Security enhanced memory for quantum state

TL;DR

This paper demonstrates a quantum memory with an encryption function using phase scrambling and retrieval, enhancing security in quantum information storage.

Contribution

The authors experimentally implement a quantum memory with an encryption mechanism based on phase scrambling and retrieval, a novel approach in quantum security.

Findings

Successfully scrambled and retrieved quantum phase using Ramsey interferometers.

Demonstrated phase encryption enhances security of quantum memory.

Operated two independent interferometers with random phases for encryption.

Abstract

Security enhancement is important in terms of both classical and quantum information. The recent development of a quantum storage device is noteworthy, and a coherence time of one second or longer has been demonstrated. On the other hand, although the encryption of a quantum bit or quantum memory has been proposed theoretically, no experiment has yet been carried out. Here we report the demonstration of a quantum memory with an encryption function that is realized by scrambling and retrieving the recorded quantum phase. We developed two independent Ramsey interferometers on an atomic ensemble trapped below a persistent supercurrent atom chip. By operating the two interferometers with random phases, the quantum phase recorded by a pulse of the first interferometer was modulated by the second interferometer pulse. The scrambled quantum phase was restored by employing another pulse of the second interferometer with a specific time delay. This technique paves way for improving the security of quantum information technology.