Context: In a paper published on June 21, researchers at Microsoft announced that they had figured out a way to create an elusive kind of particle that could potentially revolutionise quantum computing.
Supercomputing
Supercomputing technology comprises supercomputers, the fastest computers in the world. Supercomputers are made up of interconnects, I/O (input/output) systems, memory and processor cores.
- Unlike traditional computers, supercomputers use more than one central processing unit (CPU).
- These CPUs are grouped into compute nodes, comprising a processor or a group of processors—symmetric multiprocessing (SMP)—and a memory block.
- A supercomputer can contain tens of thousands of nodes. With interconnect communication capabilities, these nodes can collaborate on solving a specific problem.
- Nodes also use interconnects to communicate with I/O systems, like data storage and networking.
Supercomputing is measured in floating-point operations per second (FLOPS). Petaflops are a measure of a computer’s processing speed equal to a thousand trillion flops. And a 1-petaflop computer system can perform one quadrillion (1015) flops. From a different perspective, supercomputers can be one million times more processing power than the fastest laptop.
Quantum Computing
Quantum computing is a rapidly emerging technology that harnesses the laws of quantum mechanics to solve problems too complex for classical computers.
Qubit
A qubit (or quantum bit) is the quantum mechanical analogue of a classical bit. In classical computing the information is encoded in bits, where each bit can have the value zero or one. In quantum computing the information is encoded in qubits. A qubit can hold a one, a zero or crucially a superposition of these.
- A quantum computer can use individual electrons as qubits – its fundamental units of information. Information can be encoded in some property of each electron, like its spin.
Quantum Superposition
A quantum state in superposition can be seen as a linear combination of other distinct quantum states. This quantum state in superposition forms a new valid quantum state.
Quantum Entanglement
A pair or group of particles is entangled when the quantum state of each particle cannot be described independently of the quantum state of the other particle(s). The quantum state of the system as a whole can be described; it is in a definite state, although the parts of the system are not.
Concepts associated with Quantum computing
Spin
Qantum particles exhibit an intrinsic angular momentum component which is known as spin.
Anti-Particle
Dirac’s equation predicted the existence of an antiparticle for each particle, such that if the two meet, they annihilate each other. Based on his prediction, scientists found the first antiparticle, the positron (or the anti-electron), in 1932.
Bound state
The Bound state of a particle is that particular state in which two particles are energetically forbidden to be separated at large distances or potentially bound in that state.
Ground state
It is the state of a particle with lowest possible energy. Usually, particles do not show any degeneracy at ground state.
Degeneracy
Degeneracy in quantum mechanics means that a system can have multiple states at the same energy.
Topological System
Topology systems are concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself.
Topological Degeneracy
In topological systems, the system has multiple states at the lowest or ground state energy, i.e., the quantum system can exist in two (or more) possible states at its lowest energy.
Fermions
These particles have half integer quantum spin like 1/2, 3/2, 5/2, etc. This is why any particle, even something as large as an entire atom, can be a fermion, just its total quantum spin needs to have a half-integer value.
Non-Abelian Statistics
Under these rules, changing the order of steps in which you perform a task changes the task’s outcomes.
For example, say you have an algorithm that performs a series of steps in the order A-B-C-D. If the algorithm played according to the rules of non-Abelian statistics, A-C-B-D would give a different result from A-D-B-C.
Majorana Fermions and Majorana Zero Modes (MZM)
The quantum rules that apply to a single fermion also apply to pairs, or bound states. When the bound states are their own antiparticles – i.e., if they meet, they annihilate each other – they are Majorana fermions. Physicists call such bound states Majorana zero modes.
To be a Majorana zero mode, any bound state should satisfy two conditions
- It should obey the Dirac equation.
- It should be its own antiparticle.
Majorana Zero Modes helping in Computing
Quantum computers have a big problem, they’re very fragile and slight disturbances in the surrounding my result in the change of the quantum state of the particle and can result in change of the information.
- Majorana zero modes are a mathematical construction that allows electrons to be described theoretically as being composed of two halves.
- From a quantum computing perspective, if an electron can be split into two parts, then the information it encodes as a qubit will be protected from local perturbations.
Which makes Majorana Zero modes much more stable than most other qubits.
Also, MZM follows non-Abelian statistics which makes the outcome also dependent on the path taken in computation. So, the calculation done by MZM will have one more degree of freedom.
Current status of MZM
Indian Institute of Science associate professor Anindya Das said, “While topological quantum computing remains the ultimate goal, the existence of Majorana fermions hasn’t been settled yet. The result will need to be independently confirmed.”
