Whereas typical computer systems retailer info within the type of bits, basic items of logic that take a price of both 0 or 1, quantum computer systems are based mostly on qubits. These can have a state that’s concurrently each 0 and 1. This odd property, a quirk of quantum physics referred to as superposition, lies on the coronary heart of quantum computing’s promise to finally resolve issues which might be intractable for classical computer systems.
Many present quantum computer systems are based mostly on superconducting digital programs during which electrons circulate with out resistance at extraordinarily low temperatures. In these programs, the quantum mechanical nature of electrons flowing by way of fastidiously designed resonators creates superconducting qubits. These qubits are wonderful at rapidly performing the logical operations wanted for computing. Nonetheless, storing info — on this case quantum states, mathematical descriptors of specific quantum programs — will not be their robust go well with. Quantum engineers have been looking for a solution to increase the storage instances of quantum states by developing so-called “quantum reminiscences” for superconducting qubits.
Now a workforce of Caltech scientists has used a hybrid strategy for quantum reminiscences, successfully translating electrical info into sound in order that quantum states from superconducting qubits can survive in storage for a interval as much as 30 instances longer than in different methods.
The brand new work, led by Caltech graduate college students Alkim Bozkurt and Omid Golami, supervised by Mohammad Mirhosseini, assistant professor {of electrical} engineering and utilized physics, seems in a paper printed within the journal Nature Physics.
“After getting a quantum state, you won’t wish to do something with it instantly,” Mirhosseini says. “You’ll want to have a solution to come again to it if you do wish to do a logical operation. For that, you want a quantum reminiscence.”
Beforehand, Mirhosseini’s group confirmed that sound, particularly phonons, that are particular person particles of vibration (in the way in which that photons are particular person particles of sunshine) might present a handy methodology for storing quantum info. The gadgets they examined in classical experiments appeared splendid for pairing with superconducting qubits as a result of they labored on the identical extraordinarily excessive gigahertz frequencies (people hear at hertz and kilohertz frequencies which might be no less than 1,000,000 instances slower). Additionally they carried out effectively on the low temperatures wanted to protect quantum states with superconducting qubits and had lengthy lifetimes.
Now Mirhosseini and his colleagues have fabricated a superconducting qubit on a chip and linked it to a tiny machine that scientists name a mechanical oscillator. Basically a miniature tuning fork, the oscillator consists of versatile plates which might be vibrated by sound waves at gigahertz frequencies. When an electrical cost is positioned on these plates, the plates can work together with electrical indicators carrying quantum info. This permits info to be piped into the machine for storage as a “reminiscence” and be piped out, or “remembered,” later.
The researchers fastidiously measured how lengthy it took for the oscillator to lose its precious quantum content material as soon as info entered the machine. “It seems that these oscillators have a lifetime about 30 instances longer than one of the best superconducting qubits on the market,” Mirhosseini says.
This methodology of developing a quantum reminiscence affords a number of benefits over earlier methods. Acoustic waves journey a lot slower than electromagnetic waves, enabling rather more compact gadgets. Furthermore, mechanical vibrations, not like electromagnetic waves, don’t propagate in free house, which signifies that vitality doesn’t leak out of the system. This permits for prolonged storage instances and mitigates undesirable vitality alternate between close by gadgets. These benefits level to the chance that many such tuning forks might be included in a single chip, offering a probably scalable approach of constructing quantum reminiscences.
Mirhosseini says this work has demonstrated the minimal quantity of interplay between electromagnetic and acoustic waves wanted to probe the worth of this hybrid system to be used as a reminiscence ingredient. “For this platform to be really helpful for quantum computing, you want to have the ability to put quantum information within the system and take it out a lot quicker. And that signifies that we have now to seek out methods of accelerating the interplay charge by an element of three to 10 past what our present system is able to,” Mirhosseini says. Fortunately, his group has concepts about how that may be completed.
Extra authors of the paper, “A mechanical quantum reminiscence for microwave photons” are Yue Yu, a former visiting undergraduate pupil within the Mirhosseini lab; and Hao Tian, an Institute for Quantum Data and Matter postdoctoral scholar analysis affiliate in electrical engineering at Caltech. The work was supported by funding from the Air Power Workplace of Scientific Analysis and the Nationwide Science Basis. Bozkurt was supported by an Eddleman Graduate Fellowship.
