The strange particle that holds the key to ‘quantum supercomputer

Source: The post is based on the article “The strange particle that holds the key to quantum supercomputer” published in “The Hindu” on 11th July 2023.

Syllabus: GS 3 – science and technology (awareness in the fields of computer)

News: Researchers from Microsoft reported engineering a topological superconductor made of an aluminum superconductor and an indium arsenide semiconductor.

What does the term ‘Majorana’ mean?

‘Majorana’ refers to fermions that are their own antiparticles, as proposed by the Italian physicist Ettore Majorana in 1937. These particles satisfy certain conditions under the Dirac equation, originally developed by the British physicist Paul Dirac in 1928 to incorporate quantum mechanics with special relativity. The equation predicts that each particle has a corresponding antiparticle, and Majorana discovered that certain particles could serve as their own antiparticles.

What is Majorana Zero Mode?

Majorana zero modes are a unique kind of particle, a bound state of fermions that are their own antiparticles. These particles have distinct quantum numbers, including quantum spin with half-integer values, such as 1/2, 3/2, 5/2, and so on. The rules applicable to single fermions also apply to these bound pairs. If these bound states encounter each other, they annihilate, justifying their title as Majorana fermions.

What are the benefits of  Majorana Zero Mode for Quantum Computing?

Majorana zero modes offer significant benefits to quantum computing. They act as stable qubits, with the unique ability to exist in two states simultaneously, providing a basis for quantum superposition. By encoding information into these modes, quantum computers can be shielded from decoherence, a typical challenge with these machines. Additionally, these zero modes employ non-Abelian statistics, offering an extra degree of freedom and potentially different outcomes, depending on the order of operations. Consequently, Majorana zero modes could unlock superior quantum computing capabilities, from increased resilience to expanded computational possibilities.

What does ‘Topological’ mean?

“Topological” refers to properties of a system that remain unchanged even when the system is continuously deformed, such as stretching or twisting, without tearing or gluing. Topological degeneracy is a state in quantum mechanics where multiple configurations can exist at the system’s lowest energy. In context of quantum computing, Majorana zero modes can store information across different topological properties and, due to this topological nature, they are more robust to disturbances, making them ideal candidates for qubits in quantum computing.

What are the challenges in realizing Majorana Zero Modes?

First, isolating Majorana zero modes experimentally is extremely challenging due to the precise conditions required. They are expected to exist only in certain types of superconductors, under very specific conditions.

Second, even if isolated, verifying their existence is difficult. Majorana zero modes leave a minimal experimental footprint, making their detection and confirmation problematic.

Third, there’s a challenge in maintaining the stability of Majorana zero modes. The stability of these states is extremely sensitive to environmental influences, which could easily disrupt them.

Fourth, the manipulation of Majorana zero modes is not straightforward. It requires highly advanced and controlled experimental techniques, which are currently not fully developed.

Lastly, scaling up from individual Majorana zero modes to a fully functional quantum computer architecture is a monumental task, involving numerous technical and conceptual obstacles.

What new discovery has Microsoft made?

Researchers at Microsoft have reported the engineering of a topological superconductor from an aluminium superconductor and an indium arsenide semiconductor. They claim that their device passed the “topological gap protocol,” which suggests a high probability of hosting Majorana zero modes. Microsoft’s VP of advanced quantum development stated that the company believes that a quantum supercomputer using these qubits could be built within 10 years and could perform a reliable one million quantum operations per second. Despite this, many experts remain cautious and believe that independent confirmation of the results is required, and that topological quantum computing could still be at least a century away.