qubit array in a waveguide can generate entangled microwave photon pairs with continuous variables, revealing potential for quantum information processing.

## Contribution

It introduces a method for entangling continuous variables using a qubit array emitting photon pairs via collective excitations decay.

## Key findings

- Photon pairs exhibit EPR-like correlations
- Maximum beam intensity scales with number of emitters
- Decay rates and Rabi oscillations are quantitatively analyzed

## Abstract

We show that an array of qubits embedded in a waveguide can emit entangled pairs of microwave photon beams. The quadratures obtained from a homodyne detection of these outputs beams form a pair of correlated continuous variables similarly to the EPR experiment. The photon pairs are produced by the decay of plasmon-like collective excitations in the qubit array. The maximum intensity of the resulting beams is only bounded by the number of emitters. We calculate the excitation decay rate both into a continuum of photon state and into a one-mode cavity. We also determine the frequency of Rabi-like oscillations resulting from a detuning.