The transducer could allow quantum networks superconductive

Applied physicists from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have created a photon router that could connect to quantum networks to create robust optical interfaces for quantum microwave-sensitive computers.

The breakthrough is a crucial step towards a day making modular and distributed quantum computer networks which take advantage of the existing telecommunications infrastructure. Including millions of kilometers of optical fibers, today’s optical fiber networks send information between computer clusters in the form of light impulses, or photons, around the world in the blink of an eye.

Directed by Marko Lončar, Professor of Electric Engineering Tiesai Lin and physics applied to the sea, the team has created an optical microwave transducer, a device designed for quantum treatment systems that use superconductive microwaves like their smallest operating units (analogues at 1 and 0 of conventional bits).

Research is published in Nature physics.

Indeed, a router for photons, the transducer fills the big energy difference between microwaves and optical photons, thus allowing the control of microwave qubits with optical signals generated several kilometers. The device is the first of its kind to demonstrate the control of a superconductive qubit using only light.

Hana Warner, a student with the first author and paper graduate, said that the transducer offers a means of supporting the power of the optics when creating quantum networks.

“The realization of these systems is always a way to go out, but to get there, we must find practical ways of scale and interface with the different components,” said Warner.

“Optical photons are one of the best ways to do so, because they are very good information carriers, with a low loss and a high bandwidth.”

Supervisive qubits, which are nanofabrified circuits designed for different energy states, are an emerging quantum calculation platform due to their scalability, their compatibility with existing manufacturing processes and the capacity to maintain quantum overlapping long enough to carry out calculations.

But one of the main bottlenecks to deploy platforms of superconductive microwaves is the extremely low temperatures to which they must operate, requiring large cooling systems called dilution refrigerators.

Since the future quantum computer will require millions of qubits to operate, the scaling of these systems only on microwave frequency signals is difficult. The solution lies in the use of microwave qubits to carry out quantum operations, but to use optical photons as effective and scalable interfaces.

This is where the transducer comes into play.

The 2 millimeter optical device from the Harvard team looks like a trombone and is on a chip that measures approximately 2 centimeters. It works by connecting a microwave resonator with two optical resonators, allowing an exchange of back and forth of energy activated by the properties of their basic material, the lithium niobate. The team has exploited this exchange to eliminate the need for hot and voluminous microwave cables to control the qubit states.

The same devices used for control can be used for reading the QUBIT state, or to train direct links to convert capricious quantum information into robust packets of light between quantum computer nodes. The breakthrough brings us closer to a world with quantum processors, which are superconducting connected by optical networks at a loss with low loss and high power.

“The next stage of our transducer could be a reliable generation and distribution of the tangle between microwave qubits using light,” said Lončar.

The Harvard team has combined its expertise in optical systems with Rigetti Computing collaborators, which provided the aluminum suppacts on silicon suppactive qubit on which the researchers tested their different experiences. Other employees were from the University of Chicago and the Massachusetts Institute of Technology.

The manufacture of fleas was carried out at the Harvard’s Center for Nanoscale Systems, a member of the coordinated infrastructure network of national nanotechnology.