# Squeezing as an irreducible resource

**Authors:** Samuel L. Braunstein  
**arXiv:** [quant-ph/9904002](https://arxiv.org/abs/quant-ph/9904002)  
**Date:** 1999-04-01  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/quant-ph--9904002v2/

## Key points

- Study by Samuel L. Braunstein on squeezing in quantum optics
- Optical circuits decomposed into linear multiport interferometer, single mode squeezers, and another multiport interferometer
- No-go theorem on creating superpositions involving macroscopically distinct states through single-photon detection
- Exploration of schemes for generating randomly polarized entangled states and their equivalence within the quantum realm
- Derivation of minimal quantum optical circuits for ideal quantum non-demolition coupling of quadrature-phase amplitudes

## Summary

The study "Squeezing as an Irreducible Resource" by Samuel L. Braunstein delves into the concept of squeezing in quantum optics and its essential role as an unalterable element. Through a comprehensive analysis of optical circuits with linear input-output relationships, the research demonstrates how they can be effectively decomposed into a sequence comprising a linear multiport interferometer, single mode squeezers arranged in a unique manner, and another multiport interferometer. This decomposition strategy leads to the establishment of a significant no-go theorem regarding the creation of superpositions involving macroscopically distinct states through single-photon detection. The study also explores various schemes for generating randomly polarized entangled states and showcases their equivalence within the quantum realm. Additionally, it highlights the derivation of minimal quantum optical circuits designed for achieving ideal quantum non-demolition coupling of quadrature-phase amplitudes. Through elucidating these intricate processes and phenomena within quantum optics, this work contributes valuable insights into the fundamental principles governing squeezing as an indispensable resource in quantum information processing and communication systems.