Quantum Data Compression of a Qubit Ensemble

TL;DR

This paper introduces a quantum data compression protocol that can theoretically perfectly compress qubit ensembles into exponentially fewer qubits, and demonstrates its experimental implementation with photonic qubits.

Contribution

The paper presents a novel quantum compression protocol and experimentally compresses three photonic qubits into two, highlighting potential for more efficient quantum memory storage.

Findings

Perfect compression of qubit ensembles is theoretically possible.

Experimental demonstration of compressing three qubits into two.

Quantum compression differs fundamentally from classical data compression.

Abstract

Data compression is a ubiquitous aspect of modern information technology, and the advent of quantum information raises the question of what types of compression are feasible for quantum data, where it is especially relevant given the extreme difficulty involved in creating reliable quantum memories. We present a protocol in which an ensemble of quantum bits (qubits) can in principle be perfectly compressed into exponentially fewer qubits. We then experimentally implement our algorithm, compressing three photonic qubits into two. This protocol sheds light on the subtle differences between quantum and classical information. Furthermore, since data compression stores all of the available information about the quantum state in fewer physical qubits, it could provide a vast reduction in the amount of quantum memory required to store a quantum ensemble, making even today's limited quantum memories far more powerful than previously recognized.