What link the 2016 Nobel Prize for physics and electronics ?


Work done in the 1970s and 80s by the three physics Nobel Laureates named earlier this week: David Thouless, Duncan Haldane and Michael Kosterlitz, is just starting to bear fruit in the world of electronics.

The prize, split 50, 25, 25% respectively, was awarded “for theoretical discoveries of topological phase transitions and topological phases of matter”, said the Nobel organization.

Their original analysis was begun to explain some observed properties of matter, including the ‘quantum Hall effect’.

It succeeded, and from it emerged previously un-predicted properties of matter that are only just being proved experimentally.

The first link with electronics is that semiconductors allow topological states to be created.

“Many of the experimental systems used to study topological phase transitions are hetero structures in semiconductors like gallium arsenide which can form two-dimensional electron gas at the layer boundaries,” University of Leeds theoretical physicist Dr Zlatko Papic explained to Electronics Weekly. “If you put this into a magnetic field, it can allow the electrons to form exotic quantum states – to become topological quantum matter.”

And electronics could benefit from the findings.

One class of materials that could one day perform a useful function are ‘topological insulators’, said fellow Leeds physicist Dr Oscar Cespedes. These are insulating solids whose surface has good conductivity. “One surface may conduct relativistic electrons with one spin and the other conducts with the other spin”, said Cespedes, which is why these materials could find their way into low-dissipation spintronic devices.

According to Papic, another class of materials, called ‘topological superconductors’, are strongly suspected to host a new kind of natural particle, called ‘Majorana fermion’.

A characteristic of topological states, said Papic, is that the millions of particles that make up the state are reluctant to leave it, adding robustness to systems which might otherwise be disrupted by temperature, noise, or other physical effect.

The Majorana fermion is a topological particle, which could be used to design qubits (quantum bits) for quantum computing in a similar way that electron spin is used create qubits.

But unlike many proposed qubits, whose quantum behavior is free to disappear (de-cohere), “these topological qubits would form a quantum computer which would be protected from de-coherence effects by topology,” said Papic. “So, topological superconductors are attractive as a potential platform for this new generation of quantum computers.”

And these theorized computers have been dubbed ‘topological quantum computers’, which is another phrase to keep your eyes open for in the coming years.


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