Quantum physics is gaining more and more popularity around the world.
We often read in the news about many advancements involving quantum technologies, and how this branch of physics is transforming things we used to come across only in sci-fi books into surprising realities.
Yet, the quantum theory was invented more than a century ago.
Before the 1900, physicists had been haunted by one particular problem in spite of their certainty that everything that was needed to be known in the field of physics had been already attained.
It concerned a thing they called ‘black body’, which is a theoretical physical body which with the capacity to absorb all incident electromagnetic radiation whatever the frequency or angle of incidence.
None of the physicists could solve the mystery of black body radiation.
Then, in December 1900, Max Karl Ernst Ludwig Planck, a German theoretical physicist, succeeded in resolving the mystery about black body radiation. Planck created an equation which showed that energy is emitted in discrete packets, which he called “quanta.”
This led to his winning the Nobel Prize for Physics in 1918.
Since then, the quantum theory has been applied in many things like lasers, compact discs, DVDs, digital cameras, bar-code readers, photocopying machines, solar cells, fiber-optics, LED lights, transistors, computer screens, semi-conductors, spectroscopy, and magnetic resonance imaging scanners.
Nowadays, quantum mechanics is seeing an even wider range of applications. People are processing and transmitting voluminous data which are in urgent need of high-level security. In addition to this, convenient and ultra-functional memory storage are very much in-demand.
Quantum cryptography is proving to be a very useful technique in transmitting information with the use of entangled photons or light particles.
But since light is very sensitive, storing quantum information presents a very difficult challenge.
This great challenge has been met by a group of scientists from Caltech, the National Institute of Standards and Technology, and the University of Verona, Italy. The research team has developed a nanocavity memory device, which can store vast information at a size 1000x smaller than current macroscopic memory storage systems.
The new memory device can even easily fit into a chip!
Photonic information is best stored in a crystal. You only have to couple a crystal’s natural resonance to the frequency of the light particles for storage.
In their study, the scientists created a nano-sized cavity which contained rare-earth neodymium atoms that are very effective in trapping light. These atoms were themselves trapped in a yttrium orthovanadate (YVO) crystal which improved interactions between light and the rare-earth metal at the level of single photons. The technique resulted to increased efficiency of the storage system and the spin polarization where the quantum bits were.
As the authors stated on Science, “We demonstrate a high-fidelity nanophotonic quantum memory based on a mesoscopic neodymium ensemble coupled to a photonic crystal cavity. The nanocavity enables >95% spin polarization for efficient initialization of the atomic frequency comb memory. And time-bin-selective readout via enhanced optical Stark shift of the comb frequencies. Our solid-state memory is integrable with other chip-scale photon source and detector device for multiplexed quantum and classical information processing at the network nodes.”
With this nanocavity design, implementing a quantum internet would be easier since it provides a clear idea on how to produce effective medium- to- large scale quantum memories.
The next challenge now facing the research team is how to facilitate commercial production of their model memory device. Its current fabrication process, which involves ion beam milling, takes time. This has to be sped up, and they also intend to further improve the memory efficiency and storage time of this new quantum invention, which if achieved, will obviously make its functionality even more appealing.