Columbia University Team Shrinks Qubits

Capacitors built from 2D materials could lead the way to smaller and more efficient quantum computers.

Researchers at Columbia University have announced new technology that could one day lead to smaller qubits. According to the announcement, qubits need to be on the same wavelength to be effective. “Achieving this, however, has come at the cost of size. Whereas the transistors used in classical computers have been shrunk down to nanometer scales, superconducting qubits these days are still measured in millimeters—one millimeter is one million nanometers.”

The large size of qubits makes it difficult to miniaturize quantum circuits, which could ultimately limit the development of quantum computers. “To shrink qubits down while maintaining their performance, the field needs a new way to build the capacitors that store the energy that “powers” the qubits. In collaboration with Raytheon BBN Technologies, Wang Fong-Jen Professor James Hone’s lab at Columbia Engineering recently demonstrated a superconducting qubit capacitor built with 2D materials, rendering it a fraction of the size of previous capacitors.”

The team used planar capacitors with layers one atom thick that are held together by van der Waals forces. The qubits found the same wavelength when cooled down close to absolute zero. The technique appears promising, but Hone notes that it is still a proof of concept that requires further research. “The coherence time was short—a little over one microsecond, compared to about 10 microseconds for a conventionally built coplanar capacitor, but this is only a first step in exploring the use of 2D materials in this area.”