At its recent I/O 2021 summit, Google unveiled its ambitious quantum computing project, which it claims to be ‘useful’ and ‘error-free’. The error-corrected quantum computer(QC) at its quantum AI, Santa Barbara campus, will be ready in 2029, according to the company. A typical quantum computing job would require one to deal with maintaining precise fabrications, supercool temperature to operate, myriad probabilities, frequent errors and more.
Now, a group of MIT researchers involving: Pablo Jarillo-Herrero, Cecil and Ida Green, Professor of Physics at MIT, claim to have found a way to build better QCs. The researchers devised three new quantum electronic devices from a ‘magic material’.
What’s this ‘magic material’
Andre Geim and Konstantin Novoselov from the University of Manchester, UK, received the 2010 Nobel Prize in Physics for experiments regarding the two-dimensional material known by the name Graphene— the magic material. Graphene is a one-atom-thick layer of carbon arranged in a honeycomb structure. Similarly, multiple other applications can be carved out of the same.
Previously, the Jarillo-Herrero group took two layers of Graphene, one placed on top of the other with a tilt of 1.1 degrees. The structure allows Graphene to act both as a superconductor and an insulator, depending on the number of electrons in the system as provided by an electric field.
In the latest experiment, unlike traditional single electrode usage, multiple electrodes were used to provide different voltage to different areas of the Graphene. This led to the material showing other electronic states from superconducting, insulating to somewhere in between at different sections. Utilising this unique property, researchers developed devices for the quantum electronics industry.
The three devices: Josephson junction, or superconducting switch; a spectroscopic tunnelling device; and a single-electron transistor, were created from a single material.
A Josephson junction is created by sandwiching a non-superconducting layer between two superconducting layers. It has its applications in making SQUIDs (superconducting quantum interference devices) make precise measurements of the magnetic fields. The spectroscopic tunnelling device, thus created, will be the key to study more about superconductivity. It holds wide applications such as superconducting wire, which has the potential to carry immense electrical currents without heating to generate large magnetic fields. Similarly, the single-electron transistor device, being extremely sensitive to electric fields, has a variety of applications, including infrared signals detection at room temperature.
The use of a single electrically adjustable material benefits all three devices. Those manufactured using traditional methods and a variety of materials face a number of difficulties. “Now, if you’re dealing with one single material, those problems disappear,” says Daniel Rodan Legrain, lead author of the Nature Nanotechnology paper.
Future direction
Quantum computing holds great potential uses for the future, including the cybersecurity domain. The National Institute of Standards and Technology (NIST), US, is soon going to announce the results for its Post-Quantum Cryptography Standardization project, aimed at cryptographic algorithms for protecting electronic information.
Modelling a simple penicillin molecule would necessitate an absurdly massive classical computer with 10^86 bits, according to Boston Consulting Group. That same process, on modern quantum computers, might be a breeze – and can even lead to the discovery of novel treatments for critical diseases like cancer, Alzheimer’s, and heart diseases. Similarly, other applications include fighting climate change, better AI, traffic optimisation and many more.
Quantum computing holds potential to accelerate the way we deal with problems, but building reliable QCs is the real challenge. Currently, the superconductors operate at extremely low temperatures, thereby limiting their applications. However, the researchers are hopeful that it will create the possibility for high-temperature superconductors in the future.
