New quantum acoustic memories can make quantum computers more effective.

 

"Illustration of a silicon-vacancy center in a diamond crystal lattice. Credit: Doug Quade. The same tiny vibrations that carry quantum information across a chip could also keep that information from fading away."  (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

Quantum systems are very problematic tools. They are very sensitive to electromagnetic vibrations. This means. That researchers. Must find new ways to store information in quantum systems. Traditional quantum computers are hybrid systems. The binary computer controls the qubits. In. The quantum processors. And then that information is stored in the binary form. This makes those systems slow. If. The system can store information as qubits. That makes it faster. 

New types of quantum memories can store information as acoustic waves. An acoustic wave is a molecular- or atomic-scale wave. Theoretically, we could also store information directly in sound waves. If. We could freeze those sound waves in their form.

It is possible. To store those sound waves on tape. This acoustic tape means the layer. That is, in the chamber, there is gas. When a sound wave travels over that tape. The system pushes gas very fast against that tape. If. That happens fast enough. 

The pressure system can trap those sound or pressure waves on the layer. And then a laser could read the form of those atoms. 

Today. Researchers are testing phonons as tools. That can protect quantum information. Using tiny sound waves. Sound waves can travel in a diamond carbon structure. That structure. 

You see in the image above. Can turn diamonds into tiny LRAD devices. Those systems can aim sound waves with very high accuracy. And theoretically. If. Researchers could create quantum entanglement through that channel. But. Another possibility is to store information. Into. Acoustic qubits. 

Harvard scientists dressed those qubits using acoustic fields. Or they created dressed states. The system creates superposition between fields. That surround silicon vacancy states. 

“Because the protective field is mechanical, it can operate inside the same phononic cavities intended to connect stationary quantum nodes. Phonons could therefore serve two functions in one device: moving quantum information between qubits and shielding that information while it is stored.” (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

 Eliza Cornell, Ph.D., describes it like that. Researchers solved two problems. Shew says that. 

“We want the spin to have strong interaction with phonons, and we want the spin to have a long coherence time. Our paper demonstrates a method of extending the coherence time that is compatible with the silicon-vacancy center being in a cavity.” (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

“The technique extended the coherence time of the silicon-vacancy spin by roughly threefold, showing that continuous-wave mechanical noise suppression can protect quantum information in a real device. (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

“The researchers also achieved a Rabi frequency of 800 megahertz, enabling exceptionally fast control of the spin. Together, longer coherence and rapid operation could support high-fidelity quantum gates mediated by phonons, bringing compact on-chip quantum networks closer to practical use.” (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

The acoustic qubit can store an acoustic field around it. So those memories are actually phonons. Or they are phonons. Dressed with acoustic fields. 

Interaction directly with phonons is difficult to control. A useful quantum memory must preserve coherence. This means. It must retain its quantum state long enough. It can store, process, and transmit information. Environmental noise can quickly destroy that state.

Noise from the environment. It destroys the qubit. Another big problem is: How to multiply oscillations? Between phonons?  In those systems, oscillations must be precisely multiplied. 

In this case, those phonons can be in direct lines. And some laser or acoustic beam travels over them. And. That makes it possible to multiply those oscillations over those fields. The system must put those qubits in line. And then. Press. A quantum channel that allows them to transmit information directly between those qubits. 

“A dressed qubit is described as “wearing” the continuous acoustic field surrounding it. This changes how the qubit responds to its environment, making it less vulnerable to low-frequency noise that would otherwise disrupt its stored information.” (ScitechDaily, Harvard Scientists Use Tiny Sound Waves To Protect Quantum Information)

When. Information is stored in acoustic form. Into silicon vacancy centers in those diamonds. In the most exciting model, those vacancy centers could be in the nanodiamonds. Those diamonds can form quantum channels in the quantum chip. 

So, as is said in this text. 

Silicon vacancy centers could store acoustic information. This technology allows researchers to build new types of quantum information storage. In that solution, the diamond’s carbon structure prevents those vacancy centers from delivering the wave motion. 

When those vacancy centers get a signal. Silicon vacancy centers start to deliver the wave motion. They stored. During this process, silicon vacancy centers store acoustic waves in their structure. And then they deliver that wave motion when they get an impulse that triggers the information delivery. This type of mass memory can be a new way to store information in quantum systems. 

They stored. Those diamonds can also be used. To create pressure. That makes wires superconducting. This is one way to create new, smaller quantum computers. And maybe someday. Those tools. They can turn into desktop models. 

https://scitechdaily.com/harvard-scientists-use-tiny-sound-waves-to-protect-quantum-information/