Pre-detection squeezing as a resource for high-dimensional Bell-state measurements

TL;DR

This paper proposes a scalable, high-dimensional Bell measurement scheme using multiple squeezer devices in linear optical circuits, eliminating the need for ancillary photons and overcoming previous dimensional limitations.

Contribution

It introduces a novel, resource-efficient method for high-dimensional Bell measurements employing pre-detection squeezing, enhancing scalability and practicality.

Findings

The scheme does not require ancillary photons.

It is scalable to high-dimensional quantum states.

Experimental feasibility is demonstrated.

Abstract

Bell measurements, entailing the projection onto one of the Bell states, play a key role in quantum information and communication, where the outcome of a variety of protocols crucially depends on the success probability of such measurements. Although in the case of qubit systems, Bell measurements can be implemented using only linear optical components, the same result is no longer true for qudits, where at least the use of ancillary photons is required. In order to circumvent this limitation, one possibility is to introduce nonlinear effects. In this work, we adopt the latter approach and propose a scalable Bell measurement scheme for high-dimensional states, exploiting multiple squeezer devices applied to a linear optical circuit for discriminating the different Bell states. Our approach does not require ancillary photons, is not limited by the dimension of the quantum states, and is experimentally scalable, thus paving the way toward the realization of an effective high-dimensional Bell measurement.