In 1937, Physicist Ettore Majorana hypothesized that within nature existed neutrally charged particles that acted as their own antiparticles. However, it was not until over 80 years after this idea was originally proposed that a joint effort between Researchers from both Stanford University and the University of California Los Angeles confirmed its existence.
Since its recent discovery, research on the potential of Majorana particles to be integrated into quantum systems has been a growing area of interest in this field.
A team of Scientists from the Center for Quantum Devices at Niels Bohr Institute (NBI) are leaders in this research initiative, as their recent publication in Physical Review Letters describes a laptop nanowire based on the properties of these extraordinary particles.
The Majorana particle, which can also be referred to as a Majorana fermion, acts as its own antiparticle, which results in its neutral electrical charge that prevents any possible unfavorable interactions to occur between the particles and any external components of a particular system.
Majorana particles differ from neutrons, which also possess a neutral charge, in that unlike these fermions, the interaction between a neutron and its opposing but equivalent anti-neutron would result in a complete annihilation of the involved matter.
Instead, Majorana particles overcome such adverse effects in their ability to interact within the same particle, thereby allowing for its useful potential in quantum system applications.
Quantum computing technologies are based on qubits, which operate according to the main principles of quantum physics that involve the superposition of particles that represent both 1 and 0 bits simultaneously, as well as qubit entanglement, which describes the state of one qubit, meaning whether it is a or 0, depending upon the state of another qubit1.
While the technologies that allow for the successful operation of classical computers involves the encoding of information only in bits of 1 or 0, quantum computers can function through a much more sophisticated mechanism that allows modern computers to improve their ability to solve difficult interaction problems.
In the NBI study, which involved a collaborative effort between Researchers from both Purdue University in the United States and the University of Copenhagen in Denmark, two ultra thin sheets were sandwiched together to form the Majorana laptop design.
With a layer of indium arsenide forming the bottom slice of the sandwich, and aluminum, a superconductor, present at the top of the sandwich, the complete structure sits on a wafer, which forms the basic building blocks of most modern computer systems2.
To create and incorporate nanowires into this structure, Researchers would previously manually assemble numerous nanowires in order to build a chip, which is an incredibly difficult and challenging task to complete.
However, the recent work by NBI alleviates this issue by specifically designing the nanowire into the sandwich structure that is present within the laptop, thereby making the reality of a quantum computer more of a reality now than it has ever been in the past.
Confirmatory results of the study presented by NBI are consistent with Majorana’s original theory that involves a decreased field-dependent gap of the nanowire, a peak conductance that is proportional to tunnel coupling and saturation present at at 2e2/h.
The one-dimensional nanowire in this study provides a stepping-stone in the challenging task of isolating Majorana particles and conducting experiments that will eventually develop complex quantum technologies and computer systems.
Further studies expanding on the principles developed in the NBI study will not only allow for a future fabrication of such Majorana-based computing systems, but also has the potential to improve the knowledge on the limited understanding that presently exists on the topic of Majorana particles.
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- “What is Quantum Computing?” – IBM
- “New ‘building material’ points toward quantum computers” – University of Copenhagen