Quantum Computing With Mothballs: Scientists Find A Way To Stabilize Electron Spins At Room Temperature

An international team of researchers has, in a paper published Monday in the journal Nature Communications, reported a breakthrough that may open the door to the construction of viable quantum computers. The key to the future of quantum computing could be naphthalene — the active ingredient in mothballs.

Quantum computers utilize two basic properties these qubits possess — superposition and entanglement. Unlike conventional bits, which can exist in one of the two states, 0 and 1, qubits can exist in superposition, allowing them to have both states at the same time. This superposition of qubits, coupled with quantum entanglement — wherein they are physically separate but act as if they are connected — is what gives quantum computers a significant advantage over conventional computers.

The development of quantum computers capable of performing operations many orders of magnitude faster than conventional computers has been a goal of computer scientists and physicists ever since the idea was first floated in the early 1980s. However, for a viable quantum computer to be built, electron spin — an intrinsic property of electrons that can be used as a qubit — needs to be stabilized so that that the spin lifetime exceeds at least 100 nanoseconds.

Until now, the only way scientists have been able to achieve this is by cooling a material to near absolute zero (-273 degrees Celsius or -459.4 degrees Fahrenheit).

“We have demonstrated that a long conduction electron spin lifetime in metallic-like material made up of carbon nanospheres can be achieved at room temperature. This material was produced simply by burning naphthalene, the active ingredient in mothballs,” Mohammad Choucair from the University of Sydney, who co-led the research, wrote in an article published in the Conversation. “This allowed us to achieve a new record electron spin lifetime of 175 nanoseconds at room temperature.”

According to the researchers, the new material — which has a nano-sized spherical and disordered structure — not only solves the problem of temperature in quantum computing, it also has the conductivity needed to integrate it into existing silicon technologies.

“Our work now opens the possibility for spin qubits to be manipulated in a conducting material at room temperature. This method doesn’t need any isotopic engineering of a host material, dilution of the spin-carrying molecule, or cryogenic temperatures,” Choucair wrote for the Conversation. “It allows a higher density packing of qubits to be, in principle, achieved over other promising qubits like those used in silicon.”