To live up to the hype, quantum computers must repair their error problems. (Image credit- Science News)
Performance-Enhanced Array for Counting Optical Quanta (PEACOQ), a quantum detector created by NASA’s Jet Propulsion Laboratory (JPL) and Caltech, can measure individual photons of light with an accuracy of 100 trillionths of a second at a pace of 1.5 billion photons per second.
With the help of a specialised quantum communications network, this achievement might pave the way for extensive quantum data sharing between quantum computers distributed over very long distances.
Unlike traditional computers, which transmit data as a succession of 1s and 0s, quantum computers encode information using quantum bits (qubits).
Qubits are fundamental particles that can never be replicated or transferred again without being destroyed, like electrons and photons. The size of any prospective network is also constrained by the rate at which information deteriorates when conveyed by encoded photons over optical fibres.
To get around these limitations, a dedicated free-space optical quantum network might have space nodes on board satellites orbiting the Earth.
By creating entangled photon pairs and transmitting them to two quantum computer terminals hundreds or thousands of kilometres distant, these nodes would serve as data relays.
To precisely pinpoint the instant it receives each photon and transmit the data it contains, a particularly sensitive detector is needed, such as PEACOQ.
32 niobium nitride superconducting nanowires on a silicon chip make up the tiny detector PEACOQ, which has a dimension of just 13 microns. According to NASA, a nanowire is 10,000 times thinner than a human hair.
It takes a cryogenic temperature of minus 458 degrees Fahrenheit (minus 272 degrees Celsius) to keep the nanowires in the detector in their superconducting state, which is just one degree above absolute zero.
To transform absorbed photons into electrical pulses that communicate the quantum information, they must be in this state. PEACOQ was built on the detector designed for NASA’s Deep Space Optical Communications (DSOC) technology demonstration.
The DSOC ground station at Caltech’s Palomar Observatory in Southern California requires the same high sensitivity to counting individual photons as they come in by laser from the DSOC transceiver as it travels through deep space, even though DSOC won’t carry quantum information.
The study’s lead author, Ioana Craiciu, a postdoctoral researcher at JPL, said in a statement that PEACOQ will soon be employed in laboratory studies to show quantum communications at faster rates or over wider distances. In the long run, it might offer a solution to the problem of how to send quantum data across the globe.
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PEACOQ was created by JPL’s Microdevices Laboratory with funding from NASA’s Space Communications and Navigation programme as a component of a wider NASA attempt to offer free-space optical communications between space and the ground.