Super-activating quantum memory by entanglement-breaking channels

TL;DR

This paper demonstrates that combining two entanglement-breaking channels in a specific way can enable quantum memory capabilities that are impossible for individual channels, revealing a super-activation phenomenon.

Contribution

It introduces the concept of super-activation of quantum memory using entanglement-breaking channels, showing their combined potential exceeds individual limitations.

Findings

Two entanglement-breaking channels can be super-activated for quantum memory.

Super-activation enables entanglement preservation where single channels cannot.

The work reveals new possibilities for quantum memory using channel combinations.

Abstract

Entanglement is an essential resource for various quantum-information tasks. When a target system shares entanglement with another memory system and is stored reliably, one can use entanglement at a later time -- this is quantum memory. In practice, entanglement can be exceedingly fragile during a system's evolution. In particular, no entanglement can survive when a so-called entanglement-breaking channel acts on the target system. Are entanglement-breaking channels really useless for maintaining entanglement? As a single channel, this is certainly the case; it cannot be useful for quantum memory. However, in this work, we show that putting together two entanglement-breaking channels in a broadcasting scenario can activate their ability to maintain entanglement -- the channel's quantum memory resource can be super-activated.